I will start with cover crops. I currently prefer mostly daikon "tillage" radishes. They winter kill here in December and leave a soft cover during the winter. They till deeply like earthworms and enrich the soil with organic matter and up loaded minerals from down deeper and carry some nitrogen to the next crop. These need to be planted by Sept. 10th and best if planted by mid August as they can attain a larger size before winter kill. It is best to not seed too thickly so the individual plants can be robust...5 inches apart each way is good. If these radishes are planted in spring, they just quickly go to seed and do not develop their vaunted root system.

I have planted some white mustard in very early spring. It makes a huge growth quickly so be prepared to cut it down early. I left some to bloom...the bees love it. I would not let it finish seeding.

I have tried rye and wheat. Rye is a real bear to kill in the spring.

I read about the Rodale Institute's experiences in roller crimp and plant in one operation. They sure had their troubles with that. Usually they did not get a good kill on the rye and had to herbicide it. This usually meant that the crop was planted late when often the temperatures are soaring and the soil is drying...and a bad stand results. I would suggest sacrificing a bit of growth and get started sooner.

The Rodale Institute along with researchers from the USDA sustainable agriculture study group have been woking on methods of using cover crops as mulches for a long time. While some people apparently believe crimping those grain crops should be an end to all problems it has not been so, although crimping has been a help in many ways. It may depend on which Rye one grows but I never had a problem with the Cereal Rye I grew stopping growing when I knocked it down in the spring. Annual Ryegrass can be.
Keep in mind that it was the USDA research people, not the Rodale Institute people, that sprayed the herbicides to control "weeds" not controlled by the mulch generated.

Here is a link that might be useful: Cover crops as mulch

I use rye /turnip/beets/ need to find a roller

At the last two "Acres USA" conferences a university teacher who also farms reported success with using very mixed cover crops with 10 to 20 species. The theory is that each cover species attracts a different mixture of microbes in the root zone, thus more species means more biodiversity. Now, given that crop plants need soil microbes for nutrition and protection, and that different crop plants also have different microbe needs, better growth is expected. I have had a somewhat different approach that leads to the same recommendation, as follows. There are at least 6 different reasons for cover crops, and in the literature each reason has a different (but overlapping) selection of species. But everyone needs soil builders, nitrogen fixers, and pathogen killers (mustards good here), so mixtures should make sense for all. My problem has been that some cover species have different best planting dates, but compromises can work. Regards, Peter.

Many farms do a mix of cover crops, especially no-til farmers who desire a mix of taproot forming crops to break up their soil.

Mixes of rye grass + various clover types + taproot radishes + winter peas are quite common compared to monoculture cover crops of the past.

Mixtures complicate the timing of planting sometimes and type of seeder perhaps and perhaps the offing of them. I think it also enhances the selling of fancy mixtures. Still, there can be advantages if skillfully done.

I've sued a simple, mono cover crop for a number of years now and like it very much for what I want and able to achieve, oats. for my location, the seed is sown (with my Gardenway planter) as close as possible to Sept. 1st in order to get lots of top growth before killing frost but not so early that the crop goes to seed. for me, the oat crop does 3 things primarily. 1) takes up N in the soil from that years veggie crop remaining in the soil and puts it into the tops that will be returned to the soil in the following Spring. 2) mellows the soil very nicely for subsequent cultivation. 3) suppresses Fall weed growth.

This year I tried another twist in cover cropping by planting soybeans in May (I think) and grew them until the pods were getting about half full, then, I ran the tops through the shredder and dumped the good stuff back onto the soil and turned it in prior to planting the oats. The beans had plenty of time to nodulate and form an extremely dense canopy that suppressed ALL weed growth. following the beans was the oats, I think that plot is going to be in excellent condition for next year. Never thought of 2 successive cover crops in the same growing season before, it was a lot of work! Maybe thers is a better alternative growing one crop like Hairy Vetch for the entire year. I'm still not too old to learn but old enough to look for ways to get where I want to go and not be so damned tired when I get there to enjoy life :)

Happy planting,

Michael