By Farmer David Plescia of Green Valley Community Farm
"Grow healthy soil. The rest will follow." -Unknown
Going into this year, Kayta and I really didn't know what to expect from Green Valley's soil. How would the veggies look throughout the demanding growing season?
Not all soils are the same. Some require much more work out of a farmer than others. Very sandy soils, for example, require farmers to focus much more on the nutritional side of things, as nutrients leach out of sandy soils. Very clayey soils are more challenging to create and maintain healthy soil structure. The "Goldilocks" loams found in places like California's Central Valley and the Great Plains, built up by eons of carbonaceous plant activity, are described as "boy's soil" -- in that you don't have to do anything to get stuff to grow.
Going into this year, we had heard rumors of tougher growing conditions here from the previous farmers: Occasionally stunted plants, discoloration, etc. Our soil tests in the fall of 2016 indicated that with some standard amending (lime, for example, as Sonoma County soils are usually slightly acidic) the "clayey" sandy loam here had much of what happy fruits and veggies need. We could only do our best and see how the plants grew...
To establish a good baseline here, Kayta and I did some pretty textbook organic amending, based on our soil tests, to the fields and garden in the Spring. We added oyster shell lime and gypsum (to balance the PH and add calcium), sulphur of potash (because the soil was lacking in potassium), bonemeal (for phosphorus), feather meal (for nitrogen), and hefty amounts of compost to add organic matter; the glue of all soil biology and chemistry. If a bed was planted a second time this Summer, we added a small amount of feather meal and bone meal.
We were thrilled to see that this relatively modest treatment, combined with the native soil composition and biology here, yielded very healthy plants... even some super phatty cauliflower and broccoli heads (a good litmus test of soil fertility.) There were ample earthworms and mycelium (fungal networks). Roots and crop residues broke down very quickly, indicating vigorous soil biology.
All this is exciting. It means that each year, as the PH and nutrients are balanced, we can rely less-and-less on these outside inputs and more-and-more on closed loop, multi-functional systems like cover cropping, rotating livestock on fallow fields, compost made from farm waste, and the soil biology built from these practices. As we speak, the thick leguminous cover crop sinking its roots into the soil out there should, among other things, provide most or all of the nitrogen we need next year for phat cauliflower heads. The clayey nature of this soil means that nutrients and organic matter will be retained by the soil, those small particles hugging them tight. The soil should only continue to improve by years of thoughtful management and care.
It's not "boy's soil" out there, but we're all lucky to have fertile little Green Valley.