If too dry, it will not compact properly and will be too porous, making irrigation difficult. A mechanized blender is recommended for larger commercial operations where on-site mixing of media is desired. Adding surfactants in the blending process is not recommended without preliminary evaluation. Growers may add lime to the medium to adjust pH to the recommended levels of 5.0 to 5.5. Normally, water-soluble fertilizers are supplied through the irrigation system.
Some growers use about half the recommended rate to maintain more flexibility in fertilization.
This treatment supplies most of the NPK needed, but additional nutrients will he necessary. Incorporating slow-release fertilizers will also reduce the time spent applying nutrients through the irrigation system. Using a well-drained medium and allowing it to dry between irrigation impedes fungus gnat development. Nursery personnel should wear gloves and respirators when mixing this material into the media. Inoculation can be accomplished by incorporating specially produced vegetative mycelium into the growing medium.