How and Why to Grow Good Soil
A bad gardener grows nothing.
A good gardener grows crops.
But a very good gardener grows soil.
—Japanese proverb
Gardeners call it black gold for good reason. Rich fertile soil is the keystone of a healthy garden. It produces robust and disease-resistant plants that produce food full of flavor and nutrition. Eating this food makes YOU robust and disease-resistant. Fertile soil is able to hold and recycle nutrients over and over, making your garden more productive as time goes on. Recycling soil fertility is particularly crucial when you are gardening in a limited space. It's not like you can dig up your neighbors' yard when your soil is exhausted. For a truly sustainable way to grow food, you need to grow soil that replenishes itself.
Why do I need to "grow soil" anyway? What about the dirt in my yard?
If you live on an urban or suburban lot, I'm sorry to say there's a high probability your soil is in pretty dismal straits. See, at some point before your house or current abode was built, the ground was levelled. The good topsoil was dug out, trucked away, sterilized, and sold in bags of “garden topsoil.” Yep, that’s right. Some company extracted the black gold from the earth, made a few dollars on it, and now you're just supposed to drive on over to the big home improvement store and buy that same soil? It's absurd, and also true.
Don't be a stooge. Fight the power. Making your own good soil is right up there with saving seed as an act of peaceful sedition. With all the chemical companies, organic fertilizer makers, and self-proclaimed experts out there vying for your attention and money, deciding to DIY your soil is an act of defiance and self-reliance.
Be sensible.
I want to emphasize right up front that I'm advocating for simple, practical, and very inexpensive ( mostly free) ways to improve your soil in the ways that count nutrient levels, microbes, tilth (a nice workable texture), and ability to filtrate water. That's what you need for robust plants and good harvests. I'm here to show you exactly what you need and nothing you don't.
Because if you Search for “How to Improve Soil” or “How to boost soil fertility” you are going to get a few articles and a whole lot of advertisements. This miracle product versus that one. Not only is it bewildering it’s also very pricey. Even if you dismiss the chemical products, the “organic fertilizer” and “natural amendment” dealers can be just as pushy.
What are they pushing? Well, their products of course. First, you have to buy a test for your soil. Granted, the test is not expensive. Then you are advised to amend your soil based on the test result--with the products they incidentally sell, some at eyebrow-raising prices. They may also recommend guides that inform you which plants require more of each nutrient so you know exactly how to feed the soil for each and every plant.
First of all, this is too complicated for me--and most busy people I would think. Not to mention expensive. It’s a real turn-off to gardening in general. Here you are in the garden, trying to connect with nature damnit, with your test results and reductionist formulas for what input goes where. Do you really want to spend your time outdoors with little containers and baggies of kelp and powdered blood, dressing each part of the garden to specific requirements, like a nurse administering pills to hospital patients?
Besides the cost burden and time-consumption, the real issue I have with specific soil prescriptions is that they aren't regenerative--and therefore unsustainable. The soil amendments recommended by organic gardening guides might be natural (bone meal, blood powder, dried kelp, greensand, etc) but you still have to buy them and they are obviously either highly processed, animal by-products, or extracted from riverbeds and oceans. Sure, these soil boosters come from nature, but it is really wise to set yourself up to depend on store-bought inputs? What happens when there's a lockdown and you can't get to the big box store for your soil stuff? Or when your city's power grid fails? As we now know, the line between life as usual and life changing circumstances is quite thin.
Use Your Senses!
Ok, so if I've dissuaded you from buying unsustainable soil amendments, what now? You still have this poor quality soil and you really want abundant harvests of food.
First of all, if you have a good reason to test your soil--potential heavy metals, for example--by all means do so. If there's little danger of lead or toxic substances in your soil, you can test it yourself. Next time you're outside (on a nice day, scoop up a little earth. Now, use your senses!
Look
Is it reddish brown or gray?
Touch
Rub it between your fingers. Does it feel dry and powdery or wet and slimy?
Smell
Does it smell rank like ammonia? Or does it have no smell at all?
