When I clean my chicken coop, I put the manure in a compost bin of its own, add some straw and grass and let it pile up. I started in March and will stop mid-November. When will it be "ready" to add to my raised vegetable beds?
Chicken manure is an excellent soil amendment. I infer that you are cold composting. With this method, it takes longer for compost to mature. If you are continuously adding more manure to the top of your pile, material at the bottom of the pile will be more mature than the material at the top. You might have better results if you cleaned out the coop periodically and compost the manure in discrete batches.
Mammals have separate body openings through which they pass urine and feces; birds have a single opening. Thus, the manure (defined as feces plus urine) has a higher ammonium content than feces alone. Urine leaves the body of any animal as ammonia. Exposed to the air, it soon becomes ammonium.
Ammonium is one of the two forms of nitrogen that plant roots can recognize – the other is nitrate. When applied to the soil, ammonium is transformed into nitrate by soil microbes.
My general rules for amending garden soils with any manures are:
- Apply manure during the growing season or in late summer where you have planted a cover crop.
- Don’t apply manure in the autumn or early spring – nitrogen is highly water-soluble, and supplied at these times of year, the nitrogen is washed below the rooting zone of garden plants.
- Consider which part of the crop you eat. I would apply manure as a side dressing in late spring to fruiting plants like tomatoes or peppers. I would be much more cautious about applying uncomposted manure to leafy greens – especially those like lettuce that are eaten raw.
- Apply manures 2-4 weeks before planting root vegetables. Generally, potatoes, carrots and radishes do not appreciate uncomposted manure.
- Never use raw hog manure and never dog, cat or human manure in vegetable gardens.
Hot composting more rapidly breaks down animal bedding and stabilizes nitrogen as organic matter. Approximately 1 cubic yard of material is required for efficient hot composting.
- One part manure to one part or more of bedding will give the best results.
- Turn and moisten chicken manure and bedding.
- This material should heat up to 130 to 160° F within about 24–36 hours.
- When the temperature has dropped below 110° F, turn again to reheat.
Compost is mature when it does not reheat after moistening and turning. Ideally, you would be unable to recognize any of the composting ingredients. However, the press of the gardening season, and the constant supply of chicken manure may require that you empty out your compost bin before the material is completely broken down.
While tilling compost in remains a common practice, tillage disrupts soil fungal structures and damages soil aggregates. If you are not tilling, you can apply about 1” of compost to the soil surface.
Any weeds germinating from composted chicken manure would be from feed or bedding. It is highly unlikely that seed passing through the gut of a chicken would remain viable.