Hi,
Your night temperatures have been too cold,but growing outside theres little you can do other than use a green house ( or something that will give a similar effect) or you could of brought them in overnight.
Also,for autos you don't need to switch to 12/12. Only for photoperiods. The first 3 weeks of flower you should still be using nitrogen but no excessively, by the end of the first 3 weeks you should of cut out all nitrogen and switched to P and K. Start at half or even quarter dose of the recommended and build it up gradually overtime, week by week. Don't over water, just water enough to saturate the medium, and only then re water when the medium is dry, to check its dry poke your finger an inch or two into your growing medium, if dry water.. if not wait until it is. You'll really slow the growth of your plant down by overwatering. It states you have two plants but I only see one, which looks like the auto.
