Guano Fertilizer One Of Natures Finest

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Photo of Bat cave Looking for a place to hang out
to produce some fertilizer

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Guano Fertilizer

Guano is derived from natural deposits of feces and urine from seabirds, bats, and seals collected from areas where favorable climatic conditions insured a minimal loss of nutrients through leaching. Either from seabirds in coastal areas with minimal rainfall, or in the case of bats, from inside caves where climate has little or no effect on the guano deposit, it is one of the finest natural fertilizers available for vegetable gardeners on the market today.


Guano contributes more than its share of nutrients to the soil. Both the bat and seabird guano are an exceptionally rich source of natural nutrients that supplies many beneficial enzymes and bacteria, large amounts of minor and trace minerals as well as being high in nitrogen and phosphorus.

Typical NPK Analysis Of Guano Fertilizers
Guano Bat high Nitrogen1031
Guano Bat high Phosphate3101
Guano Seabird high Nitrogen1281
Guano Seabird high Phosphate1101

Guano can vary greatly in the levels of N.P.K. and trace minerals and is dependent on many factors including, environment, mineral composition of the land or cave of the deposit, food source of the animal and age of the guano deposit. There are many products on the market from a number of regions around the world giving the gardener a choice of products that will suit most needs.

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In addition to everything else, bat droppings go through a process of natural decomposition aided by guano beetles and decomposing microbes, which help control many soil-borne diseases. These microbes help to break down any toxins in the soil and act as a natural fungicide when it is fed to plants via their leaves. It is also effective against rootknot nematodes.

The end result is a natural organic fertilizer that improves the natural balance of the soil, building and conditioner the texture and friability of it without increasing either salt content or acidity.

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Fertilizer Form

Guano usually comes to the gardener in the forms of powder, pellets or liquid. It can be applied in solid form in potting mixes or as a top dressing in the garden and worked into the soil, it can be dissolved in water to make a tea and applied as a foliar spray or injected into an irrigation system. Guano supplies both fast and slow release nutrients to the soil biological system.

Photo of guano fertilizer powder

Photo left - As with all natural manures guano will need time to break down the nutrients into the soluble inorganic form needed for plants. Although guano fertilizer is one of the fastest manure to breakdown the amount of micro bacteria in your soil will have a bearing on the time this takes. Pure guano is applied in much smaller amounts than ordinary barnyard or poultry manure.
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Application rates will vary depending on the type of guano fertilizer and where it is to be used, below are some rough guide lines.

Liquid - Guano Tea

While many nutrient tea easily release their nutrients when brewed guano is reluctant to do so and is better utilized as sidedressing or incorporating into the soil at planting time. However a tea brewed from guano is still valuable for the unique beneficial organisms that are stimulated with aeration brewing and have a positive inpact on the soil bacteria when used as a soil drench.

Solid - Seedling Potting Mixes

While seedlings do not need much fertilizer guano is a good choice for adding to growing mixes. Mix 1-2 heaped tablespoons per one gallon of potting soil, mix thoroughly and water well.

Solid - Garden

All garden vegetables will benefit from the nutrient rich guano. Leafy greens prefer high-nitrogen for growth, as the plant approaches budding and fruiting time the phosphorous, flowering guano, is more appropriate.

Average application of guano is 2 - 3 pounds per 100 sq. ft. of vegetable garden, preferably broadcast before planting. Till or dig the soil to a depth of 4 to 8 inches (10-20 cm) and water well.

For large transplants dig a hole 2-3 times larger than the root ball. Mix into the soil 1 - 3 heaped Tablespoons of guano fertilizer per vegetable transplant, depending on size, and water well.

For established Plants, side dress anytime during the growing season. The amount will depend greatly on the type of vegetable and guano being used, work into the soil gently and water well.


Because of the various choices of NPK content in guano fertilizer it can be used as a natural alternative to chemical solution for growing hydroponically.

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