Generally when you plant a cover crop you would knock it down, or turn it in, before the plants set seeds. The Cereal, or Winter, Rye I plant is cut while still quite green and before any seed heads form and while I allow the Buckwheat to blossom that is cut down before seeds set, too. If you do not let the cover crop, whatever it is, set seed there will be no problem with it self seeding.

i'm going to try crimson clover myself this fall, this will be my first time trying a green manure. the clover is supposed to flower around april-may, and i plan on tilling it under about 2 weeks before i plant. since the flowers never turn into seed pods, there's no problem with self-seeding.

OK. Well, maybe my concern is that here in the south, maybe some of these will continue growing throgh the winter, and even if I cut early spring, there may still be time for them to set seed.

Compounded that, is my ignorance as it relates to when something actually sets seed. I have a lot of weeds in my yard that will attest to that. Can I look at a plant (and/or time a plant) so that something tells me without a doubt that it has set seed that is viable? I'm interested in this also, because I'd like to put weeds in my compost pile, but currently have no way of knowing for a fact if they have set seed. Do plants only set seed in the spring? If I can catch a plant blooming, does that mean that seed has NOT set yet, and therefor, if I pull it up in bloom that it's fair game for the compost pile?

Any other hints about handling plants without worrying/wondering if they have gone to "viable" seed? I'm assuming a plant could LOOK like it has seeds on it, but the seeds have not become viable (yet?)?

Can I look at a plant (and/or time a plant) so that something tells me without a doubt that it has set seed that is viable?

First it flowers, then those flowers form seeds. If you plant a cover crop and allow it to flower you are too late and now have a weed. Seriously.

This may not apply to every possible cover crop, but many plants which become regarded as weeds do so because even when cut down while in flower, they have enough energy to form viable seeds.

The only way to be certain a plant won't come back from seed is to kill it before it flowers.

Again, not every plant has this tenacity, but if you want to be safe, do not let it live long enough to flower.

Any cover crop you plant now should be one that will survive the winter, that is why it is there to protect the soil during the winter. None of the cover crops I know of will flower and set seed during this time and not all of the available cover crops need to flower before developing seeds. The grains for example do not flower but set seed, but even if those plants started to do that you would have ample warning to cut them just buy watching the development of the seed head.

justaguy & kimmser-
OK. That clears things up for me a LOT. Wouldn't have even thought about the fact that some of the flowers could actually produce seed when dying....

Would this apply to being in the bud? Humh, I'm thinking I just figured out what the saying "nip it in the bud" really means.... well duh?

As far as grains go, wouldn't they develop something that looks like a seed head before the seed actually became viable? What would be my "Eddie it's time to cut that grain NOW" or you're going to be wishing you did!

Is hairy vetch any different? It was mentioned to me that it can be especially problematic for the south.

Also, is there any distinction between the clovers. Aren't they typically perennials? Do they also flower and then set seed? Do the same rules apply?

If something is a perennial, is there any way to ensure that it does not "come back" the following year?

Thanks again!

Perennials do not seed to grow in succeding years. The plants are hardy and frost and freeezing weather do not kill them. Perennials can grow from seed but it is not necesary, once they are planted to sustain growth.
The single best way to stop a perennial from regrowing is to uproot it.

Suggest you plant your winter garden anyway you wish. Rhizo says it best..."I have a headache...".

BTW, there is one legume that the backyard gardener can use easily as a cover crop here in the south that will not cause weed problems. Let's see if you can guess what it is.

It is edible. The shoots are very tasty in salads.
The seed needs to be inoculated.
It is sown in Jan./Feb. in the south.
It is an annual, cool weather crop.
The 'bush'/lower growing type is generally used as a cover crop.
Can be tilled under but best pulled and added to compost.
Can be purchased in bulk at feed and seed stores.

What is it?

Chickpeas?

Take two aspirin and call me in the morning....
I was gonna say soybeans, because I know some people eat them. However, I don't (intentionally). However, I don't know when they are started... kind of thought they were basically a weed around here that grows all year long except for real cold weather.

I don't even know what chickpeas are. Is that some kind of norhern food (sorry... couldn't resist based on some of our other "converstations" on here). Seriously, I was thinking that maybe they were garbanzo beans... you know the big round beans on the salad bar (of which I don't partake in either).

Something tells me tha cabrita is probably right. I'll apologize for myself in advance, because I really just started eating vegetables.

So what about the hairy vetch nandina? Why is it potentially problematic for me (specific to the south?)?

Sorry, I am now in the acute migrain headache stage. Suddenly the mention of clay beneath the sandy soil! Makes a big difference as to how the garden is handled. And the determination to use an invasive vetch. No thought as to how many chemicals your neighbors will use trying to control it.

Well, then take 2 shots and we'll talk some more tomorrow.

Well, the "clay" may be a non issue after all. You see, I didn't have a tiller when I did my first garden plot last year and I was bringing up some more red type stuff from down around 8 inches. So, based on some other land around the house (pines are planted on) I just was thinking that it was clay in my garden (I was trying to not turn over the soil because I was concerned about mixing in the clay at the time).

Well, I ended up purchasing a used tiller (don't hate me for it (har)), and well, after breaking up down to around ten 1nches or so, it's NOT clay where my garden is, but it's some sort of other material that's probably not pure sand.

So, now I have the pine bark fines tilled in and it looks pretty "good".... whatever that means. Not pure sand anymore anyhow.

So, what would be the distinction between how sand with a clay layer (say ranging from 6-10 inches beneath the sand layer) would be treated? I'm going to be running into that soon enough in some other areas I'll plant.

Also, you keep alluding to problems with the vetch. Spit it out. What's the big deal with vetch in he south vs elsewhere? I don't technically have neigbors (1.5 miles away), so my biggest concern is encroaching into my yard, the pinelands or the hardwood land? I'm seriously interested in your take on this because you've lived here.

So, did anyone guess right?

Hardly an expert on the subject, but for the last 4 years I've been using Fall cover crops on my garden and I'm guessing that I'm within 150 miles of you.
I use a combination of Cereal Rye and Austrian Field Peas or the Rye and Hairy Vetch. It won't grow much during the Winter but it stays green and maintains itself in a seemingly brown landscape-which is great. I love to look out the window and see green 12-18 inches high, densely packed plants, that represent my future garden.
Spring hits, the Rye goes shoulder high. I start knocking it down with my Troybuilt Pony when I see seed heads start to develope. I only beat it down and incorporate it 2-3 inches deep. Soil biology takes over. Two weeks later, till again at same depth and plant.
My crops have got increasingly better, the soil has gone from bright red to dark brown. I do use leaves and a little Lime for further ammendment.
Back OT, I have never had any problem from cover crops trying to re-grow.
Good luck,
Steve

Steve-
Apologies for the late reply.
Thanks. What you say is encouraging to me. I got my cover crop seed in the mail yesterday and plan on getting a cereal rye/hairy vetch mix in the ground this week. I was told end of the month would be OK, so I hope everything will work out.

Also plan on planting white clover under all my brassicas in the next month or so, and I hope that won't be too late either. Have you had any experience with it, and could give me some deadlines as to when I need to get it into the ground?

Thanks!