All posts by Jonathan Hull

Eating Local: Butternut Squash

October 4, 2016GENERAL INTERESTJonathan Hull

by Jonathan Hull

“Eating local,” the goal of all of us who want to save the planet, presents special hurdles for residents of temperate climates such as NE Ohio: Our short growing seasons limit access to local fresh produce for way too long.

Yet there is at least one standard garden crop that can provide staple eating throughout the year—even up until (and even past!) the next harvest. I write of the humble butternut squash.

Raised and stored correctly, butternut squash can, with minimal special equipment or processing, provide year-round good eating. And let me emphasize the word “good.” At the end of this article, I’ll offer three recipes of which my family never seems to tire.

Squash to the Rescue

In my experience, squash is by far the easiest crop from the garden to store. Under proper conditions that I will outline below, it can easily keep for two years and potentially even more. I’ve eaten squash that was more than two years old that still tasted great. Once we settled on a specific variety—butternut—it became the highest yielding and most consistent crop from our garden from year to year. Grown in one raised bed 30 inches wide and only 32 feet long we have had harvests of between 150-175 pounds of squash! This averages out to about three pounds of squash every week for a year.

Site Selection:

The challenge to growing squash in a small garden plot is that these vigorous growers take up a lot of space. From the dimensions described above, our squash vines grew to take up more than five times the space of the bed they grew in.

Squash originally evolved in a partnership with mastodons and mammoths (a fascinating story for another time) and seem to have adopted the brash nature of their former partners. They go wherever they please in the garden and will happily overwhelm smaller plants. With proper placement, however, small plots can take advantage of squash’s exuberance without sacrificing a lot of space.

This placement involves planting squash at the edge of the garden. If your garden is contained within a trellis, fence, or a wall, then this might be a great place to grow squash vertically. If your garden is in a clearing of trees then squash can be allowed to grow in the border between the garden and the trees. The main consideration for growing squash in any placement is that it requires full sun.

In our case, we grow squash at the edge of the garden and the lawn and then train the vines to grow out over the grass. Since we already use a lawn mower for other parts of the yard, the space the vines will eventually grow into can be easily maintained. As the vines grow out onto the lawn, I set the mower to cut the grass very short for a pass or two in front of the vines. The vines can then effectively shade out the grass below them, and more or less keep the grass from growing high.

This way I can grow the squash in a small bed and only sacrifice a bit of lawn – of which we have plenty.

Soil Preparation:

If you are growing squash for storage, then you will be planting it in the summer. Be sure to keep its growing bed covered throughout the spring. This might be with a short rotation spring vegetable, a deep layer of mulch or a cover crop. Squash are heavy feeders and will happily grow in soil amended with heavy applications of compost. If I’ve got enough compost on hand I try to give the squash bed a double helping of compost spread to 4” deep. As in the rest of the garden, I amend the soil with various minerals as indicated through yearly soil tests. I also amend the garden every spring with recommended applications of broad spectrum mineral rock dusts such as Greensand and Carbonatite. Some growing guides recommend planting squash in ‘hills’, but since I use raised beds I don’t bother since the entire bed is a ‘hill’.

Selecting the best squash variety:

There is a dazzling diversity of squash varieties that grow fruits of various sizes, shapes and colors. Some will store longer than others. Some are more resistant to pests and diseases and some will have higher yields. Some may have better flavor or be better suited to certain dishes. As with other crops in the garden, feel free to experiment with different varieties. However, I have also found that there comes a time when you have to settle on a variety that works well for your circumstances year in and year out .

So for instance, I love the taste of the deep orange flesh of Hubbard squash varieties. However, I tried to grow this type for several years and never got a harvest. Insects called squash vine borers destroyed the vines. This led me to the butternut varieties which grow on thinner woodier stems that the vine borers avoid. Specifically, ‘Waltham’ butternut is the gold standard for storage squash in our garden. It is resistant to diseases such as powdery mildew and gives consistently large yields. It has a great flavor and is amendable to various dishes. It has a small seed cavity and comes in sizes that are suitable for cooking small dishes. When properly harvested, cured, and stored, the harvest from the year before will easily carry us through to when the next crop is ready to eat.

Planting:

Deciding on the best planting date is a balance between two considerations. First, squash love hot weather and grow best in soil temperatures at 90 degrees F. It’s best to wait until things really warm up in the summer to plant the seeds out. However, you don’t want to wait too long because you want to give the squash time to fully mature their fruit before the first frost sets in. Fully mature fruit is important for long-term storage. With that said, I’ve found it better to err on the side of a later planting date. Cool soil slows down their growth and even seems to stunt them for a time, so that any extra growing time is lost by getting them in too early. We are in Zone 6 and shoot for a planting date around June 15^th.

Warming Aids:

Since the weather doesn’t always give us what we hope for, we like to give extra insurance that our plants have the warm soil they like. In the past we used black plastic mulch to help warm the soil. It works well, but comes with downsides. It is hard to use with our soil building techniques such as in-season crop rotations, deep mulching and cover cropping. It always seems to be down when it’s needed up and up when it’s needed down. If you don’t have drip line irrigation, watering seems inconsistent as the water only has a small hole through which to reach the soil.

So this year I switched to using row covers and will never look back. These are spun polyester “sheets” sold under the brands Agri-Bond and Remay. We hang this ‘cloth’ over the bed with wire hoops.

They hold in just enough extra heat that all plants seem to love, but as opposed to plastic sheeting, they rarely need to be vented. They also let rain through, but keep existing soil moisture in.

About a week before I plan to plant our squash seeds, I will pull back any mulch from the soil surface to let the sun warm and dry it out a bit. I will also go ahead and put the row cover over the bed to get it warming even faster. After the seeds go into the ground, I will leave the row cover over the bed for a few weeks until the vines begin flowering. This is very important! Squash are pollinated by insects so you have to remove the row covers if you want any fruit. By that time they have leaped out of the gate and will be growing out of the bed space.

Growing:

It is easy to forget about squash as it is growing because it requires so little attention. So don’t forget to provide consistent water throughout the growing year. I keep an eye on the forecast and try to water before any real scorching hot summer days. This seems to help with heat stress for those days over 92 degrees. You will also need to train the vines in the direction you want them go grow. Do this early as it is easy to damage larger vines when trying to move them. Since squash are such heavy feeders I try to give them a foliar feeding every week if I can – with special attention to when they are in flower or are setting fruit. I typically use a combination of fish hydrolysate and liquid seaweed sprayed onto the leaves at the recommended application rate.

