you might try putting those pots in the shade. the black plastic can get very hot in direct sunlight and overheat the roots. a couple boards placed in strategic locations are all it takes until they're ready to be transplanted...which won't be long in those 1 gal's. about the time they're into alternate branching they'll be showing preflowers and will be rootbound and ready for bigger area...preferably set free in the ground. but if continuing to use the plastic pots, paint em white and/or keep em shaded.