Healthy soil is dark brown to black in color, slightly moist to touch, and emits a rich earthy smell.
If you answered yes to any of the questions or your soil doesn't fit the description, you need to add organic matter.
Now, here's what you can't see: One teaspoon of soil holds a billion bacteria, millions of fungi, and thousands of amoebas in addition to clay, sand, silt, water, air, and humus (mostly decomposed organic matter).
Soil enriched with plenty of organic matter can hold up to a hundred times as many beneficial organisms. An acre of soil can easily host four tons of worms, ants, millipedes, and mites, a construction crew of soil-builders.
Soil grows because it is pulsating with life. As the inhabitants of this lively underworld carry on their business of crawling, eating, excreting, and dying, pieces of organic matter in the soil (mulch, fallen leaves, pulled weeds) are broken down into nutrients for your plants. Organic matter in soil doesn't decompose by itself--It is digested.
Also, this naturally occurring system is more efficient than anything we’ve devised in a bottle. Plants can access nearly all of naturally occurring organic matter digested by soil organisms and converted into nutrients without wasteful or toxic by-products. Feed the tiny animals in the soil and they will feed your plants--not only once but continuously.
Ok, ok...you got me. But how???
Even the poorest of soils can be improved. My favorite example of this is terra preta, recently examined deposits of rich black fertile earth dotted throughout the hard red clay of the Amazon basin.
Because terra preta is always found accompanying millions of pottery shards, lumps of charcoal, and other signs of human habitation, archaeologists and soil scientists agree: Terra preta de indio literally is "the black earth of the Indians." They didn't find it already there. They made it.
The first terra preta deposits likely began as "garbage" piles. Amazonians heaped up kitchen waste, bone, and excrement with palm leaves and other vegetation. To reduce the size of the piles, they burned them in controlled smoldering fires. The smolder produced chunks of blackened organic matter called biochar. Today, soil scientists are studying and documenting the remarkable abilities of biochar to hold nutrients in soil. The forest inhabitants likely based their conclusions on observation. They noticed that the seeds germinating in these smoldered piles grew into bigger healthier plants. Hmm, let's keep doing that and see what happens...
The existence of terra preta is much more than esoteric history. It has exciting implications for regenerative agriculture today. Terra preta is an outstanding example of how careful human intervention can improve soil fertility, in contrast to extractive farming methods that destroy it. The techniques that produce terra preta are relatively simple, accessible, very inexpensive, and often free. Anyone from the backyard organic gardener to the large-scale regenerative farmer can do it. And, as we have found repeatedly over the past four years on our land, they really work.
How to Grow your own terra preta
Make Compost
The first terra preta deposits likely began as "garbage" piles. Amazonians heaped up kitchen waste, bone, and excrement with palm leaves and other vegetation. They noticed that the seeds germinating in these piles grew into bigger healthier plants.
Now that might sound a bit messy. Illegal even. Don't worry, you have options. You can buy finished compost at a nursery or home improvement store to get started. But that's going to get expensive. For the long haul, you're better off investing in a compost bin where you can deposit all your banana peels (potassium), egg shells (calcium), veggie scraps (nitrogen), and leaf litter (carbon) and make a nutritious home-made meal for your soil critters.
Add manure
My dear friend and guest contributor Kristina Maze gardens in a tiny backyard on a crowded block of row houses in Washington DC. Every year she shovels a few sacks of free horse manure from a local park stable and feeds it to her garden soil. No one has ever said a word against it--aged manure mixed with straw won't have much of a smell. It only sounds hardcore until you do it. Your garden will reward you big time.
Fire it up
In addition to kitchen waste and poo, the key ingredient in terra preta was charcoal or charred wood. Amazonians burned their waste in low temperature controlled fires. Because these fires smolder rather than burning hot, essential carbon is retained in the soil instead of going up in smoke. The resulting "biochar" boosts long-term soil fertility because it binds with soluble nutrients that otherwise wash out of soil before organisms can get them.
