Try this question on the composting site. I have always heard rye and clover.

THere is one thing: Many of those "native/naturalized weeds" are some of the best cover crops! Also, in theory there are no native weeds, just plants that we dont want in the yard.. For some people that can be oak trees! First off are clovers - White and red. Cold hardy, attracts bees and parasitic wasps (beneficial). They have massive roots for soil retention. You can make tea from them as well. They are also a nitrogen fixing plant which aids other plants. Dandelion - Thats right, dendelion. One of the earliest flowers here, so it attracts insects first thing. You can make butter wine and eat the young leaves like lettuce. The best thing is the fact their tap root goes so deep it collects minerals from hardpan and sub soil. They basically aerate your soil while putting minerals and nutients on the soil surface. The thing is they will eventually be ut competed wiehn your soil profile is filled and undisturbed. Strawberry - How can you get any better then a ground cover plant that fruits? Strawberries are native to much of the US (F vesca) and make great ground covers. The varieties that produce runners will ensure that you really dont have to do too much to get them to spread. Strawberries have roots that can go 10 feet into good soil. Lupine - These guys are awesome plants. They fix atmospheric nitrogen (like almost every legume), are native, hardy, produce massive root systems and have some of the best flowers in the garden. Bees LOVE these guys along with a plethora of beneficial insects. You usually see them in ditches but they are not limited to moist soil. THere are also a few shrubs that will work with coppocing ( basically cutting them down by half or more in early summer). The one that comes to mind for up here are caregana AKA siberian pea shrub. Hardy, can take being cut down to the ground and regrowing can be used as fodder as well. Once summer comes unto ful swing and these guys are floweriing you cut them down to what ever height you decide and lay down the cut material around the trees as mulch. These fix nitrogen as well. They can also be hacked down every year and still survive for 20 - 50 years. You should also use some annual cover crops like vetch. Any pea will do this as well. The same with beans. At the end of the season after you harvest, in the first few years of establishing the yard, these should be dug into the soil, and then use a cold season grain planted on top to be cut in the spring. Alfalfa is great as well... Perrennial, large roots, hardy and fixes nitrogen.... Interplanted in all of this should be flowers. I hated flowers when I first started gardening but the more i put in the more insects arrive. The flowers will attract beneficial insects to aid in pest control and pollination. These can be short native shrubs like some rose species (which also have hips you can eat and cook with). Things like flax, poppy, herbs (rosemary parsley, mints, oregano, lemon balm etc), native and non native lily and iris, black eyed suzan, coreopsis..... at this point the list is endless and should be done to personal taste! Some perennial grasses will work as well. The thing is in terms of cover crops the trick is diversity. Diversity can protect and build your soil and help protect your plants from stress therefore disease and infestation. I personally advise against only lawn. It causes its own problems. You want a variety of root depths to ensure proper soil retention. Only grass is generally one level of root structure. The higher the diversity of plants and trees, the more root structure therefore the greater soil retention.

This time of year in our zone it is almost impossible to get a cover crop to develop without extensive watering and then it just shallow-roots. It is just too hot. Later this fall, no problems, and any of the clovers is an excellent choice. You could accomplish the same thing with a good thick layer of organic mulch - compost or composted manure (more N), even chipped hay. As it decomposes it will provide nutrients to the soil. Other option for nitrogen is alfalfa meal/pellets. Put it on now and then plan to plant CC this fall. But keep in mind that N is seldom tested for professionally simply because it is so volatile and quickly dissipates. So they usually just make the flat recommendation to add N even though there may be plenty there - it just won't show up in the testing. So don't go overboard with N additions or you may create even more problems in the long run. ;) Dave

Yes, absolutely while things are still growing. I even have one friend who scatters oats in her perennial bed. The bulk of my perennial beds are in my front yard, streetside, so I don't do that cause it looks like the devil. Of course, you can't foresee what the fall weather will be like, so some years you will have planted too early, some too late. I guess ideally you want close to a month to get good growth. So figure about a month before your frost date. Too early is better than too late. I sow each bed individually according to what crop is or was in there. Starting in August, whenever I pull something out, or it starts to slow down, I sow oats. If I was really organized and did a lot of successive seedings of lettuce, spinach, etc. I probably wouldn't want to start so early, but then I do have a veg garden that is really too big for me, and the oats help keep the weeds down. I also use straw in my paths. (The oat plant really IS my friend. lol!) One year we had a frost the second week in Sept. This year, not till November. And that was great cause I didn't FIND my bag of oats until Sept! All that said, one of the advantages of buckwheat is that it is said to have alleopathic qualities, that is it inhibits subsequent weed growth even after it is turned under. However, on the down side, I have been told that if it is let go to seed it can become a nuisance. Good luck!