i use 250w MH light during vegetative stage, currently my plant height is around 30cm high and it has been growing for about a month old. i've made adjustment with the light altitude whenever my plant gaining height my question is do i need to adjust the light to approximately 2 feet away on top of my plant whenever my plant growing high?
For 250W MH, 12-18" is about the right height. You want it to be as close as possible without scorching your plants. A good way to test this is to take your hand and place it palm down over your plants. If the back of your hand gets hot, then it is too close. If it doesn't, then perhaps you can move it closer. Depending on your ventilation you may be able to have it as close as 8". Good luck.
i've been wondering why the stem was too long between each stage of leaves btw thanks alot man, i appreciate it
I keep a 250w MH 6-8 inches above the top of the plants. The issue isn't distance per se, it's heat. Your goal should be to manage the heat to be able to get the light as close as possible.
I agree with toasty... When i was running my 250 at times i would be within a couple inches, vented of course,,,,