Creating Pockets of Fertility

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An experiment in quickly creating patches of deep, abundant, living soil and long term fertility in the organic garden.

I had a serendipitous moment this morning. It was still pitch dark outside, but I woke up and couldn’t go back to sleep, my mind was churning away at all sorts of stuff, some important, some annoyingly trivial (WHY am I awake again?). But ultimately my roving brain pulled together a few puzzles out of the nether and tied them together: there were some buckets of food scraps that needed to be dealt with, some seedlings in soil blocks that probably wanted to get started in real soil, and a bunch of information on soil, fertility, nutrient cycles that I wanted to put to use. All of that suddenly synergized into a darn good little idea. Fertility pockets.

First some background.

A while back my mom and I were talking about how we dealt with compost. At the time I was all pumped on aerated compost and how it was possible to create a real rich compost in less than three weeks (which involves almost daily turning). She thought it sounded interesting, but said she was going to stick to her method which was to simply throw her food scraps in a hole in the ground for a while then cover it up with soil when the hole was full. She said that it broke down remarkably fast without much effort on her part. I tried the aerobic compost route and did in fact achieve a nice rich compost within a month. But the process always felt….off. It was awesome to create soil so quickly, but I knew that with each pile turn I was exposing all these microbes to the air which were then going on a feeding frenzy and drying out, dying, and releasing who knows what into kind of carbon into the air. Then what happens with this compost? It usually gets top dressed onto soil of lesser quality. They call this feeding the soil…and to some extent it is, but what a waste! Here is this unbelievably rich soil that has been created, and it gets thrown on top? The most precious part of that soil is the amazing amount life that is now living in it. By throwing it on top, the moisture and rich life will die off, killed by sun and eroded by wind. So in the back of my mind the aerobic, compost turning method seemed to have it’s own set of issues, on top of being time/energy intensive. Without adequate moisture and mulching, that effort of creating such beautiful thriving soil simply goes to waste.

To go a little further into the moisture story, I want to pass on one of the most fascinating stories that I heard recently. I heard it at my advanced permaculture design course in July with Robyn Francis. I THINK this was work that Robyn Francis was part of. In India recently they did a special planting method for a forest plantation of various trees. The method was to dig the hole for the tree, fill the hole with water, let the water soak in, fill the hole with water a second time, let it soak in again then plant the tree and (if I remember correctly) water it in. I’m not sure how heavily the trees were mulched with organic matter, but I do remember the area around the tree was mulched with rocks which would capture moisture from the air. That region was hit by a pretty severe drought that year and the trees were not watered at all beyond the initial planting. However, they only lost a handful (literally) of trees from among thousands. Between the mulch and the moisture already embedded in the soil from the double deep watering, the trees had enough to survive.

So, right, back to these buckets of goopy, stinky food scraps that I had collected from a downtown vegan restaurant. The scraps were intended for worm bins at Veggielution, but for a while now the worm bins have been overloaded and pretty foul smelling. So I needed to figure out a way that I could use these food scraps while Veggielution volunteers built a couple more worm bins. So this morning I realized that I could use all of that concentrated, nutritious goodness to create little areas of abundant fertility within my garden, which I am calling Fertility Pockets.

They are nothing complex, nor really anything new, but when I see how they fit into the grand (hah) scheme of the garden, I think it is an elegant solution that requires a one time soil disturbance with long lasting rewards. The basic method is to dig a reasonably deep hole, take a nutrient soup, (like the buckets of food scraps, or anaerobic buckets of compost that have been fermenting in their own juice, yum!, or possibly the weeds that you have submerged under water to kill off), and fill the hole with layers of soup, carbonaceous material and soil (a layered compost basically) and cover the hole with the remaining soil. This will form a small mound which should be planted into immediately with something that would enjoy a rich bacteria-dominated soil (I used kale and broccoli).

This Fertility Pocket method is an experiment and might have some unexpected results, but based on a lot of reading and observation of soil in my own garden here is what I expect to happen. By filling a hole with organic matter high in moisture content and nutrient rich water, in most soils this moisture will very slowly leach out over time. This water that drains into the surrounding area will be high in nutrients and organic matter. The organic matter in the hole will slowly decompose over the following months, functioning as a time release fertilizer and creating an abundant, deep, moist, living soil. The layering of organic matter and soil distributes soil microbes evenly throughout the hole and creates aeration so the soil can breath. As long as this soil is not disturbed and is well shaded by plants and/or mulch, the nutrients will continue to cycle between the soil and the plants who will eagerly send their roots into the newly created treasure trove. By doing just a modest hole, rather than say a double-dug swath or a rototilled patch, this allows everything around the hole to remain undisturbed. Mycelia, microbes, worms and plant roots can all start to move in as moisture radiates out and as nutrients are broken down and made available.

Here was the process I followed this morning:

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I dug about a foot down and hit a firm layer of rocky sub-soil.

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I widened the hole from there until it formed a rough bowl that would hold two buckets worth of soup plus some layers of soil.

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I threw some weeds in down at the bottom to decompose. The bottom of the hole is probably going to be pretty anaerobic for a week or so (just a guess) and it is deep enough so that even if the seeds do not rot away, they are too deep to surface.

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I poured some food scraps on top of the weeds and added a layer of soil. The soupier the better for this part I think.

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Added dried out corn stalks and dried grass and other carbon rich stuff.
Added another layer of food scraps (by now the mixture was pretty much a stinky bowl of mud soup) and the rest of the soil

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The remaining soil should form a mound. I planted garlic chives, Egyptian walking onions, broccoli, and kale into the mound. The annual brassicas are for immediate capture of whatever nutrients are readily available, the chives and onions will stick around to anchor the soil while I decide what other perennials to add to the mix. I am not too concerned about nutrient lost though, because there is a neighboring maturing broccoli and fruit trees that will probably send their roots over to check out the moisture and the nutrient cocktail.

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As a final touch I threw small handfuls of Azomite down to add additional nutrients and trace minerals. Since this is not a renewable source of fertility, I put it at the top to be watered in over time. My hope is that as the plants and the soil organisms kick into gear they will trap most of these trace nutrients and prevent them from leaching beyond the pocket.

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Overall the process took me less than 45 minutes and it could have a positive payout for years, especially if the soil remains undisturbed (no tilling!), mulch is added as a top dressing and perennials are planted into the pocket after the broccoli harvest. If I plant a perennial polyculture around the pocket, the nutrients could cycle within that small ecosystem indefinitely. I’ll be doing a few more of these in the garden and will report back on the results after the pockets have had the chance to break down and the plant patches mature over the following year.