CREATING VS. CONSUMING
A great deal of fuss is made of the role of earthworms in "building rich soil" through their castings. As is well known to scientists, but apparently not to organocultists, earthworms are incapable of surviving unless the soil is rich. Unless fertility, texture, structure and organic content of a soil are to the liking of worms, they will not live and breed there, or remain there if they are introduced artificially. This may come as a shock to those who have spent good money for worms in an effort to build up poor soils.
Equally true is that earthworms are far from being the powerful allies promised in extravagant advertising. Earthworms have no mechanism for creating plant foods, for capturing solar energy or for fixing nitrogen from the atmosphere.
To some small degree, earthworms may make available some deeply-buried fertility that would not be available to shallow-rooted plants like petunias and alyssum. Most plants, however, even lawn grasses, are capable of sending their roots as deep into the soils as earthworms normally burrow.
In the process of living, the earthworm uses up or degrades energy instead of creating it. For this reason, the worm makes the soil poorer rather than richer by the amount of energy it has burned up and passed off as carbon dioxide. Even when the worm dies and its body returns to the soil to increase organic content, that contribution is reduced by the amount of energy the worm used during its life.
Worms redistribute richness rather than create new food elements. In relatively poor soils, but rich enough to keep earthworms alive, the grass may seem greener in spots where castings are heaviest. This comes from the very small amount of nitrogen excreted in the castings. Similar effects can be observed when earthworm "manure" is used on poor soils.
THE PRICE YOU PAY
The "richness" of earthworm castings is a myth so ridiculous that it is difficult to understand how it ever got started. It is clear that before making such claims, the sellers never took the trouble to chemically analyze the castings for nitrogen. I have done so: I purchased a $1 package weighing eight ounces and had it checked by an independent testing laboratory. The nitrogen content was determined as 5/l,000ths of an ounce of actual nitrogen. At that rate, nitrogen would cost $200 an ounce. With nitrogen at about 70 cent a pound from commercial sources, this seems like a terrible price to pay just to keep a myth alive.