Harvest:

For the best storage you want to wait to harvest squash until they pass the “fingernail test”. When it’s difficult to press your fingernail into the rind of the squash, it’s ready for storage. You should have difficulty even making a mark. However, in practice I just let all the squash stay in the field until the weather calls for the first frost. A light frost will not ruin your crop but it will shorten its shelf life. So to keep things simple I go ahead and harvest the whole crop the day before the weather calls for a frost.

Cut the squash from the vine, but leave a few inches of the stem attached to the fruit. Do not pick up squash by the stem or it may break off. Squash without a stem will not store for long. Be gentle when handling them, as well. Bruises or gashes in the rind will also shorten their shelf life. Brush off any dirt, but do not wash the fruit to a squeaky clean. The microbes that are naturally on the fruit help to protect it from spoilage.

I put the fruit on racks in a single layer until I am ready to cure them.

Curing:

Before putting the squash away for storage, it is best to cure them in the sun for 7-10 days. This hardens their rind and extends their shelf life. Cover the squash at night or put them in a protected area if it is going to frost.

Storage:

Before I store the squash I organize them. Unblemished fruit with hard rinds I put in one pile that will serve as the long keepers. Any squash with blemishes or young fruit that might not have had time to fully mature on the vine I put in another pile (use the fingernail test). These we will eat first.

I put the squash in a single layer on bread racks and try to keep them from touching each other. Allowing air to flow all around the squash is key to long-term storage. Ideal conditions are temperatures at 50° F and 60% humidity. In practice any unheated space that doesn’t freeze in the winter and is moderately dry will do. We stack our racks on a shelf in an unheated basement.

Once you get the practice down it doesn’t take much to have squash on hand all year. Periodically check your entire store and pick out and eat any squash that are starting to mold. If storage conditions are not ideal and your stock begins to turn by the following summer you can always cut out the bad parts and cook the rest up a big batch. Freeze it and you can cook with it again later.

Cooking:

The taste of many squash varieties, including butternut, actually improves with storage. We keep a handful of squash from the previous year to cook with in November when all things pumpkin are called for. Butternut squash makes amazing pumpkin pie!

Here are a few recipes we love. Some are easy to make and are great “go-to” side dishes. It might seem dreary to eat a lot of the same food throughout the year, but we’ve found that food grown in your own garden in nutrient rich soil tastes so good it’s a pleasure to eat it at any time. Feel free to explore on your own: there are endless uses for butternut squash. You can use it in place of pumpkin or any other winter squash for that matter.

Curried Squash Soup:

Nothing warms you more on a cold fall night than a bowl of this soup!

Prep time: 5 minutes

Cook time: 25 minutes

Serves 4

2 tablespoons butter

1 medium onion, chopped

1 large carrot peeled and chopped

2 cloves garlic, minced

2 teaspoons fresh ginger, minced

1.5 teaspoons curry powder

1 can (14 oz) chicken or vegetable broth

2 pounds butternut squash

1 can (14 oz) coconut milk

1 teaspoon salt

roasted sunflower seeds (garnish)

Butternut squash seem to average about two pounds per fruit, which is perfect for this recipe. Cut the squash in half lengthwise and remove the seeds. Preheat oven to 325 degrees. Place the squash face down on a baking pan, then put them in the oven. Add a thin layer of water to the bottom of baking pan to steam cook the squash. Cook for an hour or until the flesh is very soft. Let the squash cool and then scoop the flesh out of the skin with a spoon.

In a large saucepan, melt butter over medium heat. Add onion, carrot, garlic, ginger and curry powder. Cook until carrots are almost soft, 5-8 minutes, stirring occasionally.

Add broth and bring to boil over high heat. Reduce heat to medium-low; cover and simmer until carrots are very soft, 10 minutes.

Transfer to blender or food processor and puree until very smooth. Return to pan and stir in squash, coconut milk and salt. Cook over medium-low heat until heated through, 2-3 minutes.

Garnish with pumpkin seeds, roasted sunflower seeds or cashew nuts if desired.

Butternut, Potato and Apple Mash

This is our go-to side dish for many a meal. The combination of flavors makes for something you can eat all the time. A side bonus is that we also grow a lot of potatoes for storage. It goes great with cider glazed chicken sausages.

Prep time: 10 minutes

Cook time: 40 minutes

Serves 4

1 small butternut squash (1 pound) peeled and cut into 1-inch pieces

1 large potato (10 oz) peeled and cut into 1-inch pieces

1 Granny Smith apple, peeled and cut into 1-inch pieces

1/3 cup of 2% Greek Yogurt

In a medium saucepan combine squash, potato, and apple. Cover by 2 inches water and bring to a rapid simmer over medium-high heat. Cook until squash and potato are tender when pierced with a knife, 15 minutes.

Drain vegetables and apple and transfer to a food processor. Process until smooth. Add yogurt, season with salt and pepper, and pulse to combine.

Squash Custard

This is also serves as a filling for an awesome pumpkin pie. But is also great on its own. We don’t like a real spicy custard or pie, so we backed off on the spices called for in this recipe just a bit, especially the allspice.

½ teaspoon nutmeg

½ teaspoon allspice

½ teaspoon cinnamon

1 tablespoon flour or cornstarch

1 ½ cups mashed cooked squash

½ cup honey

3 eggs, slightly beaten

1 ½ cups milk

Cut the squash in half lengthwise and remove the seeds. Preheat oven to 325 degrees. Place the squash face down on a baking pan in put them in the oven. Add a thin layer of water to the bottom of baking pan to steam cook the squash. Cook for an hour or until the flesh is very soft. Let the squash cool and then scoop the flesh out of the skin with a spoon.

Stir spices into flour and mix with squash. Then add honey, beating till smooth. Combine eggs and milk, and slowly stir into squash mixture. Ladle into custard cups. Set cups in pans of water and bake at 350 degrees F for about one hour.

Makes about three cups.

Jonathan Hull is a permaculture educator, designer, and consultant. After receiving his Permaculture Design Certificate (PDC) in 2006, he co-founded Green Triangle, a Cleveland area network of permaculture educators and designers. Jonathan is a Certified Permaculture Teacher and has been an instructor in several PDC courses and has taught a diverse range of workshops on topics such as soil restoration, bio-char stove construction, site mapping and home weatherization. He currently lives in Salem, OH where for the past ten years he has been implementing a permaculture design for an urban homestead.

