The optimal time to till manure into soil was last fall, if you were to till it in at all. What else do you have to till in with this manure? You will hear that anywhere from two to six weeks will be necessary before planting after you till this spring, but manure is always best composted beore being added to soil.

As you probably know, plant food must become available before your plants can use it. Non-available plant food will not help you. You are on the right track with the manure. But, the plant food in "green" or fresh manure is not available and does not become available until it is released by the decay of organic matters inside. Waiting for manure to rot in soil can be a slow process, especially in heavy or clay soils. You want to keep the manure in a compact built up square heap, not a loose pyrimidial pile. It should be turned from bottom to top and outside in and rebuilt every month, and sprayed lightly with the mist of your hose (not soaked). Make sure it is under cover so it does not wash out. Next year you probably should get your manure in the fall if your going to get it fresh, it needs some time to rot. Only use well rotted old manure in the garden itself, because if plant food is not available it is useless.

Jamie Wheeler is the author of "Organic Gardening Secrets", dedicated to helping you grow healthy, pesticide free fruits and vegetables at home without spending a lot of time or money.

Here is a link that might be useful: Ultimate Organic Gardening Secrets

I have tilled in raw/green manure 60-90 days & got no burn on plant & they grew well, with out added compost.

I've put fresh horse manure straight from the corral into the garden, and not had problems with burning if I till it in. I generally tilled it into the top 8" or so of soil. For me, an inch or two of manure worked well. I did not have other sources of organics, so did not use any. The greatest challenge I found with the horse manure was the huge number of seeds in the product. For this reason I've stopped using fresh manure straight into the garden. Taking the time to compost it helps to get rid of some of the seeds. If putting the manure some place where the weeds won't bother you (like an orchard) then go ahead and just lay the manure on the surface; the soil critters will mix it in.
Renais

One other reason for not being in a hurry with fresh animal manures is the safe tack of letting it sit a good long time so that any diseases can die out. This is not a problem with ornamentals but with foods it might be prudent to go slowly for the sake of your family's health. That sounded nasty. It's not meant to be. Just cautious. Horses have mighty diseases too.

I would leave fresh horse manure six months before incorporation, i.e. next spring. Quite the best practice is to compost it with "brown stuff" like dead leaves or dried grass clippings, or really any garden or kitchen waste. . Since you have lots of it, wind-row composting would be best, turning it weekly. If you have a skid-steer loader, that would be ideal for turning. Otherwise a garden fork and a strong arm. Regards, Peter.

The USDA says 90-120 days from the time the manure first hits the ground.
That is 90 day for above ground vegetables(beans) & 120 for underground vegetables (turnips,potatoes,radishes).
But I know persons who use green manure, both on top of the garden & tilled in with not problem that any of us can see in the 10 year they been using manure.

The 120 day guideline also includes crops that have the potential for contact. IOW, not just root crops.

Lloyd

Here is a link that might be useful: Guidelines for Using Manure on Vegetable Gardens