As the cold season begins, the attention to the garden usually wains. Fall and winter, however, are some of the most important times for thinking about building soil health.
Soil maintenance and improvement is the cornerstone of any agricultural system. As Franklin Delano Roosevelt once said, “A nation that destroys it’s soil destroys itself.” As such, let’s go through a whirlwind tour of how to protect your soil during winter and how to initiate some strategies for fast-action soil improvement.
The garden plot pictured below constitutes part of the yard my parents use to grow food. The inputs to the system were only those which were readily available and mostly free. Remember, the exact management strategies and inputs you should use are dependent upon a host of factors including soil type and parent material, climate, pH, moisture retention, intended crops to be grown, and past use. In other words, there’s no universal strategy that’s going to work for every circumstances and, in fact, creative and novel strategies that respond to specific situations should be tried whenever possible.
STEP 1: REMOVE RESIDUES TO BE APPLIED LATER
The picture below is a soil bare and denuded-not a good situation! If left in this condition, the soil would be exposed to significant erosional processes over the winter; will likely become infested with weed seed; and is likely to have nutrient loss from mineralization and leaching of key plant nutrients. Like a wound, the vegetative cover and epipedon-the skin of the soil-has been cut away and is prone to loss of vital nutrients and infection. Thus, our goal is to speed up the healing process while directing the use of the soil to a sustainable surplus for human consumption.
STEP 2: APPLY NUTRIENTS
The reason why I’m using the amendments pictured below was because they are free (sitting in my parent’s basement). I would have liked to also include some long-lasting rock dust fertilizers. There are many gravel mines located nearby that harvest glacial outwash plains. I’m not sure how difficult it is to get “fines” (the dust fraction from the gravel) from the mines or how much it would cost, but this is a very nutrient rich and heterogeneous product that would be perfect for such application.
STEP 3: ADD RECALCITRANT CARBON SOURCE
Adding as many different types of carbon sources provides the soil food web with a diverse assortment of food sources. Some are like simple carbohydrates (sugar monosaccharides) that are rapidly consumed. Others are like more complex carbohydrates (cellulose polysaccharides.) Here I’m adding bark that was chipped off of cordwood when splitting wood for my dad’s soapstone stove. Some of the bark I soaked in a trash can full of water with a little bit of the mycorrhizal fungi added to innoculate the wood. I’m not sure that the particular strain of fungi will take to breaking down the cellulose/lignin. It’s probably good to have innoculant containing a host of fungal communities that are native the local region.
STEP 4: ADD SOME MORE CARBON
Next I add a layer of leaves to the garden bed. My dad had these all raked into a nice neat pile-great for the taking. And then I add some paper bags that were about to be recycled. Note that the thin layering of bags isn’t going to smother out weeds. If you’re goal is to mulch out weeds I recommend having a uniform and multi-layered cover preferably using cardboard which is nearly impenetrable. Lastly, I’m adding garden “waste”-the “trash” from a perennial sunflower provides another source of high-lignin microbe feed.
STEP 5: Cover with Rough Compost
The next step is to smother everything in a nice rich compost. I’ve got a good amount of somewhat rough compost (not fully decomposed) that’s been steeping in the backyard that I’ll use. It’s ok if it’s somewhat rough-it will break down over winter as leachate and microorganisms move down the profile to help break down the rest of the material. After applying the rough compost, I’ll again cover the whole bed with a layer of leaves to protect the compost from possible wind or water erosion.
STEP 6: Seed with Cover Crop
Just prior to adding the leaves in the previous step, I spread annual rye grass seed. The seed will germinate to produce a thick mat of winter hardy rye that will further protect and aggregate the soil together through the dense rhizome layer (roots). The rye grass should be killed before it seeds so that it doesn’t scatter unwanted seed in the garden. In order to do this you could simply chop or mow it down with a hoe or scythe and/or mulch over it with a thick layer of newspaper or cardboard.
STEP 7: Add Ash
We’ll be adding ash to this garden regularly as we burn through our wood pile. The ash will provide plant-available nutrients for the coming growing season.
Note that practically all things we just looked at are either fairly inexpensive or free. Most of the materials (save the store-bought fertilizer and lime, and rye seed) came right from on-sight and cost nothing at all (though having them hauled away may have). Systems can be changed, adapted, and regionalized based on your needs, climate, budget, and time. Most gardeners and farmers agree that regenerating healthy soil is incredibly rewarding and enjoyable. Best of luck!
-Ryan
Ryan Hottle has run several market farms, worked in a commercial orchard and is currently a PhD student at Ohio State’s Carbon Management and Sequestration Center in the Ohio Agricultural Research and Development Center.