Winter is a time I think about being cozy and doing some restorative work on myself. Daily stretching, face masks, lots of sleep. Surprisingly, your garden desperately wants the same kind of self help, and providing that help to your soil is as easy as doing a little detective work this fall.
It’s easy to think of soil as mere dirt, but it’s so much more complicated. If you garden, both the structure and nutritional content of your soil is the most influential factor in the success of whatever you plant. You want rich soil with good drainage, but the ability to hold onto some moisture. It should be just sandy enough for great root growth, but too much sand won’t have enough nutrients for most plants. It should be rich in nutrients, but not too much of any particular nutrient or else it will send the wrong message to plants.
Start with a layer of compost
The solution is three-fold. First, every fall you want to top-dress your beds with compost. Not all compost is created equal, so if you’re not creating your own compost, don’t just dump horse manure in your yard. Choose compost that has been tested and is well broken down. It doesn’t have to be expensive—I use city compost and am quite happy with it.
This top dressing helps restore nutrients, but it also helps restore volume of your bed, since your soil becomes compacted over time and you lose some to erosion and as you pull out plants each year.
You’re not using enough mulch
People simply don’t use enough mulch. Mulch is natural insulation, so it will keep your bed soil at a more moderate temperature with less fluctuations, and it helps retain moisture in the bed. That means less damage from heat domes and freezing. In fact, for years I used to take my largest outdoor potted plants and just bury them between the rows of berries under two feet of mulch, and they were fine.
Once you’ve composted, if you don’t intend to use a cover crop, mulch your beds with a few inches of chips, leaves, or straw. If you’re going to plant a fall crop, just pull away the mulch, plant, and keep the mulch away from the stem of the plant.
If you’re not planting a fall crop, plant a cover crop
A cover crop is a seed you broadcast (similar to how you plant grass, densely) that will grow over winter. Come spring, you’ll hack the crop down and allow it to compost in place, either by tilling it in, or by flattening it and covering it with plastic. Not only does this cover crop provide rich nutrients back to the soil, but a number of cover crops can solve really specific problems with your soil.
If you have compacted soil, oil driller radish (a form of daikon) will break it up. If you have a lot of weeds in your bed, plant winter rye. If you had heavy feeder crops in the bed this summer, like corn, which needs a ton of nitrogen, plant hairy vetch or fava beans to replenish the nitrogen levels. If erosion is a problem, white clover will keep your soil safe this winter. To alleviate pests, plant mustards, and if your soil could use more humus, plant cowpeas.
Your local nursery will have bulk cover crop seed and can help you figure out what would be best for your beds. This is an inexpensive and highly effective way to amend the nutrients and bring your soil back to health.