Hi people, I'm 3 weeks into 18/6 vegging on my first ever grow, 30 fruit spirit plants grown from seed.. When the seeds germinated I put them in rapid rooters, then into a humidity dome until they was around 5/6 inches tall. I then re-potted them into 11 litre pots and placed them in my grow room under two 600watt HPS lights. I'm now 3 weeks into veg and some of my plants are measuring up to 22 inches tall.!!! Do you think that is too tall for 3 weeks into vegging..??? And how do you tell if your plants have stretched..??? SO............ Do I change the light cycle to 12/12 or wait a little longer..???? PLEASE HELP...!!!!!!!