Stretching Seedlings

I have just recently put my seedlings from 24 hour flouro to 18/6 HPS. While I was making this conversion I started thinking about what keeps them from stretching to the light since the HPS has to be so much further away because of heat? And also, how long before they can be sexed, one I think is ready, it is about 6 inches tall, and the others are about 4 inches, but with not many leaves, I beleive they have stretched too much while they were under flouro...

when you start by seed you can expect to have plants grow at differnt rates hieghts ect... six inches is about when they start to bush out if the light is on them correctly just above where you feel the burn from the light Plants also have to adjust to differnt types of light so give em a few days and they will start bushing out

Don't worry about sexing your plants for quit some time. The hps is further away but it is also more intense.