Why would you want a cover crop?
- It can be a great green manure that can be dug back into the soil
- Great as a nitrogen fixing plant, storing nitrogen from the air into nodules on the roots
- A natural way to provide weed protection
- Can help stop the effects of soil erosion caused by wind, rain and the sun.
- Water retention can be improved in soils with hard soil pans
- Can control soil borne fungi and nematode problems within the soil
What type of cover crops are there?
There are a lot you can pick from and they can all offer different benefits to the soil, keeping an eye on when you can actually plant it may limit you to certain types.
All the cover crops below can be purchased from Kings Seeds in small inexpensive qty’s
Blue Lupin (Lupinus agustifolius)
Benefits – Excellent green manure for improving most soil types in most areas.
Growth – Vigorous grower that produces a mass of green matter and also nodules of nitrogen on it’s roots.
What to do – Breaks down quickly when chopped prior to flowering and dug into the soil
Sow rate – 250g to 300g per 50 m2 or 25kg per acre anytime between spring and autumn.
Buckwheat (Fagopyrum esculentum)
Benefits – Fast growth easy to till. Excellent beneficial insect crop.
Growth – Frost sensitive and prefers warm soils.
What to do – Till or hoe in at any stage.
Sow Rate – Late spring and summer at a rate of 250g per 10m2 or 2.5kg per 100 m2.
Crimson Clover (Trifolium incarnatum)
Benefits – Multipurpose nitrogen fixing legume and beneficial insect plant.
Growth – Sow late summer for rapid bulky upright growth. It goes dormant in the cold of winter before resuming growth in spring up to 1m high and sporting a striking crimson bloom in early summer.
What to do – Chop and dig in prior to flowering or leave for a valuable nectar rich food supply for bees and beneficial insects.
Sow rate – 250g per 100m2 or 10kg per acre (30% less if blended with a grain or grass).
Kings green manure mix (Various)
Benefits – Ready made mix for green manure, breaking up soil pans and nitrogen fixing.Contains 60% Peas, 20% Oats and 20% Lupin.
Growth – Best for spring sowing but suitable for sowing right through to late summer.
What to do – Mid and late summer sowings may be left to winter over and ploughed in during spring to suit your garden schedule.
Sow rate – 1kg per 40m2 or 100kg per acre and cover seed lightly.
Lucerne (Medicago sativa)
Benefits – Establishes easily and perfect for rejuvenating worn out soil. Breaks up soil pans with its vigorous root growth and draws up sub-surface minerals.
Growth – Drought resistant.
What to do – Cut for a nitrogen rich mulch or plough in as a green manure.
Sow rate – Sow in spring at a rate of 100g per 40m2 or 10kg per acre. Use half this rate when mixed with grain
Marigold (Tagetes patula)
Benefits – Grown as a rotation crop for nematode control especially with or after tomatoes and in kiwifruit orchards around the vine root zones. The marigold root exudes ozone which encourages all nematodes in the root zone to mature without reproducing.
Growth – Grows 30-40cm tall.
What to do – Chop or plough in prior to flowering.
Sow rate – Sow after last frost onwards at a rate of 1g per 2m2 or plant out at 10-20 seedlings per m2.
Mixed grain carbon crop (Wheat, Oats, Barley)
Benefits – Very effective spring planted cover crop or can be sown late summer to provide stubble and seed for wildlife and to prevent soil erosion.
Growth – Provides lots of organic matter when ploughed in green.
What to do – Dig or plough in anytime.
Sow rates – Sow at a rate of 1kg per 150m2. 1kg
Mustard (Brassica alba)
Benefits – Excellent for weed seed control and cleaning up some harmful soil fungi.
Growth – Very fast growing and prefers moist soil.
What to do – Dig or plough in after 4-6 weeks and prior to flowering.
Sow rates – Sow from September through to April (cover seed slightly with soil) at a rate of 100g per 35m2.
Phacelia (Phacelia tanacetifolia)
Benefits – Quick growing manure crop or as a sanctuary for predator insects to feed and plan their assaults from.
Growth – Quick growing
What to do – Dig or plough in anytime.
Sow rates – Sow from September through to April at a rate of 30g per 10m2 or 1kg per 300m2.
Broad beans (Vicia faba)
Benefits – Fixes nitrogen on its roots, inhibits fusarium wilt and provides ample humus when dug in.
What to do – Chop and dig prior to flowering.
Sow rates – Sow 1kg seed per 50 square metres.
Soybean (Glycine max)
Benefits – Excellent green manure crop and nutritious livestock feed crop.
Growth – Soy grows rapidly to bushy 1m tall plants and will compete with weeds. Will fix approx 60kg nitrogen per acre in the soil and is high in organic matter.
What to do – Mulch prior to seed set.
Sow rates – Sow late spring/early summer once the ground has warmed to 18 degrees C and last frosts have passed. Sow 1kg per 60 square metres or 70kg per acre.
Have you used cover crops?
Let me know in the comments below what has worked well for you.