Cottonseed meal is frequently used for fertilizing acid-loving plants such as azaleas, camellias, and rhododendrons. Dried blood is a byproduct from beef processors. As blood is drained from recently killed animals, it is dried and ground into a powder. It is a rich source of nitrogen and supplies certain essential trace elements including iron. The gardener must be careful not to use more than the amount recommended on the label.
Fish emulsion is a partially decomposed blend of finely pulverized fish.
The odor is intense, but dissipates within a day or two. Fish emulsion contains up to 5 percent readily available nitrogen and is a source of several trace elements. Contrary to popular belief, too strong a solution of fish emulsion can burn plants, particularly those in containers. Animal manure is also a complete fertilizer but is low in nutrients. Manures vary in nutrient content according to the animal source and what the animal has been eating.