Worm Compost Nutrient Analysis

Worm compost typically contains castings, the "poop" of compost worms, residual bits of their bedding and food, and helpful microbes. Botanists have studied the compost to see how it compares to topsoil, commercial plant media and regular compost

  1. Features

    • Worm castings contain five times the available nitrogen, seven times the available potash, and one-and-one-half times more calcium than is found in good topsoil, according to Cortney Timmons' review of the literature.

    Comparison

    • Compared to a commercial plant-growth medium containing inorganic nutrients, worm castings contain more minerals with the exception of magnesium, according to Clive Edwards Jr. and P.J. Bohlen in "Biology and Ecology of Earthworms."

    Properties

    • Compared to garden compost, worm compost contains more than five times the nitrate, nitrogen, as well as more phosphorus, potassium, calcium, zinc, copper and manganese, according to George W. Dickerson of New Mexico State University.

    Significance

    • Researchers note that many of the nutrients in organic waste--including nitrogen, potassium, phosphorus, calcium and magnesium--when processed by earthworms, are changed into forms more readily taken up by plants.

    Considerations

    • Although plants prefer an acidic growth medium, earthworm castings are usually alkaline. Therefore, Edwards and Burrows recommend mixing castings with an acidic medium such as peat.