Category Archives: PASSION

Happy Thanksgiving from Gardenopolis!

This Thanksgiving, we thought we’d share some of the garden plants we’re most thankful for. 

Ann McCulloh:

Seems like I’ll be planting bulbs until the ground freezes solid, and some of my very favorite bulbs are the Alliums. There are many varieties of this charismatic onion relative, which bloom at various times in spring, summer or fall. All the tiny florets provide wonderful nectar for bees and butterflies. Best of all, the deer don’t like ’em!

The appeal of Eastern Bayberry (Morella pensylvanica) for me is the wonderful fragrance of the leaves and berries. Since this salt tolerant, semi-evergreen shrub makes a beautiful hedge when pruned regularly, there’s plenty of opportunity to enjoy the scent when trimming it. Lots of birds eat the berries, too!

I welcome frost this time of year, once the houseplants are safe inside – it means a break from laboring in the garden! Another benefit is the softening, sweetening effect it has on the fruits of the native persimmon, Diospyros americana. The variety ‘Meader’ is hardy, self-pollinating and can be easily kept at 12′ tall. Beautiful orange fall color, too.

Catherine Feldman:

Pyncnantheum… native mint. Grows in part shade. Fresh pepperminty smell. Extremely attractive to pollinators midsummer through fall. Spreads by runners. Lovely blue grey foliage — color seems to deepen as the season passes.

Elsa Johnson:

A pleasing combination in fall is Amsonia hubrichtii, Sedum spectablis, and carex.

Amsonia hubrichtii… the amsonias are big clump forming perennials, though not at first, so patience is needed for the first couple years, especially in semi shade. All amsonias have pale, pale blue flowers in spring. Hubrichtii has fine thread-like leaves that turn a deep gold in the fall and is an aesthetic wonder, adding both color and billowing soft texture.

Sedum spectablis…a common garden perennial that is also a great pollinator attractor. The blossoms darken to shades of rosy russet in the fall and really stand out against a background of amsonia hubrichtii.

Carex… this is a cultivar I found ….it reminds me of hair. I find that if carex looks too much like ordinary grass my non-gardener clients think they are grass and weed them out. A non grass color like variegation seems to help.

Nyssa sylvatica… one of my favorite trees. Common name Black Gum . This is an easy to grow tree that is adaptable to many environmental conditions once established, and resistant to many diseases and pests. Has shiny dark green leaves that turn to crimson in the early fall. Deer like to browse the young leaves, so protection is needed while the tree is young.

Sassafras… Tends to grow in a thicket. In a good year the leaves turn marvelous mixed shades of yellow and gold flushed with coral.

Tom Gibson:

My favorite pollinator attractor?  Without question it’s boneset, eupatorium perfoliatum, which not only attracts the usual cast of honey bees and bumblebees, but all kinds of wasps, beetles and flies that often rely on pollen for just part of their diet.  I’ve already written about boneset, but the annual early August show continues to pull me in.  I will stand for 15 minutes at a time just to watch the ecstatic, oblivious activity of the dozens of insect visitors.  Here’s an ailanthus web worm with a mason bee:

Another favorite is the hardy ageratum (Conoclinium coelestinum).  It’s not mentioned nearly as much as milkweed as a food source for monarchs, but the butterflies always make a stop on these light blue flowers on their way south during the fall.

Finally, there’s Jacob’s ladder.  It’s one of the first plants to bloom in the spring and is a great source of early nourishment for queen bumblebees, whose self-heated “blood” enables them to begin establishing nests in cool weather.

Jacob’s ladder grows prolifically in my shade garden.  It happens to bloom at the same time as my red and black currant bushes, so Jacob’s ladders provide a nice assist in getting fruit started.

Winds from Africa, Part Three

by Jonathan Hull

The first two essays (Winds from AfricaPart 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. 

Figure 1

[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 ( 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.

Figure 2

[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.

The fractals of nature
The fractals of nature

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

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.

Figure 4

[Photos: Author’s biochar stove (above)

Bone char before acid soak (below)]

Figure 5

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.

Figure 6

[Photo: Sunlight in morning dew.  From:]

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.      

Figure 7[Photo: Mycorrhizal fungal threads attached to plant roots.  From:]

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. 

figure 8 

[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.

