miracle grow potting soil is great for well established plants and will allow you to neglect fertilizing until the roots have fairly well taken over the pot.
if you are concerned about nute burning younger plants like seedlings or clones then you can always go with the miracle grow seed starting mix ... and the nutrients are much less.
miracle grow fertilizer for tomatoes is also a very nice fertilizer for soil grown mary-jane plants during vegetative growth.
miracle grow is not an ideal medium to grow in get some organic soil at home depot or walmart and add some cow munewer ur self thats the best medium for cheap money that plus watering with nutes like flora series g/h nutes is gonna work real good!
but seriously, i would guess that the folks at miracle grow are going to do a lot better at their mix than i would at mine if i just bought some bag that said 'organic' on it and tossed it up with some manure.
i'm not against amending soil, certainly... i prefer more perlite and vermiculite than you will ever find in miracle grow brand. but the miracle grow seed starting mix (also more expensive) I wouldn't change a thing. its very high in pete and almost impossible to over water... my seedlings took off great in it after i killed half of some other seedlings in some compacted 'MasterGeneric' brand of soil that supposably feeds for 9 months instead of the miracle grow claim of 3 months. I'd say be very wary of thos '9 months no need to feed' soils.
ok if i get this miracle gro starter mix can i use it until veg or until flower? whats the deal with that? or can i put my delicate seedlings in the starter mix and after a month plop them in the miracle gro ?
a 16 oz cup of the m.g. seed starting mix would do pretty well for about a month before needing to be transplanted to a larger regular m.g. soil pot. (say 2-3 gal.) you could probably then go almost another month without ever having applied fertilizer. After than you will need to start fertilizing, even in m.g. soil. Mary just grows to fast to not use up all of the nutes in a pot after a month or two. If you kept your plants small and went into flower almost as soon as the plant was 12" tall in a 5 gal. pot you could conceivably never have to fertilize at all (all the way up through harvest) just using m.g. soil.
or you could grow a 2 lb. scrogged plant in 4 inch clay pellet hydro setup some people got skills like that. i still have little to no hydro experience. soil feels so very safe. i love you, dirt.