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and Green Manure Crops for the Home Garden
[Source: RCE Fact Sheet "Cover Crops and Green Manure Crops: Benefits, Selection and Use" by Daniel Kluchinski, Mercer County Agricultural Agent]
Editors Note: This Fact Sheet is oriented toward large scale flowers, but the information is also relevant to home gardens.
crop is a crop grown to protect the soil from erosion.
A green manure is a crop which is plowed under for soil improvement.
If a cover crop is plowed into the soil, it becomes a green manure. Cover and green manure crops were used extensively before the development of synthetic fertilizers and pesticides. Recent interest in sustainable agriculture have farmers reconsidering the use of these crops. Both cover and green manure crops provide benefits that may increase consideration for their use. They can:
In New Jersey, traditional cover crops include small grains such as rye or wheat. Hairy vetch, clovers and other grasses and legumes are gaining popularity. However, selecting and integrating cover and green manure crops into a production system should entail evaluation of your own production system and the characteristics of the individual species.
In selecting a cover crop, first identify your objective, problem or need. Determine what would be the ideal species that would fit your needs, then match this with the best available cover/green manure crop.
Cover and green manure crops can be grown at different times of the year. Depending on the crop rotation being used, they can be grown after a cash crop or over-seeded (planted into a standing crop). They can protect the soil over winter, then be plowed into the soil. It is important to identify the time period that the cover or green manure crop can be successfully established. Then, one must consider how the crop will be planted. To begin, consider the following:
By combining the selection and integration process when planning, a list of needs or requirements can be drawn up. Understand that it may be difficult to determine what species might be best suited, as individual production practices and conditions will vary greatly for every farmer.
Before planting one species on a large scale, evaluate the choices that appear to be best suited for your needs. Use test strips within your field. One method is to select areas that are 10 x 50 feet or larger. Plant at least 2 species or several varieties of one species. Record date and rate of seeding and subsequent weather conditions, particularly those affecting emergence and establishment of seedlings. Also note vigor, competitiveness and ease of control. then select the best species for your situation, considering cost, availability of seed, ease of establishment, degree of erosion control, weed control, or benefit to the following cash crop.
Cover or green manure crops can be very beneficial when the correct crop is selected and properly used. When selecting a cover or green manure species, first identify your objectives or needs and the time period when the cover crop can be successfully established. Then consider which would best fit you situation and match it with the best available species. To determine the best fit for your conditions, test several species within your field, then choose the best based on performance, cost and availability.
Best choices for planning now and
seeding rate for 1000 sq. feet:
Winter Barley=2 - 3 lbs.
Rye (Grain)=2 - 2.5 lbs.
Winter Wheat=2 - 3 lbs.
Considerations include seed availability, cost and ease of management.
Buckwheat is a broadleaf summer annual with no winter hardiness. It is moderately shade tolerant and a fast grower that germinates well in dry soil. It is a great 'smother' crop used to shade and out compete weeds. Seed in late spring for use as a summer cover at 3/4 to 3 lb./1000 sq. ft.
Alsike clover, a legume as are all clovers, is a biennial or perennial with good winter hardiness. It is moderately shade tolerant and is the best clover for wet sites and acidic soils. It can be undersown into the vegetable garden under plants like tomatoes, peppers or sweet corn, where it will germinate and then grow after these primary crops are removed. Seed in spring or late summer at 1 and 1/2 to 2 and 1/2 oz./1000 sq. ft.
Crimson clover is a perennial with moderate winter hardiness and high shade tolerance. It is a fast grower. Seed in spring or late summer at 1/3 to 1/2 lb./1000 sq. ft.
Red cover is a short lived perennial with good winter hardiness and high shade tolerance. Its taproot can help break up compacted soil. Seed in spring or late summer at 1/4 lb./1000 sq. ft.
Annual white sweet clover is an annual with no winter hardiness and high shade tolerance. It requires soil pH over 6.0, is a fast grower and makes a good summer cover crop. Seed in spring only at 6 to 12 oz./1000 sq. ft.
Biennial sweet clover is a biennial with good winter hardiness, moderate shade tolerance, and requires soil pH over 6.0. The taproot helps break up compacted soil. Seed in spring or late summer at 3 to 6 oz./1000 sq. ft.
Oats, a small grain, is an annual with no winter hardiness and moderate shade tolerance. It is a fast grower that is used for fall cover or green manure. Seed in late summer for fall cover (the winter killed debris provides some cover through winter) or in spring for green manure. Seed at 1 and 1/2 to 2 and 1/4 lb./1000 sq. ft.
Winter rye, a small grain, is a winter annual with excellent winter hardiness and high shade tolerance. It germinates and grows quickly, tolerates wet, dry, low fertility and low pH soil conditions. Seed in early to late fall at 2 to 2 and 1/2 lb./1000 sq. ft.
Hairy vetch, a legume, is a winter annual with moderate winter hardiness and shade tolerance. It makes most of its growth in spring and must be tilled (or killed) before seed matures. If left to self-seed, you will 'enjoy' this cover crop for years. It can be sown with rye. Seed in early fall at 1/2 to 1 lb./1000 sq. ft.
Winter wheat, a small grain, is a winter annual with good winter hardiness that is easy to establish. Seed in mid-fall at 2 to 3 lb./1000 sq. ft.
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