Cover crop (green manure) question

I just built the walls (brick, nothing fancy) for a couple of small-med. sized raised beds in my front yard. I don't think I'll have enough time this fall to undertake all the planting in both beds, so I'm going to plant a cover crop in one of them for now. FYI, I built raised beds (not terribly high - about 15" above ground) because my native Houston 'black gumbo' (as it's called down here) soil is solid clay... I've read that certain cover crops can be very beneficial to clay soils (e.g., they help break it up, improve aeration?), so I'd like to give it a shot. Here's my question... should I seed the ryegrass (or whatever) directly into my native soil (it's been tilled, but no amendments/compost/topsoil added yet), or backfill the bed with a "good" soil mix and plant the cover crop on top of that? Thanks!

What kind of temperature extremes are you looking at?

I would try something that shades the soil, adds lots of organic content in the way of roots, but has almost zero chance of popping back out once you clear the beds for the plants you want next spring.

My personal favorite: yellow squash. One plant can saturate the ground with roots 5' from the crow of the plant and several feet deep. Then when you yank it out, those roots have already aerated much of the soil and they decompose quickly. Chop up the leaves and use them for compost in place.

Could also try alfalfa, and I think it would die on its on by June, but you might ask your county extension agent or someone at your local seed store. Could also try your local starbucks for used coffee grounds which can be tilled right into the soil without composting or a horse pasture(be sure to compost to about 140 degrees or you will end up with their weeds). Could also try grass clippings and crumbled up leaves. If there is a Texas road house restaurant around you, you could talk to the manager about saving peanut hulls for your garden. Any of these should help improve gumbo. If you use sand, be sure to use enough to make it at least 50% sand and no more than 50% clay in your beds or you could end up with a concrete like mix. Take care, Mike

kc, have you seen the cover crop information at Peaceful Valley Farm Supply?
They have an extensive assortment of cover crop seed and blends. I use the Soil Builder Blend and sweet clover usually. There is a lot of information on their site and in their catalogue.
http://tinyurl.com/yn3dcc

Fill the beds with what you want for a growing medium and amend as you wish from now on. A good green manure cover crop this fall would do that fill dirt a lot of good. We have black gumbo too. It drains so poorly as well as setting up hard as a rock when dry. Our beds are concrete blocks set on the side to that the holes are up and down. That makes them about 8" high. We tilled most of the ground level with the farm tiller behind the tractor before setting up most of the beds. Some of the others didn't get that because of location and muddy weather when we built them. We have to fill most if not all of the holes or the fill dirt will push them over. Then we plant some kind of annual in every 3rd hole. That gives me room to sit or kneel between the plants. Every couple of years we have to lift the blocks out of the soil to keep them the same height above ground.

Brick? Nothing fancy? Sounds pretty fancy to me. I, too, have experience gardening in gumbo. It is amazing stuff, but can be a bit depressing to deal with. My feeling is that anything you put in the ground that will grow for the next few months will be wonderful. The yellow squash recommended by Greenjay is great if it will grow at this time of year in Houston. I agree with GM that you should look at the Peaceful Valley Supply or any of a number of others. Many seed catalogs offer seeds for cover crops. Johnny's has a number of them. Rye grass works great. Then you till it in. Alfalfa is a perennial, as I understand it, so you would have to really till it in to kill it. Or you can mulch the whole thing a foot deep ( or more) in leaves and grass clippings which are probably abundant where you live. The bottom line is that you should get as much organic matter in as soon as possible. The rye grass has the benefit that it dies out before long. There are other plants that do the same. Just work in as much organic matter as posssible.
You can't fail. My experience is that if you can keep the weeds out and get it pulvarized a bit, gumbo makes pretty good soil.
Consider this. A lady in California had a serious problem. Concrete in her back yard. She built or had built raised beds, certainly no taller than yours, which are rather tall for raised beds. She filled them with the best soil she could come up with and planted her garden. It has now worked great for years. I think I read this in Kitchen Garden some years back.
One way or the other, gumbo is a better base than concrete and this lady did fine with concrete. And I don't think her beds were as deep as yours. I say just put in all the organic matter you can come up with and your plants will break up the gumbo.
Best of luck.

Most gumbo is a spectacular building block for fablous soil. You will need drainage so raised beds are the best and I have used 5 to 10 parts of wood, sawdust, compost, etc to make the soil great. Many discussions have been described in detail refer back in this forum.

Soferdig, How would I go about locating the thread discussions about composting? Is there a search feature on the thread or website, or would I just need to hunt every listing for titles that say composting? ~~~ Carol

http://davesgarden.com/forums/f/soil/ This is a good one and lots of ideas on other compost ingredients. I'll look for a couple of more.
http://davesgarden.com/forums/t/625016/

http://davesgarden.com/forums/t/633363/

This message was edited Nov 4, 2006 8:48 PM

Thanks I'll read over the start a compost thread.