It’s beginning to look a lot like… Fall. The weather is perfect, the soil still warm and the storm door is opening for those gentle autumn rains that do so much good for our gardens and the forest.
I stopped by Mountain Feed & Farm Supply in Ben Lomond recently to see what kinds of seed they had for erosion control and cover crops and believe you me they are fully stocked. The knowledgeable staff can help you decide which seed is best for your situation. They showed me about 20 different kinds of erosion control and cover crop seed as well as pasture and wildflower mixes, clovers and native seed mixes. One of their shop cats, who looks a lot like my Archer, is named Jan. How cool is that? Now’s the time to get that seed in the ground.
Often erosion control plants need to adapt to shallow, poor soil and cope with less than ideal conditions, all while putting down dense, strong roots. Native shrubs are great for long-term control but they can take a few seasons to get established. Mountain Feed carries mixes like Holdfast Native Blend and Grasslands Native Perennial Blend. Some of the seeds included in these mixes are California Brome, Wild Rye, California Poppy, Lupine, Barley, Ryegrass and Purple Needle Grass.
For those of you who raise chickens, there is a Chicken Pasture Mix with ryegrass, peas, oats, clover, flax, mustard and the legume Birdsfoot Trefoil. Horse owners might be interested in the Horse Dry Land Mix with perennial ryegrass, clover and orchard grass.
Planting a cover crop is another way to improve and retain your soil. Remember that every drop of rain that hits bare soil is destructive. Over 3,000 years ago the Chinese protected their soil from erosion and increased fertility by planting cover crops. Early Nile Valley inhabitants also practiced this method of agriculture as did first century Romans. Lupines were planted in poor soil when no animal manure was to be had.
Cover crops like bell beans, vetch and fava beans are especially valuable as they increase nitrogen levels in the soil in two ways. Atmospheric nitrogen can be “fixed” and left in the soil to fertilize subsequent crops. This is in addition to the nitrogen left from the foliage of the legume. Growing a cover crop also increases beneficial soil bacteria.
Cover crops are called green manure when they are chopped up and turned into the soil in spring before going to seed. The planting of legumes like peas and beans can actually increase nutrients in your soil giving you a net gain which is needed to offset what you take out of the soil when you harvest fruits, vegetables and flowers.
Now through the end of November is the best time to sow cover crops. You will need to irrigate lightly a couple times per week if it doesn’t rain. You can also wait to sow just before the rains start. Be careful about working overly wet soil, however, as you can ruin the structure of your soil.
Recent research now recommends planting a mixture of grasses and legumes. Annual cereal grasses such as oats, rye and barley germinated quickly to hold and shield the soil until the legumes take hold. Bell beans, fava beans and vetch, which are the best legumes for our area, grow slowly the first three months then take off growing 70-80% in the last three months. The ratio of grass seed to legumes can vary from 10% to 30%.
There are other legumes that fix nitrogen but nowhere near as efficiently as bell beans. Mustard causes competition with the fruit trees as bees will concentrate on the mustard flowers instead of the fruit tree flowers but is good in other situations. Mountain Feed carries a Bee-Friendly Cover Crop mix that includes several types of clover.
You don’t need to use inoculants on legume seed. Our soils have a native resident population of good bacteria that will break down the seed coat and encourage the plant roots to fix more nitrogen especially after cover cropping for a few years.
Work the soil lightly with a metal bow rake then broadcast 8-10 seeds per square foot. Weeds should be already cleared but this step doesn’t have to be perfect. Afterward the area should be raked again lightly 1-2 inches down and covered with 3-4 inches of straw. Wood chips would be fine, too. Mulch heavier if you have bird competition. Cover crops are vigorous and will come up through just about anything. Water in lightly.
If you plan to let your small vegetable garden lie fallow over the winter instead of planting it with a cover crop you can cover it with manure and straw.
Jan Nelson, a landscape designer and California-certified nursery professional, will answer questions about gardening in the Santa Cruz Mountains. Email her at ja******@ao*.com, or visit jannelsonlandscapedesign.com.
