Soil Building Basics 1: Keep The Soil Covered
Minding your own patch of this planet by nurturing your soil and building humus (sequestering atmospheric carbon) is the ultimate win/win. It benefits the gardener, the garden and this practice regenerates the precious medium that sustains us all. In fact, it may be your most powerful contribution to the greatest challenge we will ever face.
~ Graime Sait
The world underground beneath our feet is amazing and complex, teeming with life and intelligence that we are just now beginning to understand. Yet despite the complexity, the methods for building and maintaining the soil are relatively simple. We can be stewards and participants in that soil ecosystem, working alongside the land as partners instead of contributing to degradation over time. Over the next few weeks I’ll share a few principles for building soil and soil carbon (aka: resilience) which can happen right in your backyard. These principles are adapted from the US Natural Resources Conservation Association (NRCS) Principles on Soil Health.
Principle #1: Keep the soil covered.
Armor the soil surface with mulch or living plants. Keep it protected from the elements for as much of the year as possible. Bare soil that is exposed to the sun, wind, and rain will oxidize and release it’s life-giving richness (soil carbon) to the sky. Keep it covered, cool, moist and alive.
Get creative with the idea of “mulch”. Mulch could be shredded leaves, hay, buckwheat hulls, straw, chopped up weeds or groundcover. It could be wood chips from the neighborhood tree chipper, rice hulls, animal manures from the zoo (yes, that is a thing!), washed up seaweed on the beach, leftover substrate from mushroom production, twigs, cut grass, shredded paper, cardboard, cocoa hulls or pine needles. It could be a crop you grow, then chop down to dry on the surface. I even saw a garden that used old wool (wool that wasn’t a high enough grade to spin into yarn and would have gone to the landfill) to cover the soil - the result was incredible! Mulch not only suppresses weeds, but feeds the soil microbes a source of carbon. It jumpstarts the soil biology to start cycling nutrients and make them more available to your plants. In this case, mulching is actively feeding the soil which then goes on to feed your plants.
Once you start feeding your soil microbial workforce, you will start to notice it is HUNGRY. Ready for more “food” to cycle more carbon, grow more plants, build more soil! So once you jumpstart this regenerative, soil-building cycle, make sure you follow through. Keep feeding it.
If this sounds like a lot of work, it can be in the beginning, especially with a heavily degraded site. Yet as the system grows, so does that capacity of the system to provide what it needs. Life creates conditions for more life. You have an amazing ally in your work to support the soil that is growing all around you: plants.
What if plants could grow all this much-needed mulch for you! They want to participate in the wholeness of the system. They grow beautiful big leaves that fall to cover the ground and protect the soil. Isn’t that amazing? You have built-in mulch suppliers. All you must do is just watch, be creative, find those nutrient flows that abundantly come off the landscape and reinvest them into the soil. For healthier, more lush plants. For more resilient landscapes.
You could even use stones as a mulch. True, that they won’t feed the soil in the same way other woody or carbon-rich materials do, but they do keep the soil covered and protected. In hot, dry environments that residual heat can sometimes even condense tiny amounts of water from the cool morning air to add just a few drops of much needed moisture to the plants beside them.
And plants themselves provide an amazing cover! What are native groundcovers in your area that naturally grow and spread and bloom like a green carpet in pathways, garden or forest floor? Take inspiration from the landscape around you.
I like to use peas in my garden as a plant cover. I buy “field peas” in bulk from farm seed suppliers and grow them very thickly in springtime. Fresh pea shoot greens are an excellent “cut-and-come-again” crop in the garden. I try to keep up with their enthusiastic growth by cutting them often for fresh eating in salads, sauteing them in stir fries or adding them to soups and curries. Once I can’t keep up with them or they start to get tough as the summer heat, I either let them grow to re-seed themselves for the fall or, if I want the garden to look particularly clean and well-managed, I can chop them to the ground. I leave roots in place to break down over time and sprinkle the roughly chopped up leaves on top of the soil to dry out as my very own homegrown mulch. I can plant my summer tomato seedlings or eggplant directly into this light mulch. This is just one example of a backyard “cover crop” - a plant grown (often inbetween main crop plantings) to build the soil.
Any plant, really, could be a cover crop. Though farms have their favorite plants to use: plants that fix nitrogen, outcompete weeds, drive out pests, remove pathogens, build soil structure, protect waterways from excess phosphorus and nitrogen, support pollinators, provide fodder for animals or plants that break up compacted soils. These plants are truly superstars on a farm.
In summary, keep the soil covered. Be creative about it. Notice the difference of covered vs. uncovered soil. Don’t take it from me, but see for yourself on a hot day what the soil feels like when it’s protected, cared for, and treasured for the true miracle it is.
For more information on NRCS Principles of Soil Health, check it out here: https://www.nrcs.usda.gov/wps/portal/nrcs/detail/nd/soils/health/?cid=nrcseprd1300631