There are many different kinds of garden fertilizers available, both organic and inorganic. The most common organic manures for your garden come from chickens, horses or cows. These manures contain all the basic soil nutrients that your garden needs: nitrogen, potassium and phosphorous. If you're lucky enough to live near a farm or have any of these manure-making animals of your own, you have easy access to a naturally nutrient-rich fertilizer for your garden. Manures from different kinds of animals contain differing nutrient levels, however, and you'll have some other factors to consider when choosing and comparing manure fertilizers for your garden.
Compare manure fertilizers based on their nutritional content and effects on the soil pH, while considering what kinds of plants you'll grow in your garden. Fresh cattle manure contains 11 percent nitrogen, 4 percent phosphorous and 10 percent potassium (11-4-10), but dried cattle manure is more nutrient-rich overall, 45-45-20. Fresh horse manure has equal parts nitrogen and potassium but lower phosphorous content (13-5-13), while dried hog manure is 45-45-20. Fresh chicken manure is 22-22-10 and dried is 31-31-40.
Decide on what kind of manure fertilizer to use depending on what time of year it is. In the autumn, you can spread fresh manures on your garden spot, allowing it to age during the winter and turning it into the soil at planting time. If you're closer to planting time in the spring, use dried, aged manures. Spread and till the manure into the soil about four weeks prior to planting.
Compare the moisture content of manures. Fresh manures have much higher moisture contents than dried or aged manures. Fresh hog manure has the highest moisture content at 87 percent, followed by fresh cattle manure at 86 percent, fresh horse manure at 80 percent and then fresh chicken manure at 73 percent. Dried hog or cattle manure are only 10 percent and dried chicken manure is 13 percent.
Contrast based on nutrient availability. Most of the common animal manures have a medium nutrient-release rate, such as cattle, horse, hog and sheep manures. Chicken manure is slightly more rapid.