Annual Soil Building: An Organic Year in Review

Reader Contribution by Joshua Burman Thayer and Native Sun Gardens
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Photo by Pixabay/Wiselywoven

The season is wrapping up for the calendar year. That said, here in the sub-tropical Bay Area, we have a 365 days of growing opportunity. As we clear out our fall tomato beds and perhaps seed lava and garlic into the beds for winter, now is a good time to give some love to your farming soil.

Safety first: Test your soil. For those of you hashing out new growing space into your homes, it can be important to bring in O.M.R.I. labeled bag soil. When a bag of soil shows this O.M.R.I label, you know that it has been tested to be free of pesticide residues. For those of you farming the ground, a lab test can be a good first step, to ensure soil safety.

I recommend Wallace Labs. They are California-based and offer a 1-week turnaround. They also offer a lab analysis of the soil profile, as well as sentences from the lab technicians to interpret the data into regular human terms.

Note: A  lab test not only can detect harmful elements (ie.. lead and heavy metals) but also determine soil nutrient levels and the important pH of the soil. By spending the $70 on a test, you can get a jumpstart on assessing your soils current status.

Cover crop for winter. Cover crops benefit your soil in many ways:

Increase winter bio-diverisity (and food)
Protects soil from compaction from raindrop
Supports the pollinators in winter when there are far fewer blossoms around to provide nectar to native ecology.

Feed the soil! Organic farming requires the seasonal amendments to continue to build yummy soil texture. When it is rich, yet crumbly and aerated, soil can achieve exponentially compared to poor soil.

One thing I encounter each week as a Bay Area horticultural consultant is people planting into hard pan clay without breaking it up and amending it. Thus, they can get flustered with poor, sad plants.

Worm castings. By amending your soil, you can ensure steady abundance.  I recommend broad casting worm castings at the rate of 1 bag per 200 square feet. This light feed is pH-balanced, so you do not have to worry about burning the plants. Though pricey, worm castings is a miracle food that you cannot go wrong with.

Manures. Manures are cheaper than worm castings. However, they can burn plants if you do not broadcast. Also, you should wear a breathing mask, as steer and chicken manures are toxic to breathe in. Broadcast at rate of 1 bag per 200 square feet.

Crop residues. You can continue to compost in a compost bin or directly in your garden beds.  Simply chop up all the non-woody and non-diseased leaves and stems and continually mulch with them around your planted plants.

Another option is to make a mini trench on at the edge of your raised beds and bury the crop residues in the trench and then cover with garden soil.

Mulch. Wood chips are great because they can: insulate the soil from temperature spikes, hold irrigation water longer, reduce weeds, and break down slowly to support mycorrhyzzae (beneficial fungi) growth. Contact your local tree company and request 6 to 12 yards of free chips. You will need to have a free driveway and they may only give you a 2-week span of time to receive if free or cheap. Ask if there is Eucalyptus, Sycamore or Black Walnut (“Make you Sick-A-More”) in the mix — you do not want these species.

Joshua Burman Thayer is a landscape designer and permaculture consultant with Native Sun GardensHe is the Urban Agriculture Supervisor for Tenderloin Neighborhood Development Corporation in San Francisco, Calif. Find him at Native Sun Gardens and read his other MOTHER EARTH NEWS posts here.


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