| Organic systems are rigidly regulated in Canada and specify that no synthetic materials be permitted in growing substrates. Research on organic growing substrates is generally not sufficient enough that practical and dependable use recommendations for organic growers can be made. This thesis is an investigation of organic growing substrates for the production of healthy organic tomato transplants and an investigation of the use of manure compost, alone or in combination with Clonostachys rosea, for the suppression of root disease caused by Pythium ultimum in organic tomato transplants. Several substrate formulations consisting of peat moss, coconut coir, fine perlite, fine vermiculite, manure compost, vermicompost, worm castings, yard waste compost, pine bark compost, and/ or aged pine bark were successful for growing healthy tomato transplants in 10-cm pots with organic fertilizer applications. Transplant roots from sterilized substrates that were inoculated with P. ultimum were more fragile compared to other roots from other treatments, which suggested that some effect on roots was occurring. It was concluded that the establishment of P. ultimum in the root zone of transplants is more likely to occur when the transplants are grown in sterilized substrates that are not amended with the beneficial fungal endophyte C. rosea. |
