Cover crops can serve either (or both) of two purposes--After you've harvested and have a bare plot, growing something there can help hold soil in place-- Erosion can be a problem if the plot is on a slope or is subject to high winds over the winter. You'd leave the crop in place and till it under in the spring....or if you're not particularly worried about erosion but just want to build up the organic component of the top soil (build humus) you could till it under in the fall and give it extra time to decompose.

Legumes add more N to the soil than other classes of plants, and if you use bush type, they won't foul your tiller like longer stemmed plants can....I just go to the Dollar Store and buy a bag of about 4 million beans and scatter them about. They take 60-90 days to mature, so they'll freeze here before they can be harvested. It depends on where you live.

 

It may be a bit late to find any seed, and late for starting any legumes for nitrogen fixation, unless you plow or till your garden later than usual next spring, so as to give clovers and other winter hardy legumes to fix much nitrogen thru the roots. But you could get a sowing of cereal rye for biomass, root growth to break up soil compaction, and erosion control.

As it probably is in your area, the same as mine, the main problem is to find any garden sized quantities of cover cropping/soil building seeds---and you will go broke getting any from the catalog companies. I was lucky enough here to find a couple of farm seed stores that could weigh out small plastic bags of : crimson clover, yellow sweet clover. mammoth red clover, turnips. Then I get a 50 lb bag of horse oats, and then I pick up as many pounds of Great Northern beans from the grocery store as I need and mix my own , to sow into and on top of fresh tilled soil. One thing I have done is to rotate plats each year, so there will always be a soil building plan. An early fall sowing of this mix will also give you some nitrogen and biomass and soil compaction reduction, but you have to get an early start, especially after sweet corn and green beans.

Another thing you can do is to buy some bales of second cutting alfalfa/grass mixture hay to use as mulch for your onions, garlic, tomatores, cole plants, etc. BUT--it should be second cutting to get a higher proportion of alfalfa(nitrogen) to grass, and by using alfalfa and grass, you can be assured that no Roundup(which kills grass) and no lawn /pasture broadleaf weed killers(alfalfa is a broadleaf) have been used. Sure you'll pay a little more, but you won't smell like a horse when you spread it.

Evaluation of Cool Season Cover Crops in the North Central Region - MCCC (msu.edu)

Your deer will love you, too.

geo

 

When's your first frost?... I agree with winter green manures/cover crops for some things but not building organic matter. They just don't generate enough dry matter/biomass unless they are grown over the summer... and even then it has to be well managed forage sorghum or sorghum-sudangrass that gets you up to at least 10 tons dry matter per acre to be worth taking land out of production. Vetch and peas do generate a significant and useful amount of nitrogen if you can get them in early enough and allow for some spring growth. Some people mix cereals in as a nurse crop to give the legumes something to climb up on. You should inoculate the legume seed if you aren't aware of a related species(that uses the same nodulating bacteria) being grown on that ground within the last 5 years. You can buy seed in bulk and then keep it double bagged in a freezer until you need it. Inoculant should only be bought for use the same season.

https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053140.pdf:
"An acre of soil 6 inches (15.2 cm) thick weighs approximately 2,000,000 pounds. One percent SOM, therefore, weighs about 20,000 pounds (dry). Under normal conditions, 10 pounds of organic material decompose into about 1 pound of organic matter. Thus, at least 200,000 pounds (100 tons) of organic material must be applied or returned to the acre of soil to produce 1 percent stable organic matter" (“What Does Organic Matter Do In Soil?”; Funderburg, 2001; Samuel Roberts Noble Foundation)

 

Some deer feed plot mixtures make good cover crops. They are easy to find this time of year and don't cost a whole lot.

 

I think the OP is referring to a few hundred sf of garden plot, not 600 ac of row crop. Just letting the weeds grow and then tilling them in would suffice.

Legumes don't add nearly as much N as we'd like to think Crop Rotation: Do Legumes Really Add Nitrogen to Soil?

NMSU: Nitrogen Fixation By Legumes Most of the N in a legume goes into the seed. The roots & veg growth have no more N stored up than any other plant , so, unless you grow them long enough to go to seed, and then till in the seeds, you're doing no more good than just tilling in weeds.

 

Legumes don't add nearly as much N as we'd like to think Crop Rotation: Do Legumes Really Add Nitrogen to Soil?

This link only says they don't add much nitrogen if they aren't inoculated or the soil has been heavily fertilized with nitrogen.

NMSU: Nitrogen Fixation By Legumes Most of the N in a legume goes into the seed. The roots & veg growth have no more N stored up than any other plant , so, unless you grow them long enough to go to seed, and then till in the seeds, you're doing no more good than just tilling in weeds.

The article states that removing the grain/seed from a mature grain legume removes most of the nitrogen. However most legumes are not grow until mature for green manures/cover crops. Until they form seed the nitrogen that would go into the seeds is present in other parts of the plant. It doesn't just appear like a step/Heaviside function right before the seeds.
Legume forages and hays are generally harvested before they produce seed, and contain high levels of protein. The nitrogen in this protein comes from fixation by the plant as most are not fertilized with nitrogen.

Vetch is about $2/lb in bulk and you need about a pound per 1000 sqft. You could buy a 50 lbs bag and slowly sell off the extra to other people locally via FB marketplace and Craigslist until you got down to whatever you think you would use in the next 10 years... then put it in the freezer double bagged.

 

Most of the deer food plot mixes I have seen are meant to cover 1/2 acre or less, not hundreds of acres. They give the sq ft coverage right on the back. Wouldn't be too hard to use part of a bag and store the rest in a refrigerator. They usually contain less than 2 quarts of seed.

 

This year I have turnip seeds to give me a cover crop. Basically as I harvest the Fall vegetables I will sprinkle the seeds on and let them be. I will turn them in in the spring and it will prevent my clay soil from packing down and getting hard

I do not space the cover crop seeds like I would if I were growing the turnips for vegetables: I just scatter them and what grows, grows.

A youtube called Deep South Homestead used turnip seeds for a cover crop and the deer came and mowed them all down. He did not mind at ALL because they left their manure behind. Also he got a deer when hunting season opened.

I do not do a cover crop every year: far from it! But the seeds were half price and any kind of a cover crop will improve your soil.

 

They do produce field peas in your region... you may be able to get a 50 lbs bag at an elevator for cheap whenever it's harvested. They are better in some ways than other legume seeds because they don't have all the antinutrients requiring heat treatment before feeding to monogastrics... or lots of fat to go rancid. Not sure how easy they are to harvest on a small scale though.

 

You should not get harvestable peas this year, of course: there is not enough time before winter ends the growing season. And I might be wrong but I believe that winter will kill the peas in your area

speaking from experience, a cover crop will till in more easily if you mow it first. By chopping the vegetation up it is less likely to wrap around the axle of the tiller

 

@Snowfan, did you decide to plant a cover crop?

 

I did not. I got sidetracked. It happens all the time.