My vegetable garden is 25' wide and 30' long. The soil is of good quality. How much manure should I use? Also is there any synthetic fertilizer or additives I could use to aid in breaking down the manure to make the nutrients more readily available for the plants? Thank you.
How Much Horse Manure Should I Use?
Certified GKH Gardening Expert
You do not want to use raw horse manure on your garden beds. First, because the seeds in it have not been killed by heat from composting (and will grow) and second because the nitrogen is to "hot" and needs time to mellow. You want to leave it to compost/rot for a few months in a compost bin before you put it on your beds. You may find this article helpful: http://whatcom.wsu.edu/ag/compost/horsecompost.htm
Once it has been composted and the nitrogen has mellowed, you can spread it up to 3-4 inches deep over the ground and then work it in.