How far to put Light?

[kmlzbmr]

Hi this is my first grow in a 4x4 tent with a 350-400W LED I'm growing Ice Wreck and Sour Diesel. The 2 ice wreck have already sprouted the first 2 leaves i have put them in hydroton the 2 sourD has a inch long root and have also put them in hydroton on top so the root cant be seen by light. I have put the required nutrients for seedlings and the drip is almost on top of the seedlings so the run off hits the tap root. They were both germinated at the same time the IW just grew a lot faster. the lights remained off until last nite as i saw leaves...the leaves were still white and down this morning they were pointed up and green now as i left the light on last night about 2.5 feet from the plants.
Few questions:
Should I move the lights closer ?
When do I drain the water and put in fresh water and re-add nutrients?
the sourD root is visible if I look close but I put rocks on top so it casts a dark shadow on the roots, should I completely cover the roots will the plant grow threw?

[DarkLotus760]

Hi kmlzbmr,
Welcome as for your post check this link out https://forum.howtogrowmarijuana.com/...3585-nutrients and read a few of the post and the links they post they might help if not you can troll through the forums and look around you will find what you most likely need.

[Katzie_Wolf71]

I would try about 18 inches with that strong of a LED light and see how she reacts.

[Katzie_Wolf71]

I would try for about 18 inches and see how she reacts to that and take it from there.

[Schmokin]

Hi there. Keep the light backed off until she establishes herself properly. They are still very fragile at this early stage.
Not really sure what you mean about seeing the root, but you should make sure that no light gets to the root at all. You want the roots to be in complete darkness.

[Katzie_Wolf71]

I read this at a site thought it would help.

LED grow lights of different power ratings will perform best at different distances. A 240w LED grow lightshould be 16-30 inches from the top of the canopy. Larger lights such as the 450w LED grow light should be lowered around 20-30 inches from the top of the canopy. More intense lights such as the 600w LED Grow Light shold be kept at 24-26 inhes & the 900w LED Grow Light should be kept 26-42 inches from the top of the canopy of your plants.

Since LEDs do not emit great amount of heat like MH/HPS systems, you can better regulate the room temperature and the temperature immediately below your light. Ambient room temperature can be 82 degrees instead of 72 degrees during lighting and can go as low as 60-65 degrees when the lights are out. Be sure to use less water than you would normally use as LED lights emit much less heat than conventional methods. Wait until your soil is a little bit dry before watering again. You should also use 30% less nutrients as compared with MH/HPS when growing with LEDs