its hard to tell from the pix turk.. but i'll tell you this much.. the indica's will have wider leaves.. much wider than the leaves of sativa's.. indica's have nice wide fingers of the leaves, and sometimes the fingers tend to be a lil shorter than the long, thin leaves of an indica..
also, as they grow, indica's tend to stay shorter, and more bushier.. sativa's like to grow very tall, with fewer branches and less like a bush.. but, the thing is that alot of ganja's today aren't strictly either indica or sativa, so it can be kinda hard to tell just by looking at them.. most strains out now adays are a mix of both indica's and sativa's,,
if you are talking about a store brand fertilizer, or manure, that is in a bottle, i would say that you can go ahead and use some of it on them.. if there is any directions on the bottle it came in that tells you how much to use, i would only use about 1/4 of what it says on the bottle, and mix it with your water, and feed them with it every other watering.. so you would just water with plain water, water and feed, plain water, water and feed, etc..