To stop the stretch a bit you can break the main stem of the plants a bit under the forming colas. Sounds drastic and I guess it is but I did it to a few of mine as last solution and they got stunned for a few days then continiued like nothing had happened but at an angle, a week later I broke them again and made them grow like the letter "Z" almost. Feels like a terrible thing to do and a hanging top cola is no fun to watch but a few days later it just mends and starts aiming for the light again but at an angle.
I did the same thing, five times, five plants. Each one was an accident, I swear....:thumbsup:...I was trying to bend them over. Same results, they just made a U-turn back up towards the light...Go figure? I don't think you can kill white widow...it's a killer weed.