FIMBY: Soggy soil and what to do about it
This is another installment in our Food in My Back Yard series, devoted to edible gardening.
So here we are, in a long stretch of foggy, damp days, with flat gray skies. It hasn’t rained since before Thanksgiving, yet everything is still so … wet.
The leaves are damp, the air is misty, and the soil — especially any clay soil — has not dried much since the rains, sticking together like wet adobe for bricks.
Clay’s moisture-holding property is valuable for our gardens, keeping roots nourished during our hot, dry summers. (Remember those?)
But now, under these weather conditions, that clay seems like it will be squishy forever.
Here are some things to do and not to do with your saturated soil:
— First, don’t walk on or roll anything heavy across planting areas. Stick to paths or stepstones. Walking on wet soil compacts the soil’s pore spaces, squeezing out oxygen, which plants’ roots need for growth. The compacted spaces don’t pop back like a sponge — they stay squished or absent. Roots are prevented from spreading. And any subsequent rainfall or irrigation has no place to go, pooling at the site or running off.
The University of California Integrated Pest Management system calls this situation “aeration deficit.” They warn, “Insufficient soil oxygen, excess soil moisture, and root decay pathogens often act in combination to damage or kill plants.” This can include trees, too, though that may be a slow process.
In severe cases, anaerobic soil will smell like rotten eggs and/or have a blue-gray cast.
— As a corollary to this, don’t dig in saturated soil, either. This also will affect the structure. If you have plants that need to move out of their nursery containers, transplant them temporarily into larger containers, then plan where they will go in spring.
— If you have summer plants such as tomatoes that are finally finished, lop the stems or stalks off at the soil line, without disturbing the roots and the soil microorganisms.
— Take note of where garden drainage needs improvement. This long after rain, puddles or sticky muddy spots should not be evident in the garden. If they are present, it’s a signal that the site has poor drainage, and most plants will struggle there.
— Mulch, aged compost or worm castings can be spread on the soil now, but don’t dig it in under these wet conditions. (And keep it away from stems or tree trunks.) These toppings will eventually work into the soil, improving it. Additional soil amendments can wait until preparation for spring planting. Put reminders now on a 2026 calendar.
More information on soil problems and soil improvement can be found at these websites:
— UC IPM page on aeration deficit.
— UC IPM on providing for roots.
Napa County master gardener Janice Mathews has an excellent recent article on healthy soil in the Napa County Times, which is carried by our mutual portal, California Local. Find the link to her article on the left side of the home page.
