Answer

My plants are not growing and the roots are not as white as expected

Poor root growth can be attributed to 3 things: 1, water logging - control by using a more open growing media and reducing irrigation: 2, high fertilizer levels - flood to flush out salts; 3, Disease - send a sample of problem and plants to a laboratory to establish which disease is causing the problem. Pythium and Phytophthora require different control measures compared with Rhizoctonia, Theileviopsis and Fusarium. Filex, Terrazole, Basilex and Octave are all available from Scotts for controlling these diseases.