Figure 9  

figure 10

[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.

figure 11

[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 ….. A Deep Breath, Part 1

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.

Figure 1

[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!

Figure 2[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.

Figure 3

[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

[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!

Figure 5

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. :

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.

A Book Review by Elsa Johnson: Richard Mabey’s “A Cabaret of Plants”

by Elsa Johnson

British Naturalist Richard Mabey’s book, A Cabaret of Plants, is not a book to which one can do justice in a mere few hundred words, nor can one truly do justice to the reading of it while drifting in and out of a haze of pain meds (recent hip replacement), hence, this essay – which is not so much a meditation as a meandering.

Here in Cleveland, Ohio, in the heart of the Eastern Broadleaf Forest, we have tended to take the abundance and diversity of our hardwood vegetation for granted – until we are reminded by loss or impending loss that, though seeming more durable than people, trees are vulnerable, too. Thinking that they are enduring, we are dismayed when they are stricken by disease. But we soon forget them.  We do not even remember our native chestnut trees (chestnut blight); the American elm —  anyone? (Dutch elm disease). Our memory of these once iconic trees grows limited — and it is a fact that we must remember, in order to value what we have lost.  More recently: ash (ash borer); oak (oak wilt); white pine (blister rust); hemlock (wooly adelgid ).  Who knows what is coming next to a tree near you. So, perhaps, it is time to consider the larger picture of what trees mean to us – so much more than just an (important) ability to sequester carbon.

Mabey is excellent at this sort of thing, so I picked out a chapter — From Workhorse to Green Man: The Oak — and drifted in.

There are, Mabey tells us, 400 to 600 species of oak spread across the northern hemisphere – a plant family that is quirky, opportunistic, mutable – and useful.  From the Neolithic era on, the oak has been a crucial raw material, often used for surfacing some of mankind’s earliest walkways, like the Sweet Track, that crossed the Somerset marshes in England. That wood, well preserved, has been dated back to 3806 BCE, when it was cut.  In France, an oak tree in Allouville-Bellefosse, 1,000 years old, contains, within its hollow trunk, two chapels, built in 1669. They are still used for Mass twice a year. We  learn that the roof of Westminster Hall – containing 600 tons of wood spanning seventy-five feet without a central support – is essentially a ‘super-tree’  through an arrangement of trunk and branching that ’would not work unless it copied the structure of its motherlode’.  And we learn that Ely Cathedral, built at the end of the 12th century, and called the Ship of the Fens, has an interior that resembles a ‘carved simulacrum of a an oak forest’ … and that the carpenter there altered his design to use several trees that were not quite long enough to reach all the way up to the roof’s spectacular octagonal lantern (well worth googling to see). In England, as in nowhere else, it seems, the oak became emblematic of nationhood and character.

Mabey also tells us it is not by coincidence that that oaks and humans share habitat preference and are coterminous – oaks having been an important food source. Eventually, Mabey gets around to the Green Man — those foliate heads that are emblematic generative figures of mythic — possibly demonic — creativity, and which, oddly,  often reside in churches but fit no formulaic interpretation. Mabey calls them ‘an irresistible eye-worm for stone carvers.’ In the Lady Chapel at Ely Cathedral, many of the carven images of Mary were smashed or decapitated during the Reformation (the ISIS of its day) – but the Green Men and the symbolically sinful foliage were puzzlingly intact.

Perhaps,  Mabey suggests ‘ the exuberant carving  seems a celebration of the unbroken connectivity of the living world’.  So I leave you with that, and a poem , which also celebrates the organic vitality of the Green Man.


Home Permaculture Design Course

Thursdays at 7:30 to ~8:45 PM

March 10-April 28 at First Unitarian Church, Shaker Heights

Find a new way to combine aesthetics, edibility, and low maintenance in your yard by better understanding the Interdependent Web of Life.

hoverfly and dill

planting dill attracts adult hoverfly pollinators who lay eggs…

Hover Fly Larva Plain

…that produce larvae that prey on aphids.

Our goal with this course is to teach you fundamental permaculture principles and help you apply them to a project you can implement.   Previous students have redesigned parts of their front or back yards or helped launch major institutional projects. 

