My first grow

hey i've been snooping around these forums reading up.. my biggest plant was my brother he was growing outside and i started to take care of it it was in bad condition.. the next 2 smaller ones were accidently grown outside then i took them inside after about a week, then the smallest ones sprouted about 2 days ago, they have purple stems, all the ones that came out that batch did.. i dont know if i did something wrong or if it's the strain

the grow room i purchased yesterday the temp @ 91 is because i just installed, i have since gotten better ventilation and temp stays 78-85