Winds from Africa, Part Three

March 22, 2016GENERAL INTEREST, PASSION, PERMACULTUREJonathan Hull

by Jonathan Hull

The first two essays (Winds from Africa, Part One and Part Two) in this series explored the role of dust in nature from the biosphere to the microscopic world of plant leaves. We now turn to the garden. What are some practical applications of these discoveries?

Foliar sprays have been one application discussed throughout this series. I’ve used them for years, but this past season was the first I’ve done so consistently. The results I observed in the garden, in combination with deeper research into the topic, have convinced me to expand foliar spray use.

[Photo: Author’s Kitchen Garden]

These sprays have numerous formulations tailored for specific purposes. Some you can make with what is readily available, while others require the purchase of specialized materials. In researching this topic, I realized describing these formulations in detail would require a small book. In this essay, I will offer a few guidelines for general use, and later a peek into the most exciting aspect – targeted foliar applications.

I prefer making things myself because it is often the ecologically responsible option. There are numerous DIY foliar sprays one can make, and later I will detail one of these. However, until I’ve mastered the ability to consistently make and use my own formulations, I’ve decided to not let the perfect stand in the way of the good.

For general use, I opted for a solution easily purchased from a garden center. This is liquid fish hydrolysate mixed with seaweed concentrate. (Note that fish hydrolysate is different than fish emulsion.) The hydrolysate/seaweed spray provides plants with a broad spectrum of nutrients, but above all, phosphorus. Why is phosphorus so important? Phosphorus is nothing less than the currency of life! Every movement of every living being from plants to humans requires the expression of phosphorus.

Several brands include appropriate doses of phosphorus and other nutrients, but the one I used was Neptune’s Harvest. I followed instructions on the label, and began by diluting the concentrate with water. For reasons we will consider later, dawn is the best time to apply – dusk is second best. For a simple schedule, I adopted a weekly routine of spraying every plant in the garden, especially during spring, early growth, flowering and fruiting.

A sprayer is the main tool you will need–one that mists, not the flat spray jet some sprayers employ. Solo brand sprayers (http://solousa.com/store/flypage/handheld_sprayers/420_.html) have worked well for me. I have a small half-gallon version I use for seedlings and other small jobs. I have another three-gallon sprayer I lug around the garden, but this year I will be looking into a more ergonomic backpack sprayer. In any case, you will want a spray that mists up as well as down since you will want to coat the entire surface of the leaves, especially the underside. Many plants have the majority of their stomata on the underside of the leaf.

This is a bare bones general use application that is sure to give you good results. For more applications, the best guide I have found on the subject is the chapter “Foliar Nutrition” in Jerry Brunetti’s book The Farm as Ecosystem.

Putting Foliar Sprays into Context

The most exciting aspect of foliar applications is not their content, but their context.

[Photo: Author’s beneficial insect garden]

When I set out to write on this topic, my intention was to describe foliar applications analytically…take the subject completely apart in order to show how it works. Obviously, I decided to do otherwise. One reason, as I’ve mentioned, is that it is a big subject with a lot of complicated details. But more than this, my decision to take a different approach was to push myself to try a different way.

I’ve inherited a cultural tendency to view the world exclusively from a linear analytic perspective. I like tools and I like to study different techniques. This perspective is a great way to gain knowledge, but it is often a terrible framework from which to act. I can trace most of my mistakes and inefficiencies back to the fact that I had acted with a tool in mind instead of the context of its use.

Nature is rarely linear and its systems are complex, dynamic and adaptive. One of the many reasons I garden is to explore, enact and embody a holistic perspective. For similar reasons I’ve approached this series as an experiment in how to describe a technique holistically.

If we view the garden holistically as a complex adaptive system, what role can foliar sprays play?

Foliar applications find their most effective use if we understand that plants are the structural expression of the relationship between countless processes. If we are to engage responsibly in these natural processes then we must have some familiarity with them. Yet it is impossible to understand such a complex world directly. What is to be done?

We can represent the relationship between garden processes in a kind of shorthand – patterns. Patterns work much the same way as metaphor. The pattern I’ve used in this series is the relationship between the elemental processes of nature: sun, wind, water earth and the role of life knitting it all together. The vitality of any one plant could be understood as a particular expression of this pattern.

A plant in our garden is embedded in this pattern of elemental processes as it extends through the biosphere and deep into its history; but also in a different, yet similar, expression of this pattern in the microscopic realm on the plant’s leaf.

[Photo: Plant leaf showing fractal self-similarity. From: thereisnocalvary.wordpress.com]

The journey we took in Parts One and Two went through these different scales to show that patterns are fractal. Fractals are shapes that show self-similarity when you view them at different scales. One branch of a river has a similar shape as the whole river. This perspective allows the pattern at one scale to inform our investigation of another.

Here is just one example of how a pattern, in all its metaphoric power, came together in my garden.

My garden, Africa, and the Amazon

I had just finished spraying the plants in our garden. The sun was beginning to rise and its light was playing off the water droplets that were clinging to the plants. The birds were in full morning chorus. I was feeling the quiet, anticipative energy that comes at dawn.

The solution I sprayed was one that I picked up from a school of fertility management called Korean Natural Farming. It is a phosphorus solution made from animal bones. Here is how I made it.

Some time ago I started saving leftover bones from chicken and beef that we get from a local farmer. When I had enough of them, I cleaned the bones by boiling them in water. (As a bonus I got soup broth). I then let the bones dry, then charred them in a small stove of my own making, one that is usually used to make charcoal for biochar. I then soaked the bones for three weeks in apple cider vinegar to dissolve them into a solution. I diluted this solution further until it had a pH of 5.5, the same pH as plant sap. I then put this diluted solution into a garden sprayer that dispenses a fine mist and covered the entire surface of all the leaves in the garden.

[Photos: Author’s biochar stove (above)

Bone char before acid soak (below)]

If you recall from the first essay in this series, the fertility of the Amazon rainforest depends in part on the phosphorus contained in dust that originates in the Sahara. A significant portion of this phosphorus is from the bones of ancient fish. When it travels across the ocean, this phosphorus is transformed by an acidic weathering process that occurs in the upper atmosphere. As described in part two, when this dust settles on a leaf it starts a process by which a solution is spread over the leaf. This triggers the opening of stomata whereby the phosphorus moves into the interior of the leaf where it can be used in the plant’s metabolism.

