What is the source of your manure?

If it is from stabled, alfalfa-fed horses, there is no need to compost it. You can use it FRESH. Just put it directly around the roses as a mulch.
DO NOT pile it right on the canes. Rather, back it off at least a few inches.
If you are not getting rain, I like to water it in some. The amount is a matter of choice, and how much you have. A good big shovel-full, ideally, per plant.

If these are pastured horses, and they are eating weeds, yes, it should be composted thoroughly. I don't think leaving it in bags would be sufficient, but others may know better.

Jeri

You're not supposed to feed horses alfalfa, though almost all the fields around here have some in it. Makes them founder.
We just go out and get some wagons full and mulch everything in the fall. This is a trick I learned from an article about a Chicago Arboretum.
Horse manure is very mild. It freezes and rots all winter, holds in moisture and is already there doing its job in the spring.
I suppose we get four pickup loads a year from one horse.
If you want manure that really works, keep rabbits.

The main advantage of well composted horse manure is it kills off the weed seeds. I have gotten around this by topping the horse manure with mulch. Does wonders for my clay soil.

I just drive down the canyon road to the stables, get Mark to help me fill up the trailer with the stuff which is in a huge pile outside. Don't know how old it's been there, but they are thrilled someone wants it and is willing to take it off their hands. Don't know what they're feeding them. I put it from the truck directly on the roses (not touching the stems, like Jeri said) and if there's too much left over by the last bed, I use the stuff as a mulch...the roses do really well. I have had not nearly as much time this season to garden, and the roses have been better (except for the deer!) than ever on this "neglect"...I just put on the manure and make compost as I can. (o...and I don't plant fuss-divas...)

Hope this helps.

Jerome

Keeping manure in sealed containers is not good. It will quickly go anerobic and can really produce unpleasant results. That's a pretty basic composting issue. If you are going to compost it, compost it right. Otherwise, you're better of using it fresh with plenty of water.

Thanks everyone for your responses. I think I might try the 'mulch on top' idea, since the horses are being fed both alfalfa and field greens.

Berndoodle--how long can containers be sealed before the manure goes anaerobic? The only reason I would cover them is to keep the rain out. I would take the covers off in between rain storms, so if the anaerobic process takes only 24 hours or so, I will use it right away.

Manure is wet and heavy and goes anaerobic fast. When it comes out of the horse, it's already full of a wide range of anaerobic bacteria.

What about just putting it around the roses and throwing some Preen over it next Spring to inhibit weeds?

If the field is mowed or grazed short & well managed, the weed seeds should be minimal anyway.

Cheers,
Michelle

What Michelle said. Why store it? Dogs hungry? Otherwise, pour it into piles and compost the right way, in contact with soil (soil organisms help), turning for aeration with a pitch fork to save your back, watering to keep just moist, adding lawn clipping for high nitrogen if it cools down and your shredded bank statements and other personal data for dry matter. Or put it on straight but water it in. This assumes you are not talking about stable bedding with horse urine. That would have to be composted with water. Too high in salts for SoCal in a drought, too high in salts for anywhere anyway.

The reason it must go into containers is because I live in the burbs and do not have any room to let it sit out and compost. Also, I will be getting at least 1 cubic yard of the manure, so I plan to apply it over the period of a week or two. Thus, placing it in the containers makes it easier for me to run a few wheel barrows of it to various locations per day. Since we are in our rainy season now, I did not want the containers with the manure to fill up with water. Perhaps that is not a bad idea though. In any case, I will step up my application program, so that I use it up within one week if possible, time allowed.

my dad puts fresh horse manure around my mom's peonies. He would scoop out the trailer after a ride. Hasn't killed them yet. actually they really look nice.

You do not want the containers to fill up with water. A bushel of it when it's fresh is heavy as it is... Keep in mind, a cubic yard of it, fresh, will be a pretty small amount when it's either aged or composted.

Just thinking of your back!

Cheers,
Michelle

I think I will just apply it as fast as I can and hope to beat the rain. I presume that the manure will be from stall cleanings, so there will be urine in the shavings/hay. If I am lucky, we will get rain shortly after applying the manure. Otherwise, I will water it in myself.

I forgot to mention what Michelle said- pre-emergent is also useful as a preventative.

If the manure has urine and shavings, it must be composted. Be careful not to put it on your roses or any plants straight.

On the other hand, if what you have is the stuff that comes straight out of the back end of a horse, you do not need to compost. Clear enough?