Alsike Clover
Trifolium hybridum. Alsike grows where many other clovers will not. It tolerates heavy clay soil, and even areas prone to flooding. It is a weak-stemmed plant that uses neighbouring grasses to keep it upright to a height of around 40cm (16”), though it can grow a little taller in high grasses.
Timing: Alsike clover does best from spring or fall sowing. Sow late winter to mid spring, or August to early October.
Seeding: Sow seeds 5mm (¼") deep.
Cropping: Alsike can also be mowed back fairly hard when needed. It is best suited to cool summer growing in full sun. Alsike can fix 60-120 lbs of Nitrogen per acre per year. It is hardy to Zone 3. If grown for hay, it should be kept to less than 5% of the total mass.
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Alyssum
Lobularia maritima. The fast growth of this annual helps to smother weeds. At the same time, its tiny flower clusters attract beneficial predatory insects that will combat pest species throughout summer. The purpose of this cover crop is not to build soil as much as to generally benefit the garden.
Timing: Sow Alyssum from April to late June, and again in late August and early September. Hardy to Zone 3: -40°C (-40°F).
Seeding: Sow seeds on the soil surface, as they require light to germinate.
Cropping: Alyssum can be tilled under or cut and composted at the end of the season.
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Annual Ryegrass
Lolium multiflorum. Hardy annual. The deep roots of this crop penetrate even hard packed soil to introduce oxygen and water pathways that can be used by other plants when it dies back at frost. Its foliage loads up with carbon and nitrogen, which is then released to the crops that follow.
Timing: In Zone 6 or warmer, it makes an excellent fall cover crop, and will hold soil in place over winter. In Zone 5 or cooler, it’s better to sow mid-summer to early fall for spring tilling.
Seeding: Sow seeds 2-4cm (1-1½") deep.
Cropping: After its burst of spring growth, turn ryegrass under or cut it back before it reaches 30cm (12") tall. Allow three weeks after tilling before planting the next crop.
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Barley
Hordeum vulgare. Barley is a fast-growing annual with fibrous roots that can reach 2m (6') deep. It's excellent for erosion control, and it will hold nitrogen and carbon that will be released as it decomposes.
Timing: Sow barley any time during the growing season, from early March to the end of August. Barley does not overwinter in cold climates – it will winterkill at -8°C (17°F). To harvest grain, plant in the spring only.
Seeding: Sow to a depth of 2-4cm (1-1½").
Cropping: Cut or scythe and leave in place on the soil as a mulch. It can easily be worked into the soil with a garden fork. Allow two weeks before planting the
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Bees in Clover
This is a blend of four certified organic clover varieties Ladino, Medium Red, Alsike, and Crimson with Annual Ryegrass included as a nurse crop that will protect the seeds and soil until the clovers emerge. On quiet days the drove of bees buzzing from bloom to bloom will dazzle and delight.
Timing: Plant any time between late March and early October. Hardy to Zone 6: -23°C (-10°F).
Seeding: Sow seeds no deeper than 5mm (¼").
Cropping: The plants can be worked into the soil easily with a garden fork. For nitrogen fixation, allow the plants to grow and flower. After flowering, simply mow to allow the blend to re-flower.
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Buckwheat
Fagopyrum esculentum. Buckwheat grows very quickly and is one of the easiest soil builders to use. Its blooms will feed a host of pollinators, and then its brittle, succulent foliage can be turned under to improve soil texture and health.
Timing: Sow from the beginning of March through the end of August. Frost will kill this half-hardy annual.
Seeding: Sow seeds 2-4cm (1-1½") deep.
Cropping: Within ten days of blooming (or at any time before), buckwheat can be cut and turned under to improve soil tilth and add organic matter. The plants can be worked into the soil easily with a garden fork. The succulent plant matter decomposes quickly. Wait two weeks to plant the following crop.
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Chickpeas
Cicer arietinum. Sown densely, chickpea plants provide good coverage to protect soil from erosion. Allow the plants to grow to the flowering stage in order to benefit from the nitrogen fixation. Once the plants are cut, leave them in place as a nitrate-rich mulch.
Timing: Sow Chickpeas as a cover crop late winter to early summer. Do not soak the seeds prior to planting. Hardy to Zone 4: -34°C (-30°F).
Seeding: Apply seed inoculant to seeds before planting (optional). Sow seeds 5mm (¼") deep.
Cropping: For nitrogen fixation, allow plants to reach the flowering stage. We recommend cutting the abundant vegetation and leaving it on the soil as a mulch against weeds, to retain moisture, and provide insect habitat. Otherwise, work the bushy plants and their roots into the soil with a garden fork.
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Crimson Clover
Trifolium incarnatum. Within ten days of blooming (or at any time before), Crimson clover produces ample organic matter that can be used as a mulch on the surface, or cut and tilled under to improve soil tilth and promote soil health.