To make your own home-scale biochar, you will need a fire pit or ring. Add your blackened chunks of wood remaining directly to your garden along with lots of composted organic matter. You can also add the ashes as a soil booster, but they do not hold nutrients in the same way biochar does.
Spread Mulch in Your Garden
Thick mulch is good for suppressing weeds. A generous layer of organic mulch also provides food and cover for crucial soil critters. Worms tunnel up to the surface to chomp on moist bark chips, straw, or leaves, creating aerated spaces in the soil and leaving their nutrient dense casings for your plants. Millipedes slither through it, chewing on leaves and excreting humus. Fungi and bacteria dine on the remains, boosting fertility even more.
Note: You don't have to buy mulch! Most towns and cities have free leaf/yard waste pickups and landscaping companies are often glad to drop off huge amounts of tree clippings for a small delivery fee. Plus the mulch you will get from a leaf pickup or arborist is going to be more diverse, and therefore better for the soil biome than those uniform wood chips from the home and garden center.
Mulch also protects your soil from wind erosion and prevents nutrients from being washed out by hard rain. Remember, bare soil is bad soil.
Chop and Drop
Soil organisms are opportunistic scavengers and will eat anything in the garden you don't. Not all the nutrients plants take from soil goes into the parts we eat. The stems, foliage, and root hairs are all excellent food for soil life. When you harvest vegetables, don't "clean" the "debris"--the carrot tops, squash leaves, or cucumber vines. Sure, you can put it in the compost bin, but it's easier to complete the cycle by chopping it up and leaving it on the soil. Your crew of soil-building insects will make short work of chomping it down into digestible nutrients and your remaining plants get a noticeable boost.
For larger scale farms and regeneration projects like ours, chop and drop is the most accessible of these methods. It is a cost and labor effective way to "tidy up" rampantly growing vegetation by simply slashing it back and leaving it on the ground or piling it up around the bases of target species trees.
Cultivate Diversity.
Finally, even the soil scientist types are starting to agree on one important thing: the plants growing in soil are just as integral to the health of the soil is to the health of the plant. Grow plants of different sizes, root depths, nutrient needs, and types of foliage, fruit, and seeds. A diversity of plants will work in myriad ways underground to build soil fertility by feeding microbes, interacting via sugars and enzymes, and networking with fungi. Plant an exuberance of life and yield an abundance of benefits for you and the soil.
Why it matters
Last year, the UN reported that over a third of the world’s soils were in a state of declining fertility due to extractive farming, chemical herbicides, insecticides, fertilizers, and deforestation. Regenerative gardens grounded in living soil are a practical way you can resist and undo this alarming trend. A regenerative garden builds resilience and self-reliance for both garden and gardener. If we are willing to learn from our own past, we can still salvage our future.
Related post: Here is a step-by-step guide to Cheap and Easy Ways to Build Healthy Soil
At Sueño de Vida we work in a meaningful way to heal land ravaged by deforestation. How meaningful? According to a recent UN Foresight Brief on climate change,
--It is of the utmost importance to stop deforestation and to increase reforestation efforts around the world. Agricultural practices should focus on soil building, year-round soil cover with plants and the use of agroforestry methods.
That is exactly what we do here at SdV. You can help by helping us do what we do every day: plant forests that nurture soil, people, and community.
Click HERE to donate directly to our reforestation fund OR make a monthly pledge on our Patreon.
Thank you.
Kristen Krash is the director and co-founder of Sueño de Vida, a regenerative agroforestry farm, education center, nature reserve in Ecuador’s Chocó Andino Cloudforest. Prior to moving, Kristen was known for her guerrilla gardens — productive green spaces she created in any available space. Now an urban transplant in the South American rain forest, she has adapted her urban gardening and sustainability skills to large-scale reforestation of degraded land. She takes a practical and accessible approach to helping others achieve more balance and self-sufficiency in their lives.
Kristen’s articles and interviews have been featured on popular sustainability platforms like Abundant Edge and The Mud Home, and in the Rainforest Regeneration Curriculum at the Ecological Restoration Camps.