Superthrive can be bought at most gardening shops and in the garden section of Wal-Mart etc.... Superthrive is very potent so make sure you read the bottle etc and pre-mix it with your water...
As far as nutes I feed mine viagro all purpose plant food with a Nitrogen Potas., and Phos. ratio of 10-10-10. Those numbers will be on the bottle.. Tomato plant food has about the same as well. When I began to give nutes for the first few times I put about a teaspoon full mixed in with my 1 gallon water container. Shake it up and if you have a ph meter, make sure and check the water first, but it should be alright if you are using a PH neutral Water, like cheap bottled spring water from the grocery store. I wouldn't use distilled water just in case you are as it is robbed of micro minerals the plant needs in the hydrating process. water it only when it needs it (when the soil is almost dry... usually every few days) Make sure you start out slow with the nutes bro because it could easily be burnt....
Good luck
Elway