Having horses is a joy, but one issue is always at hand--what to do with the large amount of manure they produce. Horse manure is a valuable source of nutrients for the garden. Although is can be used in the garden, doing so without the right preparation will cause more problems than it will solve.
Composting horse manure is required before using it as a mulch in the garden. Composting is a method of controlling the decomposition of materials in a bin. Microorganisms and bacteria present in the composting pile reduce horse manure into smaller, nutrient-rich particles that are used in the garden.
Composting breaks down horse manure into a user-friendly material. Collecting and composting horse manure for use as mulch reduces the chances of your horses getting infected by worms and disease in the manure, reduces flies and smell, and reduces the size of the manure pile by 50 percent, says the Pierce County Conservation District. Composting manure also reduces phosphorous and nitrogen runoff from the manure on your property, which may contaminate nearby waters.
A pile is made in a container or in an open pile. Rough material like brush is placed at the bottom of the pile to give it air. Organic material, such as leaves and cut grass, forms the second layer. On top is your layer of manure, then a layer of soil to finish off the pile. The pile is watered till moist, then allowed to sit. The pile will heat up in a few days and begin to sink in the middle.
Horse manure takes several months to completely compost. The pile will heat to 170 degrees Fahrenheit, then drop to 100 degrees in a few weeks' time. Composting will require curing for several weeks after the temperature has dropped, says Washington State University. The material in the pile will be brown and crumbly and have an earthy smell.
Using As Mulch
Manure is suitable for spreading as mulch after it is composted. Compost is best spread once in the season, between April and September. More than this will change the nutritional balance of the soil and leach salts from the manure into the soil. Spread an even 1/4-inch layer of horse manure compost over an area.