Also....
How much of a nitrogen source will this hairy vetch be if I allow it to grow until spring?

I mean, will this be able to be the only nitrogen source my vegetable garden will need for the following spring summer? Or will I have to use an additional form of nitrogen during the growing season?

Also, how many years before I will be able to notice an improvement in tilth due to the incorporation of the vetch and other green manures? I mean will it be immediately apparent or is it going to take many years to improve the organic content of the soil?

Hoping to be able to use cover crops as compost rather than making compost in the traditional sense. Is this unrealistic?

Having a good, reliable soil test done would be a really good idea since knowing what your soils pH is, and what if anything would need to be done to correct any probem with that, can help understand why some nutrients might not be available to plants. Adding Phosphorus to a soil with too much is not a good idea since that is, along with Nitrogen, a major source of pollution in our lakes and streams (our drinking water). Other things you can do to know your soil better are these simple soil tests,
1) Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart.

4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer you soil will smell.

5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.

Nitrogen availability is more dependant on soil bacterial activity, soil temperatures, then anything else, unless one uses highly soluble sources of N from synthetic sources. Adequate levels of organic matter in the soil will help provide sufficient amounts of Nitrogen to your plants.

Here is a link that might be useful: Clemson CES

emyers: I think the soil test and planting a cover crop are separable issues. If you haven't had a soil test for four years you should have one. Four or so years is a good interval. But you can proceed with improving the soil with a cover crop without knowing how the soil tests. If you use hairy vetch or any legume for the first time you get the best results by innoculating the soil with the species-appropriate bacteria. Don't panic; the innoculants should be available from your cover crop seed source. If you can't get them, your first year crop mightn't be so hot, but subsequent years should be fine.
I find that suppressing weeds is more of a problem than lack of nitrogen, so I have begun to use 2 or 3 parts cereal rye to 1 part hairy vetch. In any event, you should get the vetch sown by the end of this month. It sets nitrogen best when it flowers, which would be late spring or early summer where you are. Finally, if you use cereal rye, be aware that it can kill off vegeatables just as easily as weeds. For this reason, you should plan to follow it with large seeded plants such as peas, beans, potatoes, or established plants such as tomatoes or peppers, rather than small seeded plants such as lettuce, cabbage, celery, and their cousins. Regards, and good luck, Peter.

kimmser/peter-
Thanks for the interest and info.
I recently had a soil test done (my first one) and everything was in the high range EXCEPT Potassium.
However, for whatever reason, my soil test results did not include the amount of nitrogen. I notice on the soil report that nitrate nitrogen is listed but there is no info about it in the results column. I was thinking that NITRATE nitrogen would be something that applied to synthetic fertilizers moreso than organic... but I really don't know.
So, I don't know how much nitrogen is already there. Do I need to find out? How do I find out (soil test is done by Clemson University).

The only other unknowns are sulfer & percentage of organic matter because apparently they require separate tests.

The PH is 5.9 with a buffer ph of 7.75 and Clemson does not recommend liming at this level (although it is borderline).

This test was taken prior to putting in my garden (first one this plot) and I added black kow, blood meal(5lbs/100sqft), greensand 10 lbs/100sqft)and rock phosphate 10 lbs/100sqft)at levels designed to bring a medium or low reading up to high.

So, I'm thinking that because my garden was so BAD this go round that all of these additional ammendments are still there.

So, don't really think an additional soil test is necessary but I'm probably going to get one anyone more or less out of curiousity.

Kimmser-
I did the settling out test and mostly what I have is sand. Very little organic matter and clay. Thus the reason for trying hairy vetch. I'm also guessing that there is little bacterial activity because of the lack of organic matter (thus the reason for thinking most of the "blood meal" is still there. Drains well, smells fine, no earthworms. Yeah, it needs some work, I'm starting to understand why.

Peter-
Interesting on the addition of rye to suppress the weeds. I take it the hairy vetch is slow to cover, I thought it would do ok on it's own.

Based on what I've said above, would you agree that a nitrogen source is probably not necesary.

4 years for a soil test seems reasonable to me. Sure would like to get to where I don't need them at all to understand how my soils doing.

Another apparent misconception on my part is that I'm going to be able to plant my spring garden in the plot that I plant the hairy vetch in now (winter cover crop). I was thinking I'd till it in a few weeks before last frost and everything would be better for my spring/summer garden. What I'm hearing you say is I probably need to wait.

Trying to come up with a plan that I can rotate out spring/summer & fall/winter cover crops with spring/summer and fall/winter gardens.

Attempting to figure how many separate plots I need to take things in and out of rotation so that I can get the organic matter in while also cutting down on disease because I rotate.

