Grow Room Height Problem

[nicknack]

Tonight my plants will start their 12/12. However, their height is about 50cm from my 250w bulb.
I don't think it would be good for them get any closer, so what extra height would you expect in the 12/12 period? These are a sativa.

Cheers.

[BudBill]

A sativa can double in height. You can have them pretty close to a 250w. Using the back of your hand a guage try ~ 25 cm (10 inches). You hand should get warm but not real hot. Good airflow will help greatly.

The lumens diminish by the square of the distance so the closer the better.

[nicknack]

Always the bearer of good news BB. I have a 10" fan running over the top so will have a good flow... lets hope they don't grow double though!

[BudBill]

Excellent my man! Keep an eye on the temps and you can always bend and tie the tops down :)

[harvester]

A sativa can triple in height.