I grow outside under a canopy (about 3 metres high, trees about 6/7 metres high) made of trees I have spent some years developing,one side is Palms and trees the other is almost open apart from a few conifirs.I live in Spain so even under this canopy I get good sun it comes in from the open side and filters thru from above. I guess this must reduce the light just enough to fool my girls to flower early becouse by mid july all mine are sexed and ready to go.I rotate my plants within the canopy cos some get more sun than others. once they are sexed I position them so that some come on quite early,and I have one now that is frostin nicely some just starting to frost and others that are just showing few pistals. they range in size from 5 to over 7 feet. So unless your growing in pure daylight yes you can get some early flowering, good aint it lol.