For seedlings and young plants I dont use any superthrive. After a few weeks I start adding 1 drop superthrive per gallon of water, and I work my way up to 3 -4 drops. I dont know if thats right or not, but it works for me. I have been able to go as high as 10 drops per gallon on larger plants with no adverse reaction whatso ever. I dont reccomend 10 drops per gallon, Im simply saying I have been able to do it.
Its also important to remember that superthrive is not a fertilizer. It is a mixture of vitamins and hormones. It contains vitamin b1, 1-Napthyl acetic acid, with a total of 25% disolved solids (50 compounds of carbon, hydrogen, and oxygen.)
The hormone 1-Naphthyl acetic acid (NAA) does not occur naturally. Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), products containing NAA require registration with the Environmental Protection Agency (EPA) as pesticides. The sale of Superthrive is prohibited in Oklahoma, Minnesota, and Oregon as an unregistered pesticide.
Superthrive was developed in the 40's by Dr. John A. A. Thomson, now 97 years old and still at work. In 2006, he was the first chemist to receive the National Lawn & Garden Marketing & Distribution Association's Lifetime Achievement Award