In the winter time, a couple of my garden beds get less sun and stay more soggy so it’s difficult to grow a food crop. I usually let the soil rest at this time, but by that I don’t mean I leave the garden beds bare.
Even if you only garden three seasons out of the year, you should never leave the soil exposed and empty. Winter rains could lead to soil compaction, especially in hard clay soils. The ground could become eroded and the nutrients washed away when there are no plants and roots to reign them in. Some people simply throw a layer of mulch on the ground and call it good. I like to grow a cover crop — and I especially like to grow fava beans as a dual-purpose cover crop.
As a legume, fava beans fix nitrogen in the soil; that is, they put in more nitrogen than they take out. As a cover crop, they improve the soil texture, suppress the weeds, support microbials in the earth and they’re even edible to boot. They are the gift that keeps on giving. Even if you don’t have the patience to shuck fava beans, even if you don’t like the taste of them… you should grow favas, and you should get them in the ground this month.
Fava beans (Vicia faba, also called faba beans or broad beans) are actually not a bean but a type of vetch, a common cover crop and forage crop. They germinate quickly, thrive in cold weather and tolerate shade. They require minimum watering in winter, especially in wetter climates. With proper mulching, I only give my favas an inch of water a week, and sometimes less if we’ve had rain. The leaves are susceptible to rust, an airborne fungal disease, so keeping them airy and dry is important.
Though it’s not necessary, you can soak fava bean seeds for a few hours to speed up germination. Sow the seeds about 6 inches apart and 1 inch deep. Sprouts will appear within the first week, and grow into 6-inch seedlings within a couple of weeks.
Favas are tall, thin, and top-heavy plants that usually require staking as they mature. They grow up to 5 feet tall and produce clusters of beautiful, orchid-like flowers. These flowers turn into dense green pods that sometimes reach 8 inches long or more.
Once you’ve harvested all the beans, you can prune the plant back to just a few inches above the ground; I’ve trimmed mine down to 6 inches, cutting just above the leaf nodes. This vigorous haircut, although a little scary at first, encourages new growth and you may get a second harvest of beans in the same season.
In spring, after the last of your harvest, cut down all the plants but leave the roots to rot in situ (so they release nitrogen back into the soil). At this stage, the stems are too woody to dig into the ground (as green manure), so I simply compost them.
You can also plant another fava crop in spring and repeat the process. Throughout the year I’ll stick a few fava seeds in the ground wherever I have an unused patch of soil; even if I don’t let the favas grow into fully mature plants, their roots feed the rhizobia (soil bacteria), which work with legumes to fix nitrogen. If you remember to rotate legumes (including peas and pole beans) among all your beds, you can continually nourish the soil without ever adding fertilizer!