Problems from the beginning

Hey guys. I checked a few threads already plus i read a whole marihuana diseases article. The reason im still writing here is because I have problems from the beginning. I planted 3 seeds, 1 of them few days ahead of the other two. The seeds are autoflowers- AutoMazar, Ultraviolet and Northern light auto. Im growing outdoors. For the soil I used mixture of plant soil for garden plants (not weed), some pre-used Plagron Grow Mix and some ordinary soil from our garden. Im growing AM and UV for the second time and the first time i didnt have any problems, maybe because I used brand new Plagron Grow mix. The problem with my plants now is, that their leaves look a bit weird. Some parts look dry (brown or yellow) and some parts look burnt (black, grey). For the night and half a day i put them under a large glass because we have big storms here in Czech republic at night. However, its VERY hot in the day so the leaves could burn from the heat im not sure. I attach some pictures for better image. Could this be a nutrient problem or the heat problem? Please, any suggestion will do, I just dont want to lose the plants thanks in advance

Definitely a burn, soil too hot or covering them with glass....why would you re-use soil?