FFOF can cause Nute burn. Pure FFOF was awsome for my Blueberry grow. For Grapefruit-diesel it was too much. I diluted with peat moss and perlite almost 50-50 to get things going. Even such 50-50 mix is too much for seedlings. They need cooler soil. Also Organics CAN burn your crop, quick too. Whoever says not is out to luuch. Different strains of Marijuana have different affinities for hot soil. Its best to start very weak and condition to hotter soil. In your final transplant have two grades of soil, the hotter under the cooler. Generally......most people have nute burn issues as appose to deficiency issues. Also, In my opinion, flushing does not make nute burn worse, and as soil dries, the concentraation of nutes increases and could result in micronutrient lockup. OVERALL--GO EASY WITH MJ__SHE LIKE IT MILD.