This will be our seventh iteration of the course (three previous at First Unitarian and one at the Cleveland Botanical Garden and all to positive reviews, including such comments as “life changing”).  Taught by Green Paradigm Partners: Elsa Johnson, landscape architect, whose gardens have been featured on multiple tours and in Fine Gardening magazine; and Tom Gibson, award winning permaculture garden community organizer.

Cost: $175 per family unit (i.e. your partner can come free), with 20% going to the First Unitarian Permaculture Garden.

Contact:  Tom Gibson ( 

What’s So Great About Hoverflies?

by Tom Gibson

Imagine sitting down with an impassioned collector of buttons to discuss his triumphs. First, a large red button discovered in an attic in Toronto.  Then a rare pearl button found at a second-hand store in Cleveland, followed by a detailed description, which the collector imagines to be droll, of the store’s eccentric proprietor. 

How soon before you want to scream?

That was my reaction to The Fly Trap, written by Fredrik Sjöberg, who has devoted his life to collecting hoverflies (202 separate species, according to the book) on an island off the coast of the Swedish mainland. I bring this book to the attention of Gardenopolis Cleveland readers because you might well be tempted to read it.  It made this year’s New York Times list of the 100 Notable Books and has gathered high praise from a Swedish Nobel prize winner and various reviewers:  ”A rare masterpiece…Graceful, poetic, astonishing, and–yes!–absolutely thrilling.”

Not. (One is reminded of a real Scandinavian masterpiece, The Emperor’s New Clothes.) The author displays an astonishing lack of enthusiasm, given his subject matter, for either nature or for the lives and roles of hoverflies; his main thrill comes from discovering species that others haven’t. In a burst of candor, he even admits to the narrowness of his passion when he describes it as “buttonology,” the collecting of something special  just to him. Only other collectors of things–saw flies, dragonflies, but also porcelain and painting seem to resonate.  Otherwise, he’d rather be alone on his island.

Instead of reading this book, I would encourage Gardenopolis Cleveland readers  to savor the real pleasure of observing hoverflies in your own gardens. They hover (of course) over your flowers, wings beating at 120 times per second, before diving in to gather pollen and darting to a neighboring blossom.

They are also a great example of mimicry in nature; though harmless in their adult stage, these two-winged flies (Diptera) have evolved to scare off predators by resembling more dangerous four-winged wasps (Hymenoptera).

Their greatest value to the gardener, however, may be the insatiable appetite their highly predatory larvae have for aphids.  One larva can eat 50 aphids a day!

Hover Fly Larva Plain

Fortunately, many familiar plants attract them, including fennel, lavender, cosmos, and dill (larger list here:  Here’s a hoverfly eating dill pollen:

hoverfly and dill

Perennials that won’t tolerate leaf mulches by Thomas Christopher of Garden Rant

GARDENOPOLIS Cleveland thanks Thomas Christopher and Garden Rant for this interesting and relevant article.

Perennials that won’t tolerate leaf mulches by Thomas Christopher

In a recent post, Evelyn Hadden shared some very useful tips on how fall’s leaves can be used in the garden.   As a perennial enthusiast, I’d like to add a couple of caveats – a mulch of autumn leaves can be fatal to certain kinds of perennials.

A mulch of freshly fallen leaves applied an inch or two thick, or even just a heavy leaf fall from nearby trees, tends to keep the ground beneath it damp, especially if the leaves are large and you don’t shred them before applying them (I always recommend shredding leaves with a dedicated leaf shredder or a lawn mower when using them as mulch).

Because they keep the ground damp, leaf mulches of any kind, shredded or otherwise, are not beneficial for silvery, woolly-leaved plants such as lamb’s ears (Stachys byzantina) or lavenders (Lavandula spp.).  These plants are adapted to dry sites — their silver hue and hairy surface are adaptions to protect them against dehydration and drought – and they will rot if  kept consistently damp.


Gray, hairy plants like this lamb’s ear won’t tolerate leaf mulches 

Other perennials that won’t tolerate prolonged dampness include many culinary herbs such as thyme, oregano, and sage, all of which are native to the dry, rocky soils found around the Mediterranean. In fact, Mediterranean plants as a whole generally do not flourish when swaddled with leaves.

