Make sure that they are under the same light time as out doors and harden them off by placing them in a shaded place out doors for a day then the next day set them in the direct sun in the morning for a hour or so then put them back in the shade until late afternoon then set them in the sun again. If they look like that didn't hurt them do it for longer morning afternoon until you can leave them in the sun full time. Mid day sun is what will kill them until they get use to it a shade cloth or sheet would work to protect them too.