Thanks to the abundant and late rains this year we ended up with quite a few fields that we were unable to plant during the spring, either because they were too wet when we needed them or simply because we ran out of time to get them planted for summer.
We don’t generally like to let fields sit very long unplanted.  And yet after mid-June, it’s basically too late for summer crops and too early for fall ones.  But we have found that this two-month period up until mid-August is an ideal window to grow a summer cover crop of leguminous cowpeas.
We grow cover crops to feed the soil so that the soil can feed you.  In this case, the cowpeas grow quickly and vigorously, fixing nitrogen from the atmosphere in their roots.  The lush, viney plants shade the soil from the hot sun, smother out weeds, and aerate the soil with their deep roots.
Because it is summer, the cowpeas need water to grow — but not much.  We typically irrigate them only twice.  By the time they start to run out of water, they are often waist-high.  At that point, we plow them back under — harvesting nothing at all from them.  Then we let the residue decompose for a few weeks before planting a fall or winter crop.
Cowpeas after mowing (left) and before (right)
We don’t have enough land or time to grow summer cover crops on all the fields before they go into a fall crop, although we wish we could.  The crops that follow the cowpeas are almost always the nicest we grow.  So we try to make sure to put our most important crops in those fields. For example, strawberries — which we plant in late August — always follow cowpeas.
For several years now we have also tried to grow cowpeas in the fall on the fields that are scheduled for planting in early spring, such as potatoes and tomatoes.  These fields need to be “almost ready” when the rains start, so we can’t grow winter vegetables on them.  And because the cowpeas are a summer crop, they wilt and die once the weather gets cold.  That makes it easier to prepare the field in mid-winter in between the rains.
Right now we have several fields of summer cover crop in various stages of growth, and we are planting the final rounds that are destined for the first tomatoes of 2018.  Once we wrap that up, it will be time to start planting our fall vegetable crops.
Thanks,
Pablito