Tag Archives: cover crops

Cover Crops Enrich Soil & Prevent Erosion

A mixture of grasses and legumes grown as a cover crop and tilled into the soil in spring increases soil fertility.

If you’ve been waiting to plant a cover crop , wait no more. The soil is now moist and still warm enough to germinate seed easily. Remember that every drop of rain that hits bare soil is destructive. Over 3000 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. Planting a cover crop is another way to improve and retain your soil.

A cover crop is really anything that covers the soil and protects it from rain, trapping nutrients and preventing them from leaching downward. Cover crops can increase the tilth of the soil. Quick germinating grasses easily loosen the top foot of soil with their root mass. Legumes have a tap root, a bio drill, that penetrates 30 inches downward while alfalfa roots can grow even deeper.

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 3 months then take off growing 70-80% in the last 3 months. The ratio of grass seed to legumes can vary from 10% to 30%.

Orin Martin of UCSC Chadwick Garden demonstrates the remarkable root structure of bell beans.

There are other legumes that fix nitrogen but nowhere near as efficiently as bell beans. Crimson clover seed is more expensive, needs lots of water to sprout and competes poorly with weeds. Mustard causes competition with the fruit trees as bees will concentrate on the mustard flowers instead of the fruit tree flowers.

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.

Enriching the Soil with Cover Crops

Every drop of rain that hits bare soil is destructive. Over 3000 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. Planting a cover crop is another way to improve and retain your soil. One of these days winter rains will come so be ready.

A cover crop is really anything that covers the soil and protects it from rain, trapping nutrients and preventing them from leaching downward. Cover crops can increase the tilth of the soil. Quick germinating grasses easily loosen the top foot of soil with their root mass. Legumes have a tap root, a bio drill, that penetrates 30″ downward while alfalfa roots can grow even deeper.

Orin Martin of UCSC’s Alan Chadwick Garden shows the extensive root system of bell beans.

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.

Fava beans, when grown as a cover crop and tilled into the soil in spring, increases soil fertility.

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.

Late September to 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 3 months then take off growing 70-80% in the last 3 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. Crimson clover seed is more expensive, needs lots of water to sprout and competes poorly with weeds. Mustard causes competition with the fruit trees as bees will concentrate on the mustard flowers instead of the fruit tree flowers.

You don’t need to use an inoculant 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 and I’ll talk about that in another column.

Why Plant Cover Crops?

Cover crop mix

Every drop of rain that hits bare soil is destructive. Over 3000 years ago the Chinese increased their soil’s fertility and protected it from erosion 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. Planting a cover crop is another way to improve and retain your soil.

A cover crop is really anything that covers the soil and protects it from rain, trapping nutrients and preventing them from leaching downward. Cover crops can increase the tilth of the soil. Quick germinating grasses easily loosen the top foot of soil with their root mass. Legumes have a tap root, a bio drill, that penetrates 30″ downward while alfalfa roots can grow even deeper.

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.

Late September to 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.

Orin Martin shows the extensive root system of bell beans

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 3 months then take off growing 70-80% in the last 3 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. Crimson clover seed is more expensive, needs lots of water to sprout and competes poorly with weeds. Mustard causes competition with the fruit trees as bees will concentrate on the mustard flowers instead of the fruit tree flowers.

You don’t need to use innoculants 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.

Planting Cover Crops to Enrich Your Soil

Every drop of rain that hits bare soil is destructive. Over 3000 years ago the Chinese knew how to protect their soil from erosion and increase 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. Planting a cover crop is another way to improve and retain your soil.

UCSC Farm & Garden cover crops

A cover crop is really anything that covers the soil and protects it from rain, trapping nutrients and preventing them from leaching downward. Cover crops can increase the tilth of the soil. Quick germinating grasses easily loosen the top foot of soil with their root mass. Legumes have a tap root, a bio drill, that penetrates 30″ downward while alfalfa roots can grow even deeper.

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 also 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.

Late September to 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.

fava beans

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 3 months then take off growing 70-80% in the last 3 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. Crimson clover seed is more expensive, needs lots of water to sprout and competes poorly with weeds. Mustard causes competition with the fruit trees as bees will concentrate on the mustard flowers instead of the fruit tree flowers.

You don’t need to use inoculates 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.

 

Late Summer Tasks for the Garden

It’s darker in the mornings now with the sunset coming earlier each evening. All that time I thought I’d have back in June to get things accomplished in the garden has vanished in what seems like a wink of an eye. Still the weather these days is perfect for being outside and pecking away at my to do list. There are also some late summer/early fall tasks that need attention.

alstroemeria_variegated
Alstroemeria ‘Rock & Roll’

Now through October, divide summer blooming perennials like alstroemeria, agapanthus, coreopsis, iris, daylily, yarrow, rudbeckia, calla lily, aster and penstemon that are overgrown and not flowering well. You can also divide spring blooming perennials like candytuft, columbine, astilbe, bergenia and bleeding heart although they don’t always bloom the first spring afterwards due to the energy they use re-establishing themselves. Start perennial flowers seeds now so that they will be mature enough to bloom next year.

