How much cow manure fertilizer should I use in a 12x14 raised vegetable garden that is approximately 5 inches deep? Thank you.
The amount you use depends on the manures aging. Well aged manure can be applied liberally and builds the soils as well as feeds the plants therein. Manure that has not been aged well can be "hot" and burn the roots of many plants until it gets consumed into the soils and over time ages out. A rule of thumb is to use 30 to 40 pounds of well aged cattle manure per 100 square feet. Here is a link to an article for you as well: https://www.gardeningknowhow.com/composting/manures/the-benefits-of-manure-in-your-garden.htm