Ok say I'm using tiger bloom by fox farms or miracle grow, it doesn't mater the question is if I'm fertilizing from top wit a pail, let's say 3 yr old trees, how much if mixed according to instructions say 1 tablespoon per gallon, how much of that gallon per tree? So should I get 1 tree with a gallon or 5 trees with a gallon, I've been mixing in a 2 gallon pail per institutions and I'll do 4 trees with the 2 gallon container does that sound right? Cause I really have no idea

The concentration of 1 tsp per gallon is the recommended dose I assume? If so just water your plant like you normally would. Giving it more or less water isnt going to change how much ferts it get. If it looks like your plants are hungry than up the amount of fert per gallon. by maybe 25%.

1/2 gallon for a 3 yr old tree doesnt seem like very much. Some of my rooted this year trees are doing 2 gallons a day.