IS IT POSSIBLE TO PRODUCE HEALTHY ORGANIC HERBAL PLUG SEEDLINGS THROUGH DIFFERENT PROPORTIONS OF ORGANIC MATERIALS?

Producing healthy herbal plug seedlings is a challenge among organic growers. Most of the organic nutrition studies were done on finish crops in greenhouse or field planting. There is an urgent need to produce organic plugs or seedlings. Establishing uniform healthy plug seedlings is critical for early start in field plantings. The general time frame to produce plugs ranges from 5 to 6 weeks depending on species. Most of the recommended organic substrate or fertilizers do not contain complete elemental nutrients for seedling establishment. Plugs are sensitive to environmental factors from sowing to transplant. They are sensitive to pH, EC, substrate buffer, N form and concentration. Therefore, the study was conducted to investigate the effect of different types of organic substrates suitable for plug production. Two experiments were conducted. The treatments consisted of peat, perlite, coir, feather, blood meal, soy meal and/or compost. They were mixed at different proportions to provide all the macro and micronutrients. Herbal plants, basil, coriander, and rosemary, were grown in a polycarbonate greenhouse. Germination percentage of all the treatments, including the one amended with 40% compost, was above 97% in basil and 91% in coriander. On the whole, coir substrate amended with 20% – 40% compost in basil and 10% – 20% compost in coriander produced better transplants. The shoot and root fresh weights of organic seedlings were greater than the conventionally grown seedlings. The organic rosemary cuttings' root zone pH was 6.7 to 7.3 and EC was 1.3 to 1.8 S.m^-1, in both coir and peatlite amendments. Rooting performance of rosemary cuttings grown in coir amended with soy meal was as good as the conventionally grown cuttings. Cuttings planted in coir amended with feather and blood meal rooted better than the cuttings planted in peatlite amended with soy meal, feather or blood meal.