Depends on what you can get your hands on. You just don't want anything with a lot of nutes in it. It will burn your plants n u can tell if that's happening if your leaf tips start too yellow and brown n die that's the start of nute burn.
Just look at the ingredients on the back of the bags. If it has compost or says it feeds for 2 or 3 months then your prob gunna wana thin it out with the happy frog as much as possible. Preferably you should go too lowes or place like that n buy a bail of peatmoss, couple bags of mirical grow brand perlite, n a bag or 2 of vermiculite. Mix it 50% peat, 40% perlite 10% vermiculite n then mix that ink your happy frog. Will fluff the happy frog up plus add basicly no nutes too the mix so there's no worrys. With a 3cu ft bail of peat. N 4 bags of mg perlite n 1 bag vermiculite u can make around 40 gals of soil for about 35-40 bucks. N then it turns into a lot more wen you add it too the happy frog n mix it up.