The mainstream press is catching up with what we organic gardeners already know. This article in The New York Times details new research showing that worm castings help plants “grow with more vigor, [making] them more resistant to disease and insects, than those grown with other types of composts and fertilizers.” One of the big reason for this is one we’ve long championed: microbes.
The story quotes Norman Q. Arancon, an assistant professor of horticulture at the University of Hawaii at Hilo, who says that “the earthworm’s digestive process, it turns out, is a really nice incubator for microorganisms.” Here’s the take-away from this part of the story:
. . . these microbes, which multiply rapidly when they are excreted, alter the ecosystem of the soil. Some make nitrogen more available to plant roots, accounting for the increased growth. The high diversity and numbers of microbes outperform those in the soil that cause disease.
Arancon also points out a fact that’s Bible and verse to organic growers: soil that’s seen heavy use of artificial fertilizers and pesticides is deficient in these microbes. This is why compost, which is technically not a fertilizer, is such a valuable amendment. It infuses the soil with microbes which make it easier for plants to use the nitrogen and other nutrients that are already there. And it fights plant disease. (more…)