Grow a Cover Crop-How to

Written By GoodEarth GardenSchool

Author Ellen Vande Visse

Cover crop maturing:

Fava, oats, pea

It will winter-kill, will not come back in the spring

or Green Manure

A Blend of Seed Now Available for Alaska Soils

You’ve heard me preach—build your soil fertility with cover crops. Renew your
worn-out soil after last year’s growing season. This is the heart of organic growing.

But there are always the questions…

  1. which cover crop for Alaska?

  2. when do I plant it?

  3. will it become invasive?

  4. shipping expenses?

You see, I recommend a cocktail of cover crops, not just a single one like rye grass. I asked AK Mill & Feed about carrying a special blend for cold climate conditions. The answer—YES!

So, I provided the formula, and AK Mill has blended and packaged it. Hurrah! It’s available now.

…Announcing…
Alaska Soil Booster

A Green Manure/Cover Crop — Custom Blended by Alaska Mill & Feed. Sold in 6lb jugs, 20lb bags, 40lb bags, or custom large quantities

Purpose: this cover crop is specially formulated for Alaska farmers and gardeners as a green manure. Green manure refers to turning the cover crop back under the soil when it’s still young and tender. You will:

  1. feed microbes

  2. build organic matter

  3. concentrate nutrients in the upper soil layer.


FOR A GREEN MANURE: You don’t let the crop get tall, mature, get tough, or make seed heads. When your crop is 4-6” high, you chop and turn it under/cultivate it using a rototiller, broad fork, or garden fork.

You can repeat this cycle up to 3 times per summer. Replant and plow down at least twice more during the growing season. Instead of chopping and plowing the 3rd round, leave it standing for the winter. It will serve to minimize wind & rain erosion. This crop will die or “winter-kill”, so it will not interfere next spring’s planting. This die-back crop will still store nitrogen and organic matter that will enrich the soil next spring.

Alaska Soil Booster, sold in 6lb jugs, 20lb bags, 40lb bags:

  1. Contains fava, oats, and Austrian pea seed.

  2. Produces organic matter plus nitrogen (pounds of it!)

  3. Feeds and maintains high populations of beneficial soil microbes

  4. Performs well in cool soils

  5. Includes nothing invasive

  6. Suppresses weeds

  7. Winter-kills. It dies over the winter (so you don’t fight a living mat next growing season)

  8. Excellent for green manuring: sow, grow, chop, cultivate, and sow again.

Alaska Soil Booster revitalizes worn out soil, and builds new luscious soil. Grow it right in place. Save your back. You can skip hauling compost & manure.

The Process:
–Sow (with inoculant)
–Grow
–Cut while young –turn under
–Repeat the above with 2 more sowings this same growing season

PRESTO! You have renewed & enriched your soil with home-grown nitrogen, superb texture, and an improved soil food web!

Put this section back into production next spring with no composting, & minimal need to fertilize.

The Timing: Five Strategies

1. Before you plant a main crop and/or after

  1. Delay your intended crop by 4-6 weeks while you green-manure the area. Or sow the cover crop first thing. Then crush and plant seeds of your crops into the mat.

  2. Follow your crops in the fall with a cover crop.

2. Under-sow an existing crop: interplant a living mulch amongst crops.

  1. Plant leaf lettuce under pea vines to shade soil & suppress weeds.

  2. Grow short-lived cover crop seed alongside your half-matured romaine lettuce or pak choi. When you harvest the crop, turn under the cover crop too.

3. Spot treatment

  1. Fill empty spaces as you harvest (e.g. cabbage, cauliflower) with cover crop seed.

4. New or resting plots

  1. Prepare a new field, or resting plot, or high tunnel area with a season’s worth of cover cropping or green manuring before cultivating a market crop.

5. Do one section of the garden per year

  1. Take 1/10th or 1/4th (for example) of your garden out of production for Year 1 and grow 3 successive green manure crops in this section. Rotate to next section for Year 2, while putting the first section back into production. Ask Ellen for a PDF of cover crop instructions.

Application rates for Alaska Soil Booster
– 1.5 lb for 100 sq. feet
– 3 to 5 lb for 1000 sq. feet
– 70 to 120 lb per acre. Bulk purchase—call for estimate 907-222-2047 at the Alaska Mill & Feed commercial & wholesale desk.
Sowing depth: 3/4” to 1” deep.
Apply with the proper inoculant (see below) for this blend’s legume components.

Benefits of this seed blend

  1. will not re-grow in the spring- it winter-kills

  2. you’ll grow miles of roots

  3. suppress weeds

  4. build microbe & worm populations

  5. store soil nutrients, minimize wind & water erosion

  6. improve tilth

  7. draw up subsoil minerals, & accumulate them in the topsoil

Do the math — A mere 15 lbs of green manure with inoculant produces up to 20 lbs nitrogen by autumn.

Inoculant refers to the Rhizobia strains of bacteria that partner with the legume to fix nitrogen. For this cover crop seed blend, you want the specific species for inoculating fava and Austrian peas. AK Mill & Feed sometimes stocks (especially in the spring) the proper Rhizobia inoculant for these legumes. Find it as a very small packet of powdered inoculant on the retail seed racks called Burpee Booster. It will look something like this.

For larger quantities of the proper inoculant, order from Peaceful Valley Farm Supply, www.groworganic.com . An example is Exceed brand packets.

To use inoculant: spritz the seed to moisten, then sprinkle inoculant and mix. Now you are ready to sow your green manure/cover crop.

Please note that Rhizobia inoculants cannot be saved for the following year; they are only viable for one year.

Thanks to Peaceful Valley Farm Supply for the 3 great videos to watch. They are short and excellent. All at www.groworganic.com/videos

1. Cover Crops for the Garden
2. Garden Planning & Crop Rotation
3. Green Manure

Read & Learn More in this excellent reference by SARE
(Sustainable Agriculture Research & Education program www.sare.org )

GoodEarth GardenSchool