Distance from Light to Plant

Some of my plants are looking weird I have been trying to eliminate different possibilities. I have my light (400W HPS) about 3 feet from my plants. I just want to make sure this isnt too hot? it dont feel that hot?

3 feet is real far away from the plants even if they are seedlings with a 400w hps u should be able to keep the light at least 12" away from the top...3 feet away will just cause some serious streching and the light isnt getting all lummens output into your plants....
A simple method of testing for temperature is to use the back of your hand; if its too hot for your hand, its too hot for your plants. Good ventilation is the key to getting your light closer to the garden.

i have some seedlings under some CFL's how far should the lights be away from the top of my lil babies?

crickitmd said:

i have some seedlings under some CFL's how far should the lights be away from the top of my lil babies?

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No further then 2"...check my pics i think they´re even closer maybe an inch or so

I use 400's and I have mine about 10-12" above the tops of the plants. A good rule to check your plants is to place a hand over the tops. If it burns your hands it'll burn the plants, so lower the light until your hand can feel the burn, then heighten them again till you can't feel it. Usually with 400w Hps, this will be about 10-12".

At the moment your plants are having to stretch towards the light, don't worry I made the same mistake on my grow. My plants stretched so much they fell over. Luckily this site was on hand to save my crop. As soon as I positioned the lights correctly the plants stood right up again. Hardy little sods.

Yea mine didnt get to the point they fell over so thats good. I have the light much closer now and they seem to be lovin it.

A 400 watter has a depth of 22-24" , if your using a a reflector with tempered glass and fan I can keep my tops about 6" away, many times I get up to 3" of growth aday and they grow into light

Best way to judge is put the back of your hand under your light and feel the heat, draw away until the you can hold it there without feeling any discomfort. At 21" away are you getting stretching?

I have one of those $45 tower fans blowing on the light and plants and at about 12 inch. It feels warm on my hand not hot

If you get one fan for the tops of the plants and one aimed just below the lights so it is essentailly blowing the heat away. You can bring the lights even lower. I learned this off widow. it is also a good way of keeping your plants shorter. I've got mostly short plants at just over 2 1/2 foot half way through flower, but I've also got a couple that are well over 3 ft, a product of the stretching I was talking about earlier.

Fact is, if it's comfy for the hand, it's comfy for the plants.

I like to use an oscillating fan at stem level on my plants, and rotate the plants themselves every couple of days. In addition to cooling, the gentle breeze in changing directions helps to build a thicker, stronger stem.

Does it matter if the fan is at stem level? i aimed mine in between the lights and top of plants but it's a big 12" fan and it's been on full blast since second week of veg. I also turn the plants only I do it every day. Blowing the tops of the plants also encourages thicker stem growth and helps keep the heat off. My fan is more like a gale force wind at the mo', just over 4 weeks into flower.

I have 6 plants going with only one fan on them and th elights. But it seems to be doing the job for now. Some of my leaves are like a light greem color and some of my leaves look more wrinkled or whilted or something idk what is this? Damn I need some pix for you guys.

EllisD; how long they been in veg'? Have you over-watered? It's better to water less frequently as this gives the soil time to dry out and oxygen get to the roots.

If the leaves are drooping downwards they may need watering. What size pots you using? How regular do you water?

eLLisD said:

I have 6 plants going with only one fan on them and th elights. But it seems to be doing the job for now. Some of my leaves are like a light greem color and some of my leaves look more wrinkled or whilted or something idk what is this? Damn I need some pix for you guys.

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Is the light green at the top or the bottom of the plant? Are the veins in the leaves remaining darker a green? I was thinking it may be a mg def.

Whilted leaves can be caused by both under and over watering. Over watering being the main cause by new growers.

Well I watered yesterday and then my one healthiest looking plant started to droop. When I turn the leaves over and look the veins look healthy also.

skunkushybrid said:

EllisD; how long they been in veg'? Have you over-watered? It's better to water less frequently as this gives the soil time to dry out and oxygen get to the roots.

If the leaves are drooping downwards they may need watering. What size pots you using? How regular do you water?

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They are in 1 gal buckets right now. Im just afraid of not doing something too much... or doing that something too much.

I water them when I THINK they need it. I stick my finger down in the soil and pulled it back out and hardly no dirt remained on my finger so I figured they could use a good watering.