This entire array: ancient phosphorus weathered from soil, complexed by ancient fish, eroded into dust particles by desert winds, acidified in the atmosphere, put into solution on plant leaves – was the expression of the same pattern that I had just used in the garden!

It dawned on me that the solution I was spraying, and the processes by which it was made, was unintentionally mimicking a natural process of global nutrient cycling.

Both begin with animal bones, which contains a special form of phosphorus. Since the phosphorus was structured by one set of living processes it is easily used by others. Charring bones weakens their crystalline structure, making the bones easier to dissolve—thus mimicking the decomposition of bones by desert sand. Soaking the charred bones in vinegar mimics the process of acid leaching as it occurs in the atmosphere. By spraying the solution into a fine mist you mimic the way in which African dust settles on Amazonian leaves.

The timing of the application was also orchestrated to harmonize with the pattern of natural forces occurring at the microscopic scale. The best time of day to spray is in the predawn hour. Why might this be? Our discussion in Part Two gives us some clues.

[Photo: Sunlight in morning dew. From: ntxhaiku.wordpress.com]

Plant leaves utilize a self-regulating system, the opening and closing of the stomata, to balance the need to breathe with the loss of water. Higher temperatures cause more water to evaporate, so that above 85 degrees a plants will close all of its stomata. By contrast, cool early mornings allow stomata to open their widest and breathe their fullest. (It has even been suggested that the specific frequency of morning bird song encourages the opening of plant stomata!)

Of equal importance to the foliar sprayer, predawn is also when humidity and dew are most concentrated, thus providing a ready-made liquid avenue into the leaves for your phosphorus solution..

I also time phosphorous application to the developmental stage of the plants. Phosphorus is in highest demand when plants are in early stages of growth. A lack of critical nutrients early on can dramatically reduce later growth. The so-called epigenetic system of a plant senses the lack of nutrients and curtails the plant’s developmental path. Perhaps the system designates a smaller frame of growth or limits how much fruit the plant will set. The plant may still benefit from supplemental phosphorus later in life, but in a certain sense the die will have been cast. In my experience, a small targeted application of phosphorus early in the year dramatically tips the balance of later growth.

Foliar spraying tips the balance of underground growth, as well. In this case, it is the growth of plants’ natural allies in the soil, the mycorrhizal fungi. These fungi, using powerful enzymes, break down the inorganic compounds where recalcitrant phosphorus typically resides and make it available to the plant. In return, plants feed the fungi energy in the forms of various plant metabolites they produce by photosynthesis.

[Photo: Mycorrhizal fungal threads attached to plant roots. From: gardenofeden.blogspot.com]

It’s a virtuous cycle. The more energy a plant can capture from the sun and bind to phosphorus the more it can feed the fungi, which in turn scavenge more phosphorus from the soil to transmit to the plant. But the cycle can also reverse. If the plant lacks sufficient phosphorus by which it transfers metabolites, it can’t feed the fungi, which then can’t access soil phosphorus. The whole web suffers.

Conventional soil agronomy “fixes” this problem by applying preprocessed, soluble phosphorus. Many plants then grab the freely available phosphorus and yield to the temptation to abandon their mycorrhizal partners. In so doing, plants inadvertently abandon other fungal benefits, including disease resistance. They also make themselves dependent on still more preprocessed inputs.

Here is the context for the incredible potential of foliar applications.

The phosphorus solution I sprayed, much like what is found in the dust from the Sahara, was in a highly bioavailable form. Unlike phosphorus in the soil, the plant did not need to expend energy to get it. By spraying it on the leaf, we bypass the potentially sluggish channel that moves from the soil, to fungi and then to the plant. Unlike conventional applications of phosphorus to the soil, foliar spray does not short circuit the natural plant/fungal symbiosis. In fact, spraying small amounts of foliar applied nutrients can actually jump-start interactions in the soil food web! The plant will use its free gift of energy to give its allies in the soil a leg up. The virtuous cycle is reinforced.

Imagine foliar sprays as the equivalent of acupressure in body work: small, targeted acts that have whole body effects. Plant health is largely determined by interactions in the soil, but foliar nutrition can be the tipping element that drives the whole system into new states of health. We’ve seen something similar in the first essay. The changing orientation of the earth with the sun was thought to be the main driver of climate change in the Sahara. But it was also determined that atmospheric dust was a “tipping element” that shifted the climate back and forth between different states.

Understood in this way, foliar application can be the tipping element in the creation of healthy soil itself! Plants are known to channel anywhere from 50-80% of the energy they obtain from photosynthesis into the soil. They do this to support a diverse suite of microbes (both fungi and bacteria) that facilitate plant nutrition and health. The healthier the plant, the more energy it can channel into the soil, the more microbes, the healthier the plant: another positive feedback loop. This represents an incredible input of energy into soil that can affect its physical, chemical and biologic characteristics. Foliar sprays that precisely target plant nutrient deficiencies can tip the balance of plant health and let the plant drive its own soil rehabilitation!

IV. Integrated Gardening Techniques Produce A Vibrant Food Web

This bring us to an important point. Foliar applications are no silver bullet! It is most effective when use in conjunction with other techniques that build healthy soils.

The most successful of the soil building techniques I’ve employed to this end are the following: water harvesting earthworks, deep mulching, cover cropping, composting with specific microbial communities, soil mineralization, subsoil de-compaction, no-till methods – to name a few. Foliar spraying is one of the newest techniques I have integrated into my practice.

[Photo: Author’s “Storage Garden” with water harvest earthwork (aka swale) at lower right]

For instance, I keep one garden bed a year growing a cover crop through the whole year. I spray this cover crop throughout the year, both with a broad spectrum foliar spray, but also with ones containing minerals found to be deficient in soil tests. Vegetative growth can be quite phenomenal. But more importantly, the soil condition after this cycle is equally incredible. I’ve applied compost to the garden for years and I’ve never seen the dark “crumbly” tilth that I’ve encountered by incorporating foliar sprays..

I’ve got a long way to go, but I’ve already witnessed remarkable improvements in my garden. Insect damage has shrunk dramatically. We used to dust our beans with Rotenone because the beetles would reduce the leaves to skeletons. The same with our cabbages and the damage done by caterpillars. By no means have these creatures disappeared from the garden, but they do so little damage now that we only occasionally pick them off our plants. The organic pesticides we’ve used in the past are now sitting unused on the shelf.