What's the worse case scenario if I don't include the cereal rye with the vetch? So the cereal rye actually kills weed/vegetable seeds? Certainly didn't know that. I thought it was just weed suppression because it grew fast and got ahead of all the weeds thus shading them out and or choking them or something. Is the weed seed killer nature specific to cereal rye or is it particular of all the ryes? What about mixing in some sort of clover vs the rye? My brains spinning already when it comes to scheduling.
Thanks for reminding me about the innoculant. Keep forgetting about it. Sounds like it's pretty important. Is there any info out there about how an innoculant could potentially be bad for your soil? It's not introducing something to it that hasn't been there in the past?

Thanks all!

Very few soil testing labs test for Nitrogen since the N availability is soil is dependant on soil temperature and moisture more than how much might be there. Low levels of organic matter will also influence the availability of N and you want more organic matter in your soil to feed the soil bacteria that will feed the plants you grow in that soil.
Blood meal is a very soluble Nitrogen source so with the low levels of OM in your soil that N will simply flow on through your sand with so little OM there to hold it in place. What you want to do is get the level of OM in your soil to around 6 to 8 percent.

Thanks. I'm starting to understand that now (need to get OM level up).

Any thoughts on pine bark fines?

Does this make sense...
If I make the assumption that I will till in organic matter (hopefully pine bark fines initially) down to say 6", and I want 8% organic matter, then 6"x8%=.48".

So, all I'd need to do is top dress the area with 1/2" of organic matter and till it in to 6".... then I'd be at 8%?

Is it really that simple?

If so, what depth would you recommend carrying the 6-8% down to. Would 6" be enough?

Any thoughts on how this would work with green manures/cover crops/living mulch? I mean, If I grow a cover crop and till it in, is there going to be enough material there to supply the 6-8% OM you recommend each year/rotation?

emyers: Sorry to be the one to dash your hopes, but it's generally reckoned that the most one can increase soil organic matter is 0.1% a year. For instance: I have assiduously applied 1/2" of compost every year, used mulches of shredded leaves or straw throughout, and cover crops partially on a community garden plot I rent. In 9 years I have been able to increase soil organic matter from just below 5.0% to 5.5%.

By all means take steps to increase soil organic matter, but don't overdo it. The decay system needs to be able to digest all that organic matter. You can help this with compost tea and molasses, applied in solution. The quickest way to add organic matter is leaves/straw mulches, followed by compost that has been made with lots of woody material. Cover crops don't materially increase soil organic matter becase they are cellulose carbon (i.e soft stuff), which decays too quickly to build soil organic matter. Cover crops have many other benefits though, such as improving soil structure and helping to control weeds. You need structural carbon (i.e. harder stuff) to build soil organic matter and, eventually, humus. Cover crops will decay in 30 days, give or take, while shredded leaves incorporated into the soil will decay in 90 days.

Which brings us to pine bark. When it is fully composted this is great, but raw it will take several years to decay. Problem: the decaying agents are microbes, whose energy source is nitrogen, so they will tie up the nitrogen in the soil until decay is completed. You will have a nitrogen deficit with pine bark for years, instead of 90 days if you use leaves. Regards, Peter.

Peter-
No problem with dashing hopes. I appreciate straght talk.
Point one percent per year. Geez, I'll never get to 8% at that rate.

So, the compost, mulches and leaves etc. that are in the process of decay are not factored into the overall percentage of organic matter? Then what is it?

The pine bark that I have access to are "aged", but not tecnically composted. They have been aged for 1 year plus in piles & kept moist & turned. It's also described as readily rewettable.

sizes as follows:
5-8% greater than 1/2" (but less than 5/8"
25-31% less than 1/2"
64-71% less than 1/4"
Moisture content 25%
PH 4.5

Any more thoughts on this stuff?
Would I need to be concerned about it tying up nitrogen? Lowering my already 5.9PH w/ 7.75 buffer ph?

I'm going to start another thread describing it.....

1/2" pieces of bark will still take a year or more to decay, and tie up nitrogen for all that time. Leaves are much quicker and they are free!. Regards, Peter.

Peter-
From what I'm gathering (from another thread) the pine bark fines DO NOT tie up nitrogen.

That being said, free is good, and I have access to some leaves. Would like to try some gound up leaves (run over with mower) as a mulch to incorporate into the soil early spring.

Do you have any recommendations on how thick I want to apply chopped leaves? Then, how long will they need to sit on top of garden prior to tilling in? I mean, if I mulch my garden now with the leaves, will they be ready to turn in in the early spring? At that point, will they still tie up nitrogen?