Succulents likewise will rot if kept damp; keep leaf mulches away from your sedums.  Alpine plants are also vulnerable to damp, especially in wintertime – do not use leaf mulches in the rock garden (a gravel mulch is far better there).

Finally, as Dale Hendricks emphasized in a recent email, leaf mulches are also problematic for herbaceous evergreens such as heucheras and hellebores.  If the mulch is applied simply by raking or blowing leaves onto the garden bed, then it is likely to bury the perennials’ foliage and interfere with their wintertime photosynthesis (a heavy leaf fall from nearby trees can achieve the same thing if left undisturbed).  When used around evergreens, I recommend shredding the leaves thoroughly and then tucking the mulch in by hand so as not to bury the foliage.


Care must be used in mulching evergreens like these coral bells

Photos by Susan Harris.

Perennials that won’t tolerate leaf mulches originally appeared on Garden Rant on November 28, 2015.

Nature at Night

by Tom Gibson

Like my colleague, I respond to the beauty of Manet’s and Monet’s gardens, but perhaps a little less enthusiastically. I like my Nature more “tooth and claw.”  I was fascinated this summer, for example, when I saw a wasp stumbling across the ground of my garden carrying paralyzed prey on its back and looking for its burial hole (and egg-laying site). Something like this…

Digger Wasp

So it should come as no surprise that my favorite artistic renditions of nature lean more to Bartok.  He was enthralled by the sounds of “Nature at Night” and kept returning to that theme again and again.

Here’s a typical movement from a Bartok piano piece entitled “Out of Doors.”  Go to minute 6:38:


Here’s an even more ominous version of Nature at Night , the Bartok #5 string quartet played by the Takacs Quartet.  Go to minute 9:13:

It Ain’t Over (Don’t start Persephone’s Lament, just yet)

by Ann McCulloh

This ecstatically blue and gold November day, with temperatures in the 70s and honeybees buzzing happily in the purple aster blossoms, gives ample support to my passionate assertion: “The season’s not over, everybody!”

allyssum and parsley

I resist with every fibre of my being the common idea that gardening in Cleveland begins on Memorial Day and whimpers to a close around Labor Day. End the calendar’s tyranny! Don’t go inside before the snow flies! Everywhere you look there’s evidence of abiding life. It’s in the late blooming asters, monkshood and mistflower. Witness the fresh blossoms of borage, calendula, allysum and roses that spring forth with new vigor now the nights are cooler and the rains more abundant.

allyssum and parsley

My zucchini and summer squash are putting out new fruits.

zucchini in november

Fresh rosettes of tasty foliage emerge at the base of all my herbs: parsley, mint, oregano and lemon balm – just in time for me to cut and dry for the onset of winter. One of my favorite salad greens, mache (aka corn salad, and Rapunzel salad) scattered its seeds in May, to lie dormant all summer. Look at it popping up through the straw everywhere!

corn salad

This is a tender little rosette like miniature Boston lettuce, which can be harvested from now through March from under a covering of straw and snow. Kale, collards, chard and tatsoi are other cold-hardy greens that won’t quit for just a few frosts.


All this and more tell me there’s always plenty going on both above and below ground (where the growing never really stops.) I may retreat indoors for a month or two. But come January there’s “winter sowing” of hardy perennials and cold-loving annuals (more on that in a future post), branches to cut and force indoors, and the flowers of witchhazel, Lenten rose and snowdrops to call me back outside.

Our Book Review Corner: “The Indestructible Houseplant,” by Tovah Martin


by Catherine Feldman

I just read Tovah Martin’s “The Indestructible Houseplant” and I am happy to announce that I have discovered a new outlet for my Plant Gluttony. She endorses full-green-immersion-indoors, and that sounds like a good goal to me!

I have always kept my houseplants to a minimum, because I like to leave my plants to do their thing without too much fussing on my part (Garden Sloth Method.) Most of my experiments with houseplants have not fared well due to that approach. Now, I have discovered (and I hope, you will, too) a host of houseplants that can take a fair amount of neglect, yet provide much pleasure to the eye and soul.  Winter is taking on a whole new cast! She encourages us and shows us how to have gardens, forests even, in the house. Inside could reflect the outside. Think of the beauty, clean air, and sense of relaxation! I can’t wait. Recommended.

Extra tip: Watch how she combines plants with containers. That’s the magic.