Species diversity in the garden has burgeoned. I use foliar sprays not just on our vegetables but also in those parts of the garden I reserve for plants that attract beneficial insects. Now instead of Japanese beetles and cabbage moths, our garden is overrun with their predators: assassin bugs and parasitoid wasps. More beneficial insects are attracted to the plants because the nutrient quality of the flower nectar and pollen has increased.

[Photo: Beneficial insects in author’s garden. Above and below– Assassin Bug and Syrphid Fly

Yields have also gone up. One of our most successful plantings was butternut squash in a 30 inch raised bed 30 feet long. From this area we harvested over 175 pounds of squash – easily doubling, if not tripling, yields.

Nutritional quality of our vegetables, herbs and medicinals has also increased. Brix levels (the standard nutritional measurement) has increased, as well as taste. It feels great to eat this food.

[Photo: Partial harvest from Author’s “Storage Garden”

V. Connecting With The Earth

“The ultimate goal of farming is not the growing of crops, but the cultivation and perfection of human beings.” Masanobu Fukuoka, in One Straw Revolution.

Maintaining a diverse, productive garden can be a complex and demanding task. It is easy to adopt a head down posture while in the garden, a kind of habit that relates to it only through a veil of tasks to be completed. Circumstances prevailed in piercing this veil.

A spark of inspiration sent me on this journey. A meditative moment in the garden revealed a pattern connecting an astonishing relationship: between dust storms in Africa, the fertility of the Amazon rainforest and my use of foliar sprays in the garden.

Foliar spraying was a garden chore transformed into work done in harmony with the elemental forces nature; an interplay between the sun and earth, water and air, plant and soil.

I felt the deep metaphoric power of the process I helped initiate. Using fire to transform bones into life-giving dust, working with the rhythm of the sun to use water in the air to channel these nutrients through leaf stomata to living communities unseen in the soil. As I moved across this landscape from the biosphere, to the garden and down to the microscopic; I found myself in this pattern – playing a tiny part in life’s work of knitting it all together. It was a brief moment of connection – of being deeply aware of being alive. This, I thought, is why I garden.

Winds from Africa, Part 2

March 15, 2016GENERAL INTEREST, PERMACULTURE, PERTINENTJonathan Hull

by Jonathan Hull

The following essay is part two of a three part series that explores how something as commonplace as dust can profoundly effect natural systems. Part one, which can be found here, explored its effect on the biosphere as a whole. This second part takes a microscopic look at dust on plant leaves. The third and final essay will be published next week. This essay will take what has been discovered in parts one and two and consider practical applications, by way of foliar sprays, in managing fertility in Ohio gardens. Foliar sprays have the potential of becoming one of our most powerful tools available in creating healthy gardens.

I. Reorienting

Our biosphere is an incredibly complex, dynamic and ever adapting play of forces. In the first part of this series, we met the main actors of this play in grand elemental forms: sun, earth, water and wind. The title role is played by life; the adaptive tissue that knits these elemental forces into a global system.

We learned that minerals in dust are essential to the function of the Amazon rainforest as well as numerous other ecosystems. Changing distributions of this dust and its effects on life can even modulate changes in global climate patterns ultimately driven by the earth’s orientation to the sun.

In the next part of our investigation, these same elemental actors will reprise their roles in another complex and dynamic play of forces. Only it will play out not on a global scale but on a microscopic one: the surface of a leaf.

[Figure 1: Microscopic detail of Leaf. From: Stomata Of Lavendula Dentata, Sem Photograph

Recall that this whole investigation started when I realized that the role of dust in global nutrient cycling had implications for the use of foliar applications in the garden. These are a broad range of techniques that attempt to boost plant health by changing the microscopic environment of its leaves. One technique that seemed to work well in my garden was one that covers plant leaves with a spray of minerals in a solution. I was a tentative proponent because I did not understand how this could work so well.

When I learned how much dust moves around the globe and how important it is to any number of ecosystems; the results from foliar sprays no longer seemed incidental. At the time it was pure speculation, but the thought occurred that it was entirely likely that plants adapted the ability to absorb minerals that were deposited on its leaves from atmospheric dust. This led me to research if this was indeed true and in doing so I learned the features of several important processes that take place on the leaf. These features will be incredibly important to my future use of foliar applications and to the realization of their maximum benefit.

II: When the Dust Settles

When you consider where plants first emerged in the history of life, it is not surprising that in some degree, they can all absorb nutrients through their leaves. Plants first evolved in bodies of water and most aquatic plants use their leaves as the main sites for mineral uptake.

Once inside the leaf these minerals can move throughout the plant via the liquid sap that connects the various metabolic functions that happen inside of it. This flow of minerals is critical to the function of a plant. For instance the electrical resonance of magnesium is essential to the structure and function of chlorophyll. Now in the case of aquatic plants, their leaves are structured in a way that allows them to be relatively open to the flow of nutrients. Their leaves can be open to this flow because the surrounding water buffers them from the effects of the sun and wind.

[Figure 2: Aquatic Plant. From: … quality for aquatic plants and fish | Activities and Information]

However, when plants moved onto land they no longer had this luxury. Separate and specialized structures were adapted for gathering the sunlight, nutrients and carbon dioxide needed for their metabolism. Roots, protected underground from the harsh effects of the sun and wind, became the main site for mineral uptake in land plants. Terrestrial plants still need to gather energy from the sun, so they adapted a waxy covering on their leaves called the cuticle. This was done mainly to protect the plant from the loss of too much water through its leaves by evaporation. An interesting side note for this discussion: this layer also protects the plant from excessive leaching of nutrients from its leaves by rain. In any case, this protective layer made leaves in terrestrial plants a lot less open to the flow of nutrients than those found in aquatic plants.

[Figure 3: Water on a Leaf. From: Beyond the Human Eye: Plant Cuticles]

This cuticle layer is the main barrier to the entry of nutrients. It is by no means impenetrable and there are practical strategies for moving nutrients through it, but this mechanism is outside the scope of this essay. Instead we will look at a more promising avenue. You see, the cuticle layer is not continuous because leaves cannot be completely closed to the outside world: plants also use leaves to breathe.

