Research conducted by Agricultural Research Service (ARS) scientists David Ingram and Patricia Millner has made it possible for new recommendations in growing compost tea. Composting usually produces enough heat to kill harmful bacteria, but new research has found that adding solubles like soluble kelp, fish hydrolysates, humic acid, rock dust and proprietary nutrient solutions may infact trigger its production.

The Compost Tea Task Force, formed by the National Organic Standards Board. took this research into consideration when framing new guidelines.

"Use of supplemental nutrients and other additives to produce compost tea gives even a few pathogenic bacteria a growth boost, so testing of the final tea before spraying may be necessary to ensure the absence of human pathogens," said Ingram.