Grow a Cover Crop
A Blend of Seed for Alaska Soils.
Author Ellen Vande Visse
You’ve heard me preach—build your soil fertility with cover crops.
Revitalize your worn-out soil after last year’s growing season. This is the heart of organic growing.
But there are always the questions…
Which cover crop for Alaska?
When do I plant it?
Will it become invasive?
What about high shipping expenses?
Well, I recommend a cocktail of cover crops, not just a single one like rye grass. I worked with Alaska Mill & Feed to carry such a cocktail. I provided the formula, and AK Mill has blended and packaged it for the last few years. It’s called Alaska Soil Booster. Though it was briefly out of stock, I’m told that Alaska Soil Booster will be available again this spring (2025)
This Cover Crop or Green Manure seed combination is specially formulated for Alaska farmers and gardeners. Sold in 6lb jugs, 20lb bags, 40lb bags, or custom large quantities. Contains fava bean, oats, and Austrian pea seed.
For a Green Manure: Green manure refers to chopping and turning the cover crop under the soil when it’s still young and tender. 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, grow, and then 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.
What you gain by sowing & growing Alaska Soil Booster as a cover crop or as a green manure:
Increase in the humus layer of soil
In-place production of organic matter plus nitrogen (pounds of it!)
Increased populations of beneficial soil microbes and earthworms
High germination & performance in cool and cold soils
Weed-smothering
Minimize wind & water erosion
improve tilth
Draw up subsoil minerals, & accumulate them in the topsoil
What you don’t get:
a. Invasive species
b. Re-sprouting next spring. This annual blend will “winter-kill”. You don’t fight a living mat next growing season.
The Process
–Sow (with inoculant for bean & pea component)
–Grow to maturity or
–Do a green manure by cutting cover crop while still 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!
When you put this area back into production, you’ll have reduced the amount of compost and fertilizer you’ll need.
The Timing: Six Strategies
1. Before you plant a main crop
a. Delay your intended crop by 4-6 weeks while you cover-crop the area. Then chop & drop. Now plant seeds of your crops into this chopped mulch.
2. After the fall harvest
Follow your vegetable removal in the autumn with a cover crop. Example: beds where you harvested carrots & potatoes.
3. Under-sow an existing crop: interplant a living mulch amongst crops as they grow.
a. Plant leaf lettuce under pea vines to shade soil & suppress weeds.
b. 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.
c. Experiment with your own ideas.
4. Spot treatment
Fill empty spaces as you harvest (e.g. cabbage, cauliflower) with cover crop seed.
5. New plots
Prepare a new field, high tunnel, or lawn area with a full growing season’s worth of cover cropping before cultivating a garden vegetable, flower, or turf crop.
6. Do one section of the garden per year
Take 1/10th or 1/4th (for example) of your garden out of production for Year 1 and grow three successive green manure crops in this section. For Year 2, rotate to next section, while putting the first section back into production.
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 desk.
Sowing depth: 3/4” to 1” deep.
Apply with the proper inoculant (see below) for this blend’s legume components.
Do the math — A mere 15 lbs of green manure with inoculant produces up to 20 lbs nitrogen by autumn.
Cover crop maturing:
Fava, oats, pea
It will winter-kill, will not come back in the spring
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 bean 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.
For larger quantities of the proper inoculant, order from seed companies like Territorial or 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 )