That 18-18-21 is what is recommended for tomato plants, but it should work just fine for pot plants during bloom, when in flower, thing is, it's a lot high in nitrogen. Nitrogen is not needed, at least an external supply of it is not required. When in bud stage, it needs more phosphorus, the middle number in the NPK ratio. Years ago we used 10-52-10, before all of these fandango nutrients from this company and that company, you know, "My formula 3-47-33 is the best by far, make your plants grow like trees..." "No, don't be fooled, my 4-45-37 is by far the best...bla-bla-bla..." Sure, they know their stuff, but they also like making money...and we all know that by the prices of the stuff. If you want to save money in nutrients, get a bottle of 10-52-10...it used to be 10-54-10, but they changed it, I think because of extra 2 parts phosphorus...it doesn't seem like much, 2 parts ratio difference, but there must be a good reason. Sorry for the babble on, ya, get yourself some 10-52-10 at any hardware or garden centre. They usually have some, and 500 grams is about $7, lasts quite awhile. It's designed for root production booster and transplant shock, but it seemed to work just fine for my weed and everybody else years ago, in fact in the mid 1990's a friend grew a bunch of skunk-bud plants on an island on a lake and he used 10-52-10...the dope was deadly. Good luck Codee...
