Wonderful worm compost! (#journal)

Humic substances from vermicompost enhance urban lettuce production

Urban agriculture represents about 20 % of Cuban agriculture. However, organic crop production in urban environments is challenging because of intensive plant nutrient requirements and disease incidence. The authors tested an innovative technology based on plant growth promoters isolated from vermicompost and applied directly to lettuce leaves. They applied liquid humates at 10, 15, or 20 mg C L⁻¹ once at the seedling stage and again 15 days after transplantation. Results show that humates at 15 mg C L⁻¹ shortened by 21 days the lettuce production cycle, allowing early harvesting without changing quality while increasing yields. Humate application also decreased total carbohydrate, increased protein, increased nitrate uptake, and stimulated enzyme production in lettuce leaves.