I can only tell you how I do autos outside. I put them on a heat mat inside until the sprout, and then they immediately go into their final pot and are put outside in full sun from day one. Just like a seed in nature. This way there is no need to harden them off.
That said, if it's 90ºF I'd keep them in the shade during the heat of the day. 80º I'd let them stay out.
In terms of nutes, starting them on a low dose with the second set of leaves is probably a good idea. You have to ramp nutes up more quickly for autos because of the short veg times.
That said, if it's 90ºF I'd keep them in the shade during the heat of the day. 80º I'd let them stay out.
In terms of nutes, starting them on a low dose with the second set of leaves is probably a good idea. You have to ramp nutes up more quickly for autos because of the short veg times.