What is guano?

Above: Years of accumulation have created a guano deosit
Guano is the original old-fashioned manure. The word guano originated from the Quichua language of the Inca civilization and means "the droppings of seabirds". It is a misnomer to refer to bat dung as guano. As the word is used today, guano describes both bat and seabird manure. The most famous guano was that used by the Inca. The guano would collect on the rainless islands and coast of Peru. Atmospheric conditions insured a minimal loss of nutrients. There is very little leaching of valuable material, nor is there a considerable loss of nitrogenous matter. For this the Inca would guard and regulate the treasured soil enrichener. Access to the guano deposits were restricted to chosen caretakers. Disrupting the rookeries could result in punishment by death.

Guano had become a very important part of the development of agriculture in these United States. During the peak of the guano age drastic steps were taken to maintain a supply for the U.S. farmer. On August 18, 1856, Congress passed an act to authorize protection to be given to citizens of the United States who may discover guano, under which any citizen of the United States was authorized to take possession of and occupy any unclaimed island, rock or key containing guano. The discoverers of such islands were entitled to exclusive rights to the deposits thereon, but the guano could only be removed for the use of citizens of the United States.

A chemical analysis for guano would only be an approximation of the actual nutritional plant food value. This completely natural material will benefit the plant and soil system without magical ingredients. Variations of nutrients can occur. The variations of nutrients enable growers to pick a guano high in nitrogen of phosphorus or both, as well as various trace elements. By labeling a guano high-nitrogen, it is intended to inform the grower that it should be used for its nitrogen but the guano will also contain phosphorus, potassium and micro-nutrients. Similarly, a high-phosphorus will also have some nitrogen, potassium and micronutrients.

Nutrients in guano are as different as there are a variety of producers, food sources and environmental constraints. Seabirds eat strictly small fish and are not scavengers. Bat guano is available from one source that thrives on fruit, while another source feasts on insects. Guano can be fresh, semi-fossilized or fossilized and will be a factor, among others, on the nutrient content when used. Colors have been associated with the geological terms, but are not a good indication of age. White, yellow and red are the colors for fresh, semi-fossilized and fossilized guano, respectively. The amount of moisture present during the aging process will also contribute to the final nutrient level. All parameters must be examined to say a guano is of good quality.

Guano is provided in the ready to use condition, thoroughly aged to the vintage state of a good natural fertilizer. Guano can be used inside or outdoors for all living plants. Guano supplies fast and slow release nutrients to the biological system. Apply the pure guano in smaller amounts than ordinary barnyard or poultry manure. Applied as a top dressing and worked into the soil or mixed with water and applied, guano will have a dramatic influence. Hydroponic growers, in contrast to normal hydroponics, are finding that guano and water are a natural alternative to chemical solution. Use nitrogen guano for growth, phosphorus guano for budding and all guano for your plants general health and well being. Guano can be blended with top-soil before laying sod or grass and while planting trees and shrubs. Add guano to your container growing mix for a supercharged potting soil.

General application:

Average application of guano is two (2) pounds per 100 sq. ft. of vegetable/flower garden once during the growing season. A liquid guano solution can be applied more often. Mix one (1) cup guano into five (5) gallons of water. About one or two teaspoons of guano per quart. One application of liquid guano every second week will be enough to gauge future applications.

Specific application rates are difficult to quote since this is a natural material. Some plants will use more or less depending on type, soil condition and nutrient demand. Seedlings do not need to receive any guano. Young tender plants do not need much fertilizer, if any is to be used, use only a dilute liquid guano solution.
Ornamental trees and shrubs such as rhododendrons, azaleas, roses and eastern redbud do exceptionally well with an application of guano. When planting trees and shrubs mix 1/2 cup guano into the hole. Use 1/4 cup guano when planting roses. After roses are established, more guano can be used. Roses are heavy feeders and really do good with guano.

All garden vegetables will benefit from the nutrient rich guano. Leafy greens prefer high-nitrogen. Fruiting and budding plants prefer dose of nitrogen and then an application of high-phosphorus guano. High-phosphorus guano can be applied at the same time as the nitrogen grow guano to eliminate one step.
If the plants are growing to much, do not continue nitrogen guano applications near the turning point for fruits/buds, at this time the phosphorous, flowering guano is most appreciated.