The Use of Cow Manure for Fertilizer
Use fresh cow manure as fertilizer and you might get a stinky garden and grass popping up in your flower beds. But use composted cow manure and you could have a thriving back yard. Cow manure generally doesn’t have as much available nitrogen as commercial chemical fertilizers, but it makes a fine slow-release fertilizer for use on a range of plants — from rose bushes and flowers to bean plants and squashes.
While it is generally more sloppy and difficult to handle than horse manure when fresh, cow manure can be composted into a relatively nutrient-rich material. Many farms sell or give gardeners cow manure that has been composting for six months or more. It tends to contain fewer seeds and fibers than horse manure.
Cow manure should not be used fresh. First, it needs to rot — turning into a more flexible compost in the process. Fresh cow manure can contain dangerous bacteria, such as E. coli, which are destroyed during the composting process. Aside from that, fresh manure often contains grass and weed seeds that can cause havoc with your prepared beds when spread. Finally, the ammonia in fresh manure can cause strange growth patterns and “burn” delicate plant roots.
Spread around 40 pounds of cow manure per 100 square feet of land, suggests Cornell University Department of Agriculture. Once applied, the fertilizer manure should be worked into the top 6 to 9 inches of the soil to ensure the nutrients mix well with the soil. Well-rotted and composted cow manure can go onto the ground in spring. If you plant to apply fresh manure, do it in the fall — never in the spring or growing season.
Cow manure can be used more directly to fertilize individual plants. A scoop of cow manure inserted into the base of a potting hole for squash or pumpkins, for example, gives them a nutritional boost for growing. You can also use cow manure spread around the base of established plants, particularly in sandy or nutrient-poor soils. This won’t have as immediate an impact as chemical fertilizer, but will provide nutrients over a longer period of time.