Timing: Plant any time between late March and early October. Hardy to Zone 6: -23°C (-10°F).
Seeding: Sow seeds no deeper than 5mm (¼").
Cropping: The plants can be worked into the soil easily with a garden fork. For nitrogen fixation, allow the plants to grow until flowering begins, and simply remove the tops and compost, leaving the roots intact in the soil. Allow ten days before planting the next crop, and avoid following with legumes like peas, beans, or soy.
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Fall Rye
Secale cereale. Rye improves soil tilth and drainage, prevents erosion, and suppresses weeds. Once tilled under, it is a good source of carbon-rich organic matter.
Timing: Plant fall rye in mid September for best results. The seeds will germinate as late as early November. A spring crop can be planted March through April. Hardy to Zone 3: -40°C (-40°F).
Seeding: Sow seeds 2-4cm (1-1½") deep.
Cropping: After its burst of spring growth, turn rye under or cut it back before it reaches 30cm (12") tall. Allow three weeks after tilling before planting the next crop.
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Fava Beans
Vicia faba. Small-seeded fava produces a taller plant than the broad beans grown for eating, resulting in abundant green manure. The plants stay brittle until seed sets, and can easily be scythed down or plowed under, even at 1.2m (5') tall.
Timing: Fava beans can be started as early as the end of January, or as late as early November. Plants grow slowly, and are hardy down to Zone 7: -17°C (0°F).
Seeding: Aim for a minimum of four plants per square foot. Sow seeds 5mm (¼") deep.
Cropping: For nitrogen fixation, allow the plants to grow until flowering begins. Cut plants at the surface and leave on the soil as a mulch, or use for compost. The large brittle plants can also be worked into the soil easily with a garden fork. Allow two weeks before planting the next crop.
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Hairy Vetch
Vicia villosa. The roots of this hardy annual extend deeply into the soil, improving porosity and drainage, and fixing nitrogen as they grow. The tops are lanky and sprawling, and can be cut in spring to provide an excellent mulch.
Timing: Sow Hairy Vetch from early March to mid-April, and again August to mid-September. Hardy to Zone 4: -34°C (-30°F).
Seeding: Apply seed inoculant to seeds before planting (optional). Sow seeds 5-10mm (¼-½") deep.
Cropping: For nitrogen fixation, allow plants to reach the flowering stage. We recommend cutting the abundant vegetation and leaving it on the soil as a mulch against weeds, to retain moisture, and provide insect habitat. Otherwise, work the long vines and their roots into the soil with a garden fork.
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Ladino Clover
Trifolium repens. Use Klondike Ladino clover as a nitrogen fixing cover crop, or as a long term ground cover, either on its own, or in combination with grasses. It tolerates wet conditions and foot traffic. It reduces soil compaction and improves soil health.
Timing: Ladino clover does best from spring or fall sowing. Sow March to May, or August to early October. This perennial is hardy to Zone 4: -34°C (-29°F).
Seeding: Sow seeds 5mm (¼") deep.
Cropping: For nitrogen fixation, allow the plants to reach flowering stage. Clover spreads by underground runners that call for more thorough tillage in the spring. A simple garden fork works well for this purpose. Allow two weeks for this clover to break down in the soil before planting the next crop.
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Medium Red Clover
Trifolium pratense. Perennial. We love red clover as a cover crop. Its thick, deep roots access nutrients lower in the soil column than many plants can reach and bring them to the surface. It can stand up to foot traffic, and can be mowed two to three times in summer, extending its bloom period.
Timing: Medium Red clover does best from spring or fall sowing. Sow after last frost, or August to early October.
Seeding: Sow seeds 5mm (¼") deep.
Cropping: Each time it is cut, it adds biomass to the soil, but we recommend that it be left in place to degrade back into the soil - or used as the green layer in composting. This clover is a short lived perennial that is hardy to Zone 4.
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Oats
Avena sativa. Oats are not particularly cold hardy, so a summer planted crop will die back, holding the soil in place, and providing ample carbon-rich organic matter to till under before planting spring vegetables.
Timing: The fast growth of this soil builder makes it ideal for sowing in the spring for erosion control or quick tilling. Planted in August, oats will put on a lot of growth and, in most winters, will be killed by frost. Hardy to Zone 8: -12°C (-10°F).
Seeding: Sow to a depth of 2-4cm (1-1½").
Cropping: Oats are less weedy and tenacious than fall rye, and are easily worked into the soil with a garden fork. Allow two weeks before planting the next crop.
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Perennial Ryegrass
Lolium perenne. Perrenial. This is one of the fastest growing grasses of all, growing from seed to mowable lawn in just 21 days. It’s a very tough, hardy grass that forms clumps, rather than spreading by rhizomes, and it regenerates easily from wear.
Timing: Sow Perennial Ryegrass nearly any time between frost dates. It is ready for grazing within 60 days of planting. It is tolerant to heat, drought, and cold, and has natural resistance to diseases that can hamper other species.
