Cover Crop


There are many reasons for organic farmers, gardeners, vineyard, and orchard growers to use cover crops over the winter months. The benefits are numerous!

-As the local area around Sebastopol has typically heavy-clay soil, with low amounts of organic matter, N, P, K, CA, Su and other micronutrients, cover cropping is an ideal organic approach to adding all of these crucial components back into the our soil. Along with reliable compost, relatively low-cost ‘cover-cropping’ reduces or eliminates the need for more expensive and toxic (or potentially-‘hot’) amendments such as non-organic (i.e. conventional/chemical) fertilizers.

-Legumes (e.g. beans, peas, vetch and covers) have roots that ‘fix’ (add) nitrogen (N) into the soil.

Legumes as cover crops can be mowed (or scythed) and tilled into the soil in the spring (before planting of spring crops), which will add ample organic matter back into the soil. “Tilling under” of legumes should be done before flowers mature into viable seeds (while N remains within the softer foliar matter).

-Also there’s no need to irrigate (unless using perennial clovers) as we let the rain do the work!

                  Rich in varying ratios of legumes, the ‘Organic Matter Mazimizer’, ‘Organic Matter Builder’, and ’Green Manure’ Mixes are all popular for the above reasons. Inoculant (in small white bags) can be added to legume seeds just prior to planning to increase rhizobial activity in soil, increase N-fixing properties, and help the legumes’ uptake of vital nutrients from the soil.

Annual clovers (aka ‘Subclovers’) for a dense low and spreading mat of nutrient-rich foliage, which when allowed to mature will form dormant seed pods, which dry in the summer months and re-seed themselves in the next autumn rains. Where/when irrigation is not provided after the rains cease, and when re-seeding is not desired, annual clovers should be used, to be tilled under to build organic matter, increase nitrogen and overall soil health.

Perennial clovers (live Rose or Crimson) are often used in vineyard rows where tillage is not desired or required, but where irrigation will be provided after the rains have ceased (around Mar-June). Clover blooms will offer excellent forage for beneficial and pollinating insects, butterflies and honeybees!

*PLEASE NOTE: Clovers and Legumes will not release N-fixing nodules from roots if existing soil is low in Phosphorus! [When nodule’s inside is pink there is N-fixing occurring (good!) When nodule’s inside is white or grey, no N-fixing (not so good!)] To compensate for low ‘P’ in soil composition, apply adequate rate of (organic) Soft Rock Phosphate (SRP50).

Barley, Red Oats, and Cereal Rye can be used to help provide erosion control on sloped land, and for adding more Carbon and organic matter as well. The more variety of cover crops used the better!

Yellow Mustard is grown prolifically in the Napa and Sonoma County winemaking vineyard regions. It is a permanent cover crop with a strong deep taproot which helps to break down poorer, clay soils, and adds a good deal of Nitrogen. ‘YM’ is also a member of the Brassica family, which has been shown be beneficial in preventing harmful nematodes when tilled under in vineyard rows. Negatively, YM may attract lacewings and other pest insects in areas close to streams, riparian zones…

                  Waning: DO NOT USE Annual Rye Grass in any area that is being prepared for growing spring crops i.e. as a cover crop. When tilled under or mowed, ‘ARG’ does not decompose into beneficial organic matter, but contains toxins, which damage microbial and overall soil health. For these reasons, only use ‘ARG’ for erosion control and/or early winter weed eradication measures in pasture of meadow areas where crops are not going to be grown!

Harmony Farm Supply offers all the above Cover Crops seeds in bulk, with standard discounts offered with quantities of each seed item over 50 lbs. Additionally, HFS offers many Wildflower blends  (also in bulk, and ¼ lb bags) as well as two Beneficial Insect Blends which help attract beneficial and predatory insects to farms and vineyards. (Especially helpful in preventing lacewings and resultant ‘Piece’s Disease’). Remember, when you see ladybugs, butterflies, honeybees, spiders and/or earthworms, you most likely have a health garden, farm, or vineyard!

Fall 2023 Cover Crop Catalog

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