This is the perfect time for transplanting or adding new plants to your garden. Why? Cooler air is kinder to plant foliage and soil temperatures are still warm which creates an excellent environment for new root growth. In the fall many plants and trees, even broadleaf evergreens, are entering a period of dormancy. With no need to allocate resources into foliage, plants are transferring all their energy into roots and storing nutrients for the cool months ahead. By spring, the new roots system should be well established.

Perhaps it’s time to remove or reduce lawn. Replant with more drought tolerant ornamental grasses or perennials.

achillea_pink
Achillea millefolium

Fertilize shrubs lightly one last time with an all-purpose organic fertilizer or layer of compost. This advice doesn’t apply to California natives. They like compost only around the roots during the winter while they get ready for their growing season.

Roses especially appreciate a bit of fertilizer now, encouraging them to bloom another round in the fall. To keep them blooming make a habit of pinching and pruning off old flowers. Always cut back to an outward facing branchlet with five leaves. There are hormones there that will cause a new flower bud to grow much sooner than if you cut to one with only three leaves.

Plant cool season veggie starts like broccoli, cabbage, cauliflower, chard, lettuce, spinach, brussels sprouts, onions and leeks in soil enriched with 4-6″ of compost as summer vegetable crops will have used up much of your soil’s nutrients.You can sow seeds of beets, carrots, radishes, spinach, arugula, mustard and peas directly in the ground.

soil_builder_cover_crop_mix-1600
Soil builder cover crop mix

If you aren’t going to grow vegetables in the garden this fall consider planting a cover crop like crimson clover, fava or bell beans after you’ve harvested your summer vegetables.

Cut back berries vines that have produced fruit. Canes of the current season should be trained in their place.

Spider mites are especially prolific during hot, dry weather. Sometimes you don’t even know how bad the infestation is until all your leaves are pale with stippling. Periodically rinse dust and dirt off leaves with water. Spray the undersides of infected leaves with organics like insecticidal soap switching to neem oil if they build up a resistance to one of the pesticides.

And whatever you do, enjoy being outside in this beautiful place we call home.

Growing Cover Crops – Part II

Orin_Martin_bell_beansOrin Martin of the Alan Chadwick Garden on the UCSC campus is widely admired for his incredible knowledge and skills as a master orchardist, horticulturalist and teacher. I was lucky a couple of years ago when he visited a group of fellow designers and brought his favorite russet apples. Another time he brought a dozen different kinds of potatoes that we roasted, critiqued and thoroughly enjoyed.

The Alan Chadwick Garden was nothing but poison oak and chaparral in 1967 when Alan Chadwick first got his hands on it. Martin came to UCSC in 1969 as a literature major but was soon impressed with Chadwick’s work, preaching the gospel of treating the garden as a self-nourishing system. Together they worked the garden, building the soil and teaching others.

Now Martin runs the appreaster_Michaelmas_daisy.2048ntice program which teaches future organic gardeners and shares his knowledge in workshops like the Cover Crop class I recently attended.

Last week I wrote about how and why to plant cover crops. This is what to do next spring after they’ve done their magic in the soil fixing nitrogen.

Cover crops are plowed or skimmed off in late February to early April. Because it takes 3-5 weeks for the cover crop to break down so crops can be seeded or transplanted, it is often best to skim off the cover crop at the base of the plants and combine with straw or leaves to make compost. Previously made compost can then be applied to the surface. It is important to retain the roots and nitrogen-filled nodules in the soil. Take only the vegetative portion.

cover_crops_Orin_Martin.1280Another method is to skim the foliage with a weed wacker or mower chopping it into small pieces 1/4″ to  4″ long. You can then rototill this into the soil and allow it to decompose on its own. In about 2 weeks the material should be broken down to be unrecognizable as plant material before replanting.

If you are developing your soil to build organic matter and improve structure incorporate the cover crop at a more mature stage (half to full bloom) when it has a higher carbon content. The nutrients will be stored in the reservoir of humus and released slowly over a number of years.

On established soils where you want primarily to fertilize next spring and summers crops, incorporate the cover crop after skimming and chopping when it has just started to flower as it decomposes quickly at this stage.

The Chadwick Garden fertilizes its established fruit trees by simply cutting down the cover crop growing at their base with a machete at the 25% flowering stage. 4-6″ of wood chips are laid over the chopped up pieces and left for nature to decompose. That’s all their is to it. Martin explained that the garden used blood meal and the organic fertilizer, Sustane, during the first several years while the trees were becoming established.

Picking up a clump of grass sown just 2 weeks ago, Martin teased off the soil to show the vigorous, fibrous root mass. “This is why the riches soils of the world, the Steppes of Russia and the original Midwest prairies, are so fertile and are called bread basket soils”, he explained.

Plant a cover crop this fall and your soil will be richer for it.