The San Francisco Bay Area’s rainfall pattern and quantities vary widely from one year to the next and from month to month. See Weather Link for details. This creates some opportunities and challenges to gardeners and the landscape industry. In this region, regardless of your micro‐climate conditions, it is possible to plant, grow and enjoy a variety of food crops and ornamental plants, year round. A simultaneous opportunity and challenge is timing when you plant something to take advantage of the rain softening effect on soil to make the job easier, without taking the risk of working soil that’s too wet.
Due to the clay content of many soils in the region, a challenge for the landscape industry (and the home gardener) is constructing landscapes and installing planting plans without damaging soil structure. All soils, except sandy structured ones, are susceptible to soil compaction while wet and even dry soil can be affected. It’s the clay soils, however, that risk the chance of being permanently damaged structurally, if worked while too wet. In this case, degree matters. Clay soil needs to be moist to be workable at all (especially with hand tools), but if too wet, even walking on clay soil can severely compact it. This often leads to nutrient‐rich, clay soil being hauled away and replaced with sterile imported soil, adding cost to a project and creating less sustainable plantings in the long run.
This winter’s early and significant rains have made the last four weeks or so, an ideal time to “work the soil.” It’s been moist, but not too wet. There are things you can do to protect soil as you take advantage of this time. Mulching with a thick layer of wood chips is protective to soil, as is temporarily laying down plywood or other broad expanses of stiff material to walk on adjacent to the areas you are working. This disperses your body weight, lessening the risk of compaction. Our rain pattern is predicted to change over the next week. Working with the pattern, instead of against it has lasting (sustainable) benefits.