Plant care & info

Cover crops can provide a wonderful habitat for the pollinators that help keep your garden thriving. Flowering cover crops such as crimson clover, buckwheat, alfalfa, and mustard attract bees and beneficial insects that help with pollination and insect control in the garden. Cover crops encourage beneficial insects by providing flowers for a nectar source and foliage for shelter.

Large amounts of organic matter are added to the soil when the lush growth of green, mature crops is turned under. Organic matter improves soil texture as humus and stabilizes moisture content. The plant nutrients in these crops are returned to the soil, thus becoming a storehouse for nutrients.

Legume plants are hosts to nitrogen-fixing bacteria which extract nitrogen from the air and convert it into a form that can be used by plants. When used as a cover crop, legumes return the nitrogen to the soil.

Some cover crops, like oilseed radish and fava bean, are deeply rooted. Their taproot is excellent at breaking apart hard clay soils and providing much needed airspace. Cover crops planted in your garden will also serve as “living mulch” that helps to prevent erosion, nutrient loss from leaching, and weed growth.

Spring and summer cover crops are planted after the danger of hard frost has passed.

After your garden produce is harvested, till the plant residue into the soil where it will decompose to produce more humus. This also prepares the soil for the cover crop seed. You may use either a drop spreader, a broadcast spreader, or simply broadcast the seed by hand.

For more even coverage, make two seeding passes over the garden at right angles to each other. Lightly rake the seed into the top ¼ inch of soil. The seed must be covered and be in firm contact with the soil for best germination.

If you seed before fall rains begin, the seeded area should be watered lightly to keep it moist until the seeds germinate. Cover with compost for added benefit.

Most gardeners know about the benefits of adding organic matter to the soil. Many of us build the soil with annual applications of compost, manure, leaves, and grass clippings. Cover crops allow you to avoid importing soil amendments. By growing your own organic matter, you eliminate the fossil fuels needed to transport imported amendments, helping to make your yard a closed loop of energy inputs. (Ref: Edible Landscaping with Charlie Nardozzi: Fall Garden Cover Crops).

With cover crops, large amounts of organic matter are added to the soil when the lush growth of green, mature crops is turned under. Organic matter improves soil texture as humus and stabilizes moisture content. The plant nutrients in these crops are returned to the soil, thus becoming a storehouse for nutrients.

Portland Nursery carries a large selection of bulk cover crop seed for spring & summer planting.

EXPLORE COVER CROP OPTIONS

Annual Ryegrass

This annual, cool-season grass is adapted to late fall seeding. It germinates rapidly and is tolerant of hard, difficult soils. It has excellent root mass, continuing to grow at low temperatures and at lower pH ranges. When tilled into the soil in spring, it adds organic matter to improve the soil texture and workability. Plant in full sun/light shade.

Sow: September through November

Coverage: 1 lb. per 500 sq. ft.

Austrian Peas

Large-seeded legumes such as Austrian peas are very good for use as cover crops, building soil tilth and adding organic matter to the soil. Peas like well drained, fertile loamy soils. Highly recommended for previously worked soils. Plant in full sun.

Sow: Plant through December.

Coverage: 1 lb. per 200 sq. ft.

Buckwheat

A summer annual, buckwheat grows rapidly and begins to flower in as little as 5 to 6 weeks after germination. It should be tilled into the soil or cut and composted when it begins to flower. A densely growing stand of buckwheat helps shade out weeds. It is adapted to soils that are slightly acidic.

Sow: May through late October

Coverage: 1 lb. per 400 sq. ft.

Common Vetch

Less winter hardy than hairy vetch, common vetch is best adapted to well drained, fertile soils. It is not tolerant of wet soils. Vetches are annual, vine-type legumes with leaves ending in tendrils. An excellent nitrogen source and great for erosion control. Plant in full sun.

Sow: Mid- September to November

Coverage: 1 lb. per 400 sq. ft.

Crimson Clover

Tolerant of full sun or half shade, it will grow readily on both sandy and clay type soils, though it will not grow well with poor drainage. It forms a dense green carpet by mid-winter, and matures in April. The tender vegetation is easily tilled into the soil, adding organic matter. This annual captures free nitrogen from the air and converts it to a form available to other plants.

Sow: September to mid-October

Coverage: 1 lb. per 400 sq. ft.

Dutch White Clover

A long-lived legume adapted to silty loam and clay soils with pH range of 6.0 to 7.0. The roots seldom grow deeper than 2 feet. It reaches a mature height of 4-8”. Plant in full sun to half shade.

Sow: July through November

Coverage: 1lb per 2000 sq. ft.

Fall Cereal Rye

Fall rye germinates quickly and grows rapidly in cool weather, making it an ideal cover crop. It is one of the earliest and hardiest of the cereal grains. It tolerates heavy soils, low pH, and poor drainage. When grown as a cover crop, it may be seeded as early as August. Plant in full sun to light shade.

Sow: August through December

Coverage: 1 lb. per 250 sq. ft.

Oil Seed Radish

This deep-rooted cover crop is best used in hard, previously unused soil. The taproot is excellent at breaking apart hard soil and provides much needed airspace. Winter temperatures kill off the plant, and the taproot slowly decomposes for easy tillage in the spring. Fast growing it provides quick erosion control.

Sow: September through October.

Coverage: 1 lb. per 2000-3000 sq. ft.

Fava Bean

Fava bean is not really a bean, but a member of the pea family. This tall legume is vigorous, deep rooted, and an excellent nitrogen fixer. The deep taproot loosens hard soils. It is best planted in full sun and tolerates most soil types.

Sow: Mid to late October

Coverage: 1 lb. per 350 sq. ft.

Gardenway Mixture

The Gardenway Mixture is 35% HyOctane triticale, 28% Austrian field pea, 25% Walken oat, 9% common vetch, 2% annual rye, and 1% crimson clover.

The gardener who selects this cover crop mix receives many advantages. Large amounts of organic matter from roots and leaves, when tilled under in the spring, result in improved soil tilth. Crimson clover may return enough nitrogen that many crops may be grown without additional fertilizers. These crops provide competition to inhibit weed growth. Nutrient loss from leaching is reduced.

Sow: Early spring or fall, depending on goals

Coverage: 1 lb. per 250 sq. ft.