Plants breathe, oxygen out and carbon dioxide in, through openings called stomata. (See Figure 1 above). Thousands of these microscopic mouths can be found on the surface of leaves. Stomata also serve as thermo-regulators by allowing the plant to transpire water through these openings to cool the plant when needed. A self-regulating system exits within the leaf where stomata open and close depending on environmental conditions. The system balances the trade-off between breathing and losing too much water to evaporation.

When a stoma opens, it forms one tiny point of interface between the water inside the plant and the atmosphere. It might seem obvious that the stoma would be a convenient avenue for the entry of foliar minerals. But it is not that simple. In fact, for some time it was considered impossible for nutrients to enter the plant in this way. Although there are thousands of stomata on a leaf, added together they still comprise a tiny surface area. The dust particle would have to land in just the right place to make contact. Additionally, the vapor pressure from evaporating water flows out, which would seem to prevent the movement of anything in.

Recent research has found that a unique process that occurs on the surface of leaves in the presence of dust changes how the stomata operate. This process transforms stomata into a main avenue for the entry of nutrients. To explain this phenomenon, we need to understand what happens on the surface of a leaf where dust collects. How,we need to consider, does dust interact with a leaf.

The leaves of many plants have adapted structures to facilitate the collection of dust onto their surfaces. These include microscopic ridges in leaves that trap dust and tiny hairs that grow out of the leaves, called trichomes, which change aerodynamics on a microscopic level to pull even more dust to the leaf surface. With such microscopic adaptations, plant surfaces have evolved into the major sink for atmospheric dust. To give you an idea of the amount, one study in Chicago found that, urban trees, which occupy 11% of the city area, remove about 234 tons of dust from the air per year!

[Figure 4: Leaf Trichomes. From: Nettle Leaf Trichomes, Sem Photograph]

These particles are deposited on the leaf from dry dust in the atmosphere but also from particles left by evaporated rain droplets. Which come to think of it, you might wonder how much of this dust is washed off by rain. One study found that although the large particles of dust were washed from the leaves of trees the majority of smaller particles remained in the canopy. The study reported here, found that 75% of nitrogen that was deposited on a spruce forest never made it to the soil but was retained in the canopy!

Most of the particles of dust deposited on leaves are of a certain type that readily absorb moisture from the atmosphere. These are technically termed hygroscopic particles. On the leaf’s surface, they function in much the same way as they do in the creation of raindrops in the atmosphere; they serve as the nuclei for the condensation of water vapor. We might think of dust as dry, but in this case when considered at their own scale, they are positively soggy. Even at relatively low humidity levels, dust condenses water vapor on leaves where it would not otherwise stick.

Taken together, the moisture these particles gather produce the provocatively named “breath figures”: microscopically thin films of water that are invisible to the naked eye. These thin films of water remain persistent on the surface of plant leaves even under surprisingly hot conditions. Breath figures are not pure water, but a solution of the mineral particles that attract water from the air.

Breath figures have enormous implications for uptake of the nutrients into the leaf – especially through the stomata. In a newly opened “pristine” leaf, the liquid sap and all of the functions it connects are largely separate from anything that might occur on the leaf surface. Stomata on such leaves are just a tiny ports to the atmosphere. However, this new leaf quickly attracts dust particles, which, in turn, attract tiny films of water. Now when the stomata open, the liquid sap inside the plant connects to breath figures. The mineral can now land anywhere on the leaf and be connected to the stomata, and so connected to all of the functions that occur inside the leaf.

This continuous film of liquid that runs from the exterior of the leaf through the stomata and into the interior of the leaf is even thought to play a role in activating the opening of stomata themselves – a feedback loop that furthers the development on this continuous liquid connection.

Solutions always try to even themselves out. If there are differences in concentrations within the solution, called concentration gradients, the liquid will move from low to high concentration and high to low. The force of movement caused by concentration gradients can overcome the force of pressure moving water out of the stomata by evaporation. Thus, a flow of nutrients from plant exterior to interior becomes possible.

https://www.youtube.com/watch?v=dOXIsy3EoUQ&feature=youtu.be ]

Plants have adapted different responses to the formation of these continuous liquid connections. Certain plants are particularly reliant on inter-leaf nutrient cycling. In the dusty grasslands of South Africa researches have shown how trees can establish themselves in poor soils, even where grasses might otherwise have a competitive advantage.. As the trees grow taller, they collect more dust and thrive that much more. The cycle reinforces itself in a positive feedback loop.

However, it can also be the case that plant leaves provide too much of a good thing. If there are too many hygroscopic particles activating too many stomata, and so increasing evaporation through the plant, it can significantly lower its ability to deal with drought. In this case we have a negative feedback loop.

Plants that live near the coast have had to adapt to this problem. These plants can receive heavy deposits of sea minerals from salt spray that is carried off the ocean by winds. These plants have adapted leaf structures that rapidly shed particles so that they are not desiccated by the formation of continuous liquid connections and the resultant opening of stomata.

One issue that I will briefly mention: plants have adapted to environments that over evolutionary timescales receive relatively consistent amounts of dust. The problem is that in last 200 years there has been an 270% increase in particulate matter in the atmosphere – an increase caused by industrialization. Plants that had adapted to collect a steady stream of dust may now be overloaded. This increase in human produced particular matter, which has strong hydroscopic properties, has been theorized to be major factor in the decline of forests the world over.

We will consider all of these factors in the final essay in this series. Here we will discuss the practical use of all this knowledge in creating healthy and vibrant gardens. It should be noted, however, that we have highlighted only one tiny portion of a huge set of interconnected processes that effect how plants absorb nutrients through their leaves.

If one wants to master the use of foliar applications there is so much more that needs to be understood and even more that has yet to be discovered. Perhaps a topic for future essays, but as such it is out of our scope. However, what has been sketched out so far is a good foundation for incorporating this tool into a general gardening practice.

….. Winds from Africa ….. A Deep Breath, Part 1

March 1, 2016GENERAL INTEREST, PASSION, PERMACULTURE, PERTINENT, POETRYJonathan Hull

by Jonathan Hull

My mind was churning, neurons were firing in sync; a pattern had been recognized. What got the idea mill running was when I learned of the astonishing relationship between dust storms in Africa and the fertility of the Amazon rainforest.

Behind this process of global nutrient cycling was a set of relationships, a pattern, that had exciting implications for fertility on a much different scale: in the garden. Ideas began to tumble one after another that centered on just how important foliar applications could be in facilitating the growth of nutritious food and potent medicinals. And, for me, the biggest question of all: What would the African/Amazonian relationship mean for my own garden in Northeast Ohio?

