Tops are burning.

I can't adjust the light any higher. I am using an aeroponic system and I have 12 females and they're all too tall. I am using a 432 watt four foot eight light ho t5 system. The plants are almost three feet each and the light can't go any higher. I cropped the plants a little bit because the tops were burning. What do I do? I keep bending and pinching and cropping and they keep rising. It's the second week into budding. The thing to remember is that the light can't go any higher. Can I crop the plants or is it going to reduce the yield?

i always use Bushmaster on the first day of flower and it controlls your stretch...not sure if you can find any quick enough to apply for this run but i would definetly get some for future runs then folllow the hydro instructions on it and it (for aeroponic) will put your plants into flower faster and your plant will only stretch a 1/3 of its normall tenedencies:thumbsup:

will also increase yields:jointsmile:

you can always bend and tie down the plants so your canopy height is lower. even a few inches can be helpful since it's just your tops burning.

I have one plant in dirt unnafected by the light since its a little to the side but yeah I keep bending them down and I'm going to try to tie them down with strings.

I.m using the same light as yours, 8 bulb 4' T5 HO; how high should the lamp be during veg and then flower?

When I grow with T5's I keep my plants an inch or so away. I do not let the plants get to tall because T5's have a hard time penetrating anything more than 6 or so inches away. In my experience I would get colas a few inches long and the rest of the plant would be like popcorn. In my opinion a 3 foot plant is a bit big for T5's.
edit: for your next grow I would build a screen the size of your T5 fixture and do a scrog grow.
this is all my opinion other people might not agree.

I would mabey try scroging the plants. Some how tie a plastic net, chicken wire something like that, about a foot below your light verticly so the plant cant get threw them. BUT the plants normal tendancey is to grow toward the light. So the plant will pop up threw the net and all you do is push it back down under the net. Im not sure how big your grow space is but the plants will start to run along the net. You may need to do some thingin inside your plants at some point but not totaly nessisarie and thats later on. You can do that and the plants will still grow, just not up.Keep them on your normal veg lite sycle and when your ready to flower switch to 12-12 lite sched. keep pushing the veg growth down when it rises up threw the net untill you see bud start to form. Dont push that down let it grow UP UP UP (make sure you have enough room between the lite and your screen so your buds dont burn) Eventually all your left with is a forest of little BUDS!!! YES!!!!!! Its worth a try!

Hope all works out!! Good luck! *Growgood*