Fish emulsion is a partially decomposed blend of finely pulverized fish. No matter how little is used, the odor is intense, but it dissipates within a day or two. Fish emulsion is high in nitrogen and is a source of several trace elements. In late spring, when garden plants have sprouted, an application of fish emulsion followed by a deep watering will boost the plants' early growth spurt. Contrary to popular belief, too strong a solution of fish emulsion can cause plants to burn, particularly containerized plants.
Manure is a complete fertilizer, but low in nutrients.
Manures are best used as soil conditioners instead of nutrient suppliers. Commonly available manures include horse, cow, pig, chicken, and sheep. The actual nutrient content varies widely with the highest concentration found when manures are fresh. As manure is aged, leached, or composted, nutrient content is reduced. Even though fresh manures have the highest amount of nutrients, most gardeners prefer to use composted forms of manure to ensure lower amounts of salts, thereby reducing the chance of burning plants.