waiting period for manure; exaggerated? Or not?

I have heard recommendations to age all manure for at least six months, then till it into the ground, and then wait a month before even planting anything.

Well, as a permaculturist I don't till. I also don't leave bare ground for a month. And I build sheet mulch beds with wood chips and horse manure.

This is in a community garden I am organizing, so it is really important for me to understand. Will I create an epidemic by doing this?

How on earth COULD an organism which thrives inside an animal survive for a couple of months in a hostile outdoor environment, complete with competition by better adapted species, UV, heat, cold, and a totally different chemistry?

If the above is not sensible, as I suspect, what are some sensible rules?

You needn't fear an epidemic from horse manure. It's probably the safest to use -- very unlikely to harbor human pathogens, and also not so hot that it would burn the plants.

Cow manure and chicken manure are hotter, so that requires (a) waiting for it to break down or (b) dilution. If you have either of these available, dilute them up one part in 20 parts of water and you will have a manure tea that you can use without waiting.

Stay away from used kitty litter or dog manure. They can be a pathogen problem.

How do pathogens survive to infect? It's called sporulation

Horse manure contains a lot of viable grass seed. six months in a hot compost pile will either heat kill or germinate and smother most of those seeds, the downside of using it fresh is more time spent weeding, but in a layered system that won't likely be an issue.

The standard recommendation that I have seen as a market gardener is to wait 90 days for above ground harvest (tomatoes, peppers, etc) and 120 days for anything with soil contact (potatoes, carrots, etc). I understand that the new food rules were going to require a 10 month period, but I think that's on hold for now.

I follow these guidelines carefully because it only takes one person getting sick to ruin me (and probably most of my fellow farmers), but for home consumption you should decide what works best for you.

My biggest fear is the wormers killing my garden biology. I would wait to let those decompose unless you know the source doesn't medicate (including their feed source).

Where did the 6 months come from? Heck, I'd say a couple of days above 131 degrees will kill pathogens. The trick is to get the whole pile to reach that temperature. I look at it like shuffling a deck of cards: you can get a pretty random hand by shuffling five times. I let my pile get above 131 for three days, then shuffle (turn), and repeat.

Cornell has a good page describing the different thermal stages of compost: http://compost.css.cornell.edu/microorg.html

If you're going through the trouble of building mulch beds and have a good source of manure, I'd look in to hotbeds. The heat coming from the manure breaking down might help your plants get started. I suppose this totally depends on where you're located, Gilbert.

Justin

Another thing for you to consider! Unless you are absolutely sure of the feed source for the horses producing the manure and whether or not it has been sprayed, you should be very concerned about residual herbicides and might want to bioassay the manure before incorporating it into your beds. For instructions on the bioassay technique, see page 5 of the MT Herbicide Carryover Booklet. In several Podcasts, Paul has discussed the very long term nature of much of the toxic gick out there. Contaminated manure has spoiled many gardens around here.

All the horses I am getting manure from have been fed alfalfa hay. Alfalfa can not withstand the worst of the persistent herbicides, (which are designed to kill everything but grass) so it is something of a safety flag. And yes, I am doing a bioassay on some if it non the less.

It's always prudent to age or preferably compost manures, but 6 months seems a bit extreme. But I don't have animals (except for my daughter's rabbit) so I typically only use green manures and compost.