Seeding: Sow seeds 2-4cm (1-1½") deep.
Cropping: After its burst of spring growth, turn ryegrass under or cut it back before it reaches 30cm (12") tall. Allow three weeks after tilling before planting the next crop.
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Spring Field Peas
Pisum sativum. This fast-growing annual produces ample organic matter that can be used as a mulch on the surface, or tilled under to improve soil texture and promote soil health.
Timing: Sow mid February to May and again from late August to the beginning of October. This pea is hardy to Zone 6: -23°C (-10°F).
Seeding: Sow to a depth of 2-6cm (1-2½").
Cropping: For nitrogen fixation, allow plants to reach the flowering stage. If tilling under, allow two weeks before planting the next crop. Avoid following this cover crop with other legumes, like peas, beans, or soy.
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Triticale
Triticale hexaploide. When rye pollen is used to pollinate wheat flowers, the result is the remarkable hybrid known as triticale. It has a similar, albeit weaker, allelopathic effect to Fall Rye, but without the dense root system. Its grains are more nutritious than wheat, with less glutenin. As a grass it is considered awnless, which makes it an excellent forage for livestock. Triticale is nearly as hardy as Winter Wheat, with even better disease resistance.
Timing: Sow in the fall, as the vernalization triggers seed production. Spring and summer sown Triticale will not produce seeds.
Seeding: Prepare the seed bed the same as for oats, wheat, or barley. Triticale can be grown for use as wheatgrass.
Cropping: After its burst of spring growth, turn triticale under or cut it back before it reaches 30cm (12") tall. Allow 3 weeks after tilling before planting the next crop.
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White Dutch Clover
Trifolium repens. Use White Dutch clover as a nitrogen fixing cover crop, or as a long term ground cover, either on its own, or in combination with grasses. It tolerates wet conditions and foot traffic. It reduces soil compaction and improves soil health.
Timing: White Dutch clover does best from spring or fall sowing. Sow March to May, or August to early October. This perennial is hardy to Zone 4: -34°C (-29°F).
Seeding: Sow seeds 5mm (¼") deep.
Cropping: For nitrogen fixation, allow the plants to reach flowering stage. Clover spreads by underground runners that call for more thorough tillage in the spring. A simple garden fork works well for this purpose. Allow two weeks for this clover to break down in the soil before planting the next crop.
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White Mustard
Sinapis alba. Allow this fast growing annual to grow early in the season, and then till it under as an effective fumigant against Verticillium, common root rot, and soil nematodes.
Timing: Sow this mustard in early spring, from the first of March to mid-May. It can also be planted mid-August to mid-October. Hardy to Zone 8: It will winterkill at -3°C (26°F).
Seeding: Sow to a depth of 5-10mm (¼-½").
Cropping: Seeds should sprout in 3-5 days. Integrate the plant matter into the soil once plants are 90-150cm (36-60") tall. Otherwise, cut the plants and leave them as a mulch on the soil surface. Allow three weeks before planting the next crop, and avoid following with Brassicas.
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Winter Field Peas
Pisum sativum. This fast-growing annual produces ample organic matter that can be used as a mulch on the surface, or tilled under to improve soil texture and promote soil health.
Timing: Sow mid February to May and again from late August to the beginning of October. This pea is hardy to Zone 6: -23°C (-10°F).
Seeding: Sow to a depth of 2-6cm (1-2½").
Cropping: For nitrogen fixation, allow plants to reach the flowering stage. If tilling under, allow two weeks before planting the next crop. Avoid following this cover crop with other legumes, like peas, beans, or soy.
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Winter Wheat
Triticum sp. The benefit of winter wheat is its hardiness. It all but eliminates winter soil erosion, and then supplies a source of carbon-rich organic matter to till under before planting vegetable crops.
Timing: Sow in September. Winter wheat is hardy to Zone 3: -40°C (-40°F). Unlike oats, this cold-hardy cereal will not die off over winter.
Seeding: Sow to a depth of 2cm (1").
Cropping: The germinated seeds lie dormant in frosty soil, and then burst into growth in the spring, providing a greater nitrogen to carbon ratio when it is tilled
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Yellow Sweet Clover
Melilotus officinalis. Biennial. This relative of clover improves soil structure, fixes nitrogen, provides nutritious pasturage, and feeds honey bees. Its widely branched taproots penetrate the subsoil deeply, using nutrients unavailable to other plants.
Timing: Yellow Sweet clover does best from spring or fall sowing. Sow March to May, or August to early October. This perennial is hardy to Zone 4: -34°C (-29°F).
Seeding: Sow seeds 5mm (¼") deep.
Cropping: Plants will reach 30-90cm (12-36”) tall in the first year of growth. In year two growth (including flower stalks) starts from the base. At full maturity, they can reach 1.2–1.8m (4-6’) tall. We recommend tilling under when the second year growth reaches 15cm (6”).