I. Introduction

Foliar applications are a broad range of techniques that attempt to boost plant health by changing the microscopic environment on its leaves. I have had impressive results using a few of these techniques, but until recently I did not fully understand how they worked.

It might seem strange that a process occurring on a global scale could lead to a breakthrough in understanding one that happens on a much smaller scale; but I’ve found such cross scale connections to be very illuminating. It can be a way to shake the mind out of its tendency to view things in isolation. It is easy to get hung up on tools and techniques without considering the context in which they are being used. As the expression goes “to a hammer, the whole world looks like a nail.”

However, understanding the context of our actions is easier said than done. If you are like me, then you were trained to act in a world that is thought to operate in a linear, static and superficial way. But this is not how the natural world works. Natural systems are complex, dynamic and adaptive.

We might look into the garden in a superficial way and see plants that are “under-performing” and grasp at the latest fad to whip it into shape. Not only is this kind of thinking dangerous, the picture of the world it produces is dreadfully boring. Instead we could look at the structure of a plant as a flow of energy. This flow of energy is the expression of relationships between an innumerable set of processes.

With this picture of the world, we will see that some of these processes structure this flow of energy with the broadest strokes. The latitude where this plant looks out toward the sun will pattern it in the most profound way. The climatic patterns in which it grows, whether it is near an ocean or up in a mountain, will affect the flow of energy that is this plant. Right now the structure of any plant is the expression of relationships between processes that happened eons ago. It might be most vibrantly healthy when growing in soils containing minerals brought in by now-long-absent glaciers.

There are also those processes that fill in the details of the larger processes in which they are embedded. A plant might be growing in a certain way because it is in a small depression in the earth that protects it from winds and extends the heat energy of the sun. A plant might be growing well because the flow of energy through it is being facilitated by all the minerals it needs for its metabolism. These minerals might have been pulled from a rock by a bacteria so that the plant could absorb it. The shape of the quantum vibration of one these minerals might be structuring an enzyme that dramatically speeds up chemical reactions in the plant.

It can be both breathtaking and dizzying to look at world in this way. Any picture of such a complex world is going to be limited. It also might seem strange to spend all this time exploring when all you want to do is grow food. But I think it is an essential exploration if we are to participate responsibly in the world. If we want to dance to the rhythm of life than we have to listen to its music.

This is the kind of exploration we are going to make in regards to foliar applications. We will start on the global scale. There is a process of global nutrient cycling that dramatically patterns the structure of the natural world. This global process will help us understand how we can use foliar applications to cycle nutrients in our garden. Some of what we will learn will have direct implications for our practical efforts. Other things we might learn might not be practical but will be grist for the intuitive mill.

Lastly, I wanted to explore this connection for more than just its utilitarian value. I like to garden not just for food but because even the most practical work participates in a great chain of being that runs through worlds incredibly small to those incomprehensibly vast. Researching this topic deepened my awareness of how profoundly the natural world is shaped by its interconnectivity. This awareness of interconnectivity sparks in me a sense of awe – an awe in being part of the living tissue of organism earth.

This was all the more the case when I learned of the importance of dust.

II. Dynamics of the Global Ecosystem

The Amazon rainforest is at odds with what I’ve learned about soil. In most terrestrial ecosystems, nutrient rich soil is the foundation of a healthy biome. Rainforests are burgeoning with life, but more often than not they sit atop notoriously poor soil. How can this be? One explanation is that in rainforest ecologies, nutrient cycling happens at breakneck speeds. Nutrients in dead organic matter do not have time to build up in the soil because they are quickly reassembled back into living tissue. A number of plants called litter trappers have even evolved to capture organic matter before it makes is to the forest floor!

These soils are also lacking in nutrients because they are weathered soils. The torrents of rain that give these forests their name comes with a price: all that water leaches minerals out of the soil profile. The rainforest might be a prolific nutrient recycler, but with so much rain it is inevitable that soil minerals are carried away in rivers and eventually deposited in the ocean.

Chief among these important minerals is phosphorus. In the orchestra of life, phosphorus plays a central role in the flow of energy in all living things. However, when it is in an inorganic form it is anything but energetic. It is not easily induced into biochemical processes so that only a small portion of phosphorus in an ecosystem is being cycled through living systems. The rest is much more likely to be leached away by weathering. In soils that are heavily weathered, phosphorus is often the limiting factor in plant growth.

Unlike its northern cousins, forests in the Amazon have not had their soil minerals renewed by the erosive power of ice age glaciers. One would expect that without such an input, the slow and steady loss of soil minerals like phosphorus would degrade the biomass potential in a kind of ‘wet desert’ ecosystem. Yet, where civilization has not wreaked havoc, these biomes are unmatched in their vibrant diversity. What gives?

An explanation is found in the amazing story of how dust storms that occur in the Saharan desert in Africa fertilize the Amazon rainforest in South America.

[Fig. 1]

The dust borne on continent-spanning winds is rich in minerals like the all-important phosphorus. This critical input of dust has been found to perfectly balance what is leached away by rain and lost to the ocean! How wondrous that two biomes at such complete extremes and separated by an ocean of water can be so intimately connected!

Equally incredible is the set of finely tuned processes that allows for this instance of global nutrient cycling. The majority of Saharan dust that falls in the Amazon comes from one small area called the Bodélé depression. It is only .5% the size of the Amazon and only .2% of the Sahara, but it is the greatest contributor of global atmospheric dust, emitting on average over half a million tons of dust per day!

[Fig 2.]

A small area producing such an immense volume of dust is only possible because of a very specific set of geographic and meteorological circumstances. Geographically the Bodélé depression is located at the mouth of two large magma formations. These formations are situated in just the right way that they focus and accelerate, like breath through a straw, powerful winds that carry the dust aloft.

[Fig. 3]

These winds, referred to as low-level jets, are unusual in themselves and only formed because of a particular set of regional conditions including the shape over northern Libya of the high altitude globe spanning jet-stream. The directionality of this low-level jet is important because it moves the dust into the right position to be picked up by the higher altitude winds that travel to South America.

The Sahara and the Amazon are not just spatially linked, there are also processes that link them through time. The dust from the Bodélé depression isn’t any old dust. It is uniquely mineral rich because this area was once at the bottom of a vast freshwater lake.

