Tend Your Soil

Gardener’s Notebook

Photos courtesy of Joshua Burman Thayer. Top to bottom: The author in the rain with fava cover crop; fava bean seeds with scarlet runner beans and pole beans; winter greens.  

 As you clear out your fall tomato beds, take a little time to give some love to your garden’s soil. Then seed in some fava and garlic to grow through the winter months.
Safety First
If you’re preparing a new growing space at your East Bay home, you might want to bring in bagged soil with an OMRI (Organic Materials Review Institute) label showing that it has been tested and is free of pesticide residues.

If you’re farming right in the ground, a lab test to ensure soil safety can be a good first step. Tests cost around $70, and in addition to detecting harmful elements like lead and other heavy metals, they can also determine soil nutrient levels and pH. I recommend California-based Wallace Labs, which usually manages a one-week turnaround. They also offer a lab analysis of the soil profile, with comments from the lab technicians that explain the data in plain English.
Feed Your Soil
Organic farming requires that you make seasonal amendments to continue building good soil texture. Soil that is rich yet crumbly and aerated supports better plant health. One thing I encounter each week as a Bay Area horticultural consultant is people planting into hardpan clay without breaking it up and amending it. This leads to frustration with poor, sad plants. By amending your soil, you can ensure steady abundance.

Worm castings are a miracle food for your soil, although this amendment might seem pricey. I recommend broadcasting (scattering) one bag over 200 square feet. This light feed is pH balanced, so you do not have to worry about burning the plants. Manures are cheaper than worm castings, but they can burn plants if you do not broadcast properly, and you need to wear a mask since breathing in toxic steer and chicken manures can be dangerous. Broadcast one bag per 200 square feet.
Composting is just plain good for the planet. You can do it either in a compost bin or directly into your garden beds. Simply chop up all the non-woody and non-diseased leaves and stems to add regularly as a mulch around your plants. Another option is to make a mini trench at the edge of your raised beds where you can bury the crop residues and cover with garden soil.
Do the Wood Chip Boogie
Mulching with wood chips insulates the soil from temperature spikes. It also holds irrigation moisture and reduces weed growth. As the chips slowly break down, they support growth of mycorrhizae (beneficial fungi), which is very good for your soil. Most local tree companies can bring you six to 12 yards of free chips if you have a driveway where they can drop the pile. They’ll bring the chips within a couple weeks of when you put in your request. Make sure to state that you do not want any eucalyptus or sycamore chips, since these will poison your soil.
Cover Crops for Winter
Planting cover crops like fava, red clover, and arugula can benefit your soil in many ways. The crops can increase winter biodiversity, protect soil from compaction by raindrops, provide food, and support our local pollinators in winter when there are far fewer blossoms around to provide them with the nutrition they require.
Want to learn more?
Check out other articles in Joshua’s Gardener’s Notebook series in Edible East Bay’s newsletter and quarterly magazines. Of special interest is the food forest article in the Spring 2018 issue of Edible East Bay: Creating Layers in Your Food Garden
Joshua Burman Thayer is a San Francisco Bay Area ecological and permaculture landscape designer and consultant specializing in dry-land landscape design. He can be reached at 510.332.2809 or nativesungardens.com.