Sustainable Production of Living Organic Container-grown Kitchen Herbs

There is a market for 4-inch container-grown living organic kitchen herbs. Organic container-grown kitchen herbs provide easy access to fresh windowsill herbs that can be cut when needed by homeowner. The objective of this research was to develop an organic production system utilizing a constant water subirrigation system for delivering water and fertilizer for container herb production. The initial experiment compared two seeding rates (10 or 15 seeds/container) and fertilizer source for sweet basil (Ocimum basilicum) and cilantro (Coriandrum sativum) production. Potting substrate was Black Gold, an OMRI certified product, containing worm castings. Fertilizer treatments included water only (where the nutrients were only supplied by the potting substrate), poultry feather meal (12% N) incorporated in the substrate at 7g/L, liquid Daniel’s (3-1-1) and Peter’s fertilizer (20-10-20) in the irrigation water at 100 ppm. Plants were harvested after five weeks and evaluated for plant height, biomass, leaf cover and relative chlorophyll content. Seeding rate did not impact plant quality in cilantro, but basil plants seeded at 15 seeds per container produced greater biomass and overall leaf cover compared to the lower seeding rate. Plants irrigated with water alone produced inferior plants for all measured parameters, while the highest quality plants were observed in the inorganic Peter’s fertilizer treatment. Basil and cilantro plants treated with Daniel’s fertilizer showed statistically higher biomass compared to the water only treatment, but had lower fresh and dry weights compared to the feather meal and Peter’s fertilizer-treated plants. Basil and cilantro plants treated with feather meal or Peter’s fertilizer produced commercial quality plants. Basil plants treated with feather meal or Peter’s fertilizer were comparable for biomass and final leaf cover. However, feather meal-treated cilantro plants showed significantly less biomass compared to the Peter’s fertilized plants. Relative chlorophyll content (measured in SPAD units) indicated that only basil and cilantro plants fertilized with Peter’s liquid fertilizer and incorporated feather meal were being supplied with adequate nutrition. This initial study demonstrated that commercial quality organic basil and cilantro could be produced using a constant water capillary mat irrigation system. Additional studies will compare living herb production in traditional plastic versus alternative biocontainers.