Again another person running autos outside, they are ment to be grown indoors, they hate stress and are not hardy like photoperiod strains, think of the sun a a giant full spec light, this light has red and ir in it, this can and will cause your autos to flower prematurely and or dwarf out, while possible it is not advisable and though I have seen a few nice autos grown outdoors the majority are small low yield, now let's get to miricle grow, it sucks and is not ment for weed, they put sodium in it ie salt, try botanacare pro grow autoflowers luv it, allso I suggest you use
FFOF for your medium and don't forget to add a bit of perlite and clay pebbles for good drainage, do not Transplant sow seed in nursery pot you intend to do your whole grow in large autos go in 3gal pots while smallish strains go in 2gal pots.