As summer finishes and the rains threaten, it’s time here in Northern California to cover the fields. Cover crops are planted to protect the soil from erosion and to feed the soil life. They are planted ideally, at least once a year, in every field.
Many summer crops have finished producing; tomatoes, eggplant, peppers, melons. Once the drip lines, stakes and twine are moved out of the field, the vines and other crop debris are tilled into the soil. Because of a good 4″ rain a weeks ago, the moisture level in the ground is perfect and perfectly even. These conditions are rare and precious. The farmer is happy but needs time to do it all. Finally the cover crop is planted. We have a large planter that is pulled behind the tractor. You can tell from the picture above because the plants come up in nice straight rows vs. planted by hand where the plants would make an even blanket.
Some fields are left without cover. Those are the fields that dry out first in the spring, allowing us to use them for early plantings of carrots, lettuce, mache, whatever makes sense. The photograph under my blog name has been “bedded up” for early planting.
Winter cover crops are plants that can tolerate freezing temps. For us, that means about 15 degrees F. The mixture includes a blend of legumes including vetches, peas and bell beans. These are all “nitrogen fixing”, which means taking this important element from the air and putting it in the ground for the plant’s use. Oats and barley which are deeper-rooted act as a scaffold for the vining peas and vetch.
We do some summer cover cropping — sudan grass and buckwheat in particular as shown above, but because it needs to be irrigated we tend to plant most of the cover crops in the winter to take advantage of the free water.