Thousands of years ago the Sahara was a different environment – more closely resembling the Amazon than the desert we see today. It was full of rivers and lakes that teemed with life. The Bodélé depression was the lowest point in the largest of these lakes – Paleolake Megachad. At its peak nearly 7,000 years ago it was larger than all of the Great Lakes combined. Global climate patterns shaped the jet-stream so that it brought the monsoon rains further north than it does today. Lakes like Megachad were supplied with nutrients that were washed from the soils of Northern Africa by these monsoon rains. These nutrients in combination with the steady sun shining on this equatorial latitude made for the biological equivalent of a freshwater paradise.

The ancient creatures that populated Lake Megachad complexed and concentrated these essential minerals as part of their metabolism. Once integrated into a biological process many of these minerals cycle within the ecosystem (see below), but as we have seen some is inevitably lost to the system. In this case, when aquatic creatures die some of their remains collect on the lake bottom.

One of the more important creatures for our story is a group of microscopic algae called diatoms. As a function of their metabolism they secrete tiny crystalline shells made of silica. The Bodélé depression is absolutely chock full of these tiny shells – a deposit called diatomite – so that the dust that blows from this area is predominately composed of them. The hollow structure of these shells make them incredibly light and explains why the dust can travel such vast distances in the upper atmosphere.

[Figure 4]

Higher forms of aquatic life, like fish and turtles, complexed and concentrated minerals in their bones and scales. These also fell to the lake bottom and are also present in deposits found in the Bodélé depression. The diatomite mentioned earlier erodes these bones like sand from a sandblaster. The result is that a significant portion of the phosphorus that settles on the Amazon originated from the remains of ancient fish!

This is important because as we detailed earlier, phosphorus that is in an inorganic form is resistant to being incorporated into biologic processes. On the other hand, the phosphorus found in fish bones is dramatically more bio-available. In fact, all of the phosphorus that travels in the dust is altered by a process of acid leaching that occurs in the atmosphere. This acid leaching makes all forms of phosphorus more water soluble; an important step in making it more available to biological processes. These are critical factors in the fertility of the rainforest and will be processes that we will mimic in the practical discussion of foliar applications to follow.

At some point in the last 5,000 years, the climate of the Sahara shifted dramatically. The monsoons no longer tracked north to fill its lakes. The prime driver of this shift is a change in the orientation of the earth’s axis. It is remarkable to think that the global cycling of nutrients that is occurring between the Sahara and the Amazon is itself embedded in an even larger process occurring between the earth, sun and moon!

Yet this might not even be the most incredible part of this story. Although a change in earth’s axis may have been the prime mover of this shift in climate, how it shifted suggests a more complex process. It shifted in a disturbingly rapid fashion, which the gradual change in the earth’s axis does not fully explain. In something called the North African climate cycle, it also vacillated several times between two regimes of a wet Sahara and dry Sahara.

Recent studies have suggested that changes in global vegetation patterns may have both dampened and amplified the effects of earth’s shifting axis, triggering what regime the climate favored in this region. One provocative theory has even formulated that cycles of excavation and deposition of the Bodélé depression may itself be responsible for these climate cycles! In simplified form: as the depression is emptied of its mineral rich deposits, it prompted a degradation in vegetation patterns. This prompted a change in global climate patterns, which among other things favored a change in the track of the monsoon. This allowed for the depression to once again be filled and for the cycle to continue. This is global nutrient cycling occurring on a truly grand timescale.

Although highly speculative, this theory has more going for it than just changes in vegetation patterns. The dust from the Bodélé depression also has a huge effect on the size and type of phytoplankton blooms that happen in the Caribbean Ocean (in this case iron is the limiting nutrient of which this dust is also rich). Supporting a number of major ecosystems means that this dust is involved in sinking vast amounts of atmospheric carbon. In combination with a number of other effects like cloud physics and radiant heating, the dust from this area is being considered as a “tipping element,”a force that can determine the larger state of global climatic patterns.

Clearly atmospheric dust is incredibly important to the global ecosystem. Many other ecosystems are dependent on mineral inputs of atmospheric dust that originate from other parts of the world. Jared Diamond, in his book Collapse, cites the varying distribution of volcanic dust as a factor that determined why some Pacific Island cultures endured while others did not. Closer to home, the forest of Eastern North America also receive important inputs of minerals from dust.

But it was the role of dust in the Amazon that triggered the “AHA! moment” that started this exploration. I’ve studied a lot about healthy soil and continue to work on building the best soil I can for the creatures in the garden. When I learned about foliar applications I could never see how feeding the plant through its leaves could have near the effect as feeding it through the soil. But when I tried them they seemed to work quite well. How could this be?

The inspiration came with the thought: if plants in the Amazon are growing in nutrient poor soil, perhaps they adapted the ability to trap and absorb the minerals from dust that fell on their leaves before it even reached the soil? Might all plants have on their leaves something akin to microscopic litter trappers?

This will be the starting point for the next installment in this series, where I will present evidence that this may indeed be the case. From the global processes we have charted here, we will take a journey into the microscopic ecosystem of the leaf–including the leaves in our Ohio gardens. Stay tuned!

Photo Captions/Credit:

Figure 1: Conceptual image of dust from the Saharan Desert crossing the Atlantic Ocean to the Amazon rainforest in South America. Image via Conceptual Image Lab, NASA/Goddard Space Flight Center

Figure 2: NASA image courtesy the MODIS Rapid Response Team, oddard Space Flight Center

Figure 3: The surface wind focusing toward the Bodélé. Right: 3D topography of the Sahara; left: a rare shuttle image of emission from the Bodélé between the Tibesti and the Ennedi mountains. From: The Bodélé depression: a single spot in the Sahara that provides most of the mineral dust to the Amazon forest:

Figure 4: Coloured scanning electron micrograph (SEM) of a Triceratium sp. diatom. By Steve Gschmeissner. : http://fineartamerica.com/featured/26-diatom-sem-steve-gschmeissner.html

Figure 5: Sub-fossil skeleton of a 1.15 m long Nile Perch preserved within diatomite on the floor of palaeolake Mega Chad within the Bodélé. From Solid-phase phosphorus speciation in Saharan Bodélé Depression dusts and source sediments.

GARDENOPOLIS Cleveland

Greening a City — news from the trenches

All posts by Jonathan Hull

Eating Local: Butternut Squash

Winds from Africa, Part Three

Winds from Africa, Part 2

….. Winds from Africa ….. A Deep Breath, Part 1