Light meters ???

Could anyone give me any insight on who makes a good light meter? I'm interested in one becuase in my current grow (1000w MH; 4 x 4 tent) putting the light @ 2 feet from the top seems too close. Now I have my light 4 feet from the top and they are now reaching for light; they weren't before.

I feel as though if they are reaching then this is better but i want to maximize my use of the light but don't know how close i should go. Can a light meter give me some help? From what i understand lumens decrease 50% for every 1 foot away from the top of the plant.

my plants are relatively young and am seeing growth but not sure how close they should be and how to gauge how much i can lower it as time passes on.

any suggestions on using a light meter to help? which brand is good?

http://www.littlegreenhouse.com/guide3.shtml

Scroll down a bit. Also us the hand method. If you can't hold the back of your hand under it for a bit of time without discomfort, then your plants won't like it either.

this is a great resource! thanks Grumpy! so my 4' range is on target then....why do i keep hearing this 2' deal? no wonder my plants were reaching; too much light

I agree if you cant hold your hand right above your plants for 1 minute becuase it burns then its also buring your plants.

Yeah I just do the hand to light to top of plant thing....and wherever that is, is where i leave the light positioned...whether it is 4 feet or 2, or 1.5... I can guesstimate that my light it probably somewhere between 2 and 3 feet away...

dante76 said:

this is a great resource! thanks Grumpy! so my 4' range is on target then....why do i keep hearing this 2' deal? no wonder my plants were reaching; too much light

Click to expand...

This doesn't make any sense. Your plants are stretching when the light is at 24" so you put it at 48"? That doens't make any sense now does it? I've never heard of plants stretching due to excessive light. Bleaching and/or burning? Yes. Streching? Eh, not so much. I think you have this backward a bit.

maybe i miswrote something previously. they aren't stretching...at 2' away the leaves stayed down as if they were wilting but i could not say it was too hot (< 83F).

When i rose the light up, it seemed to like that better because the leaves are now up. They are still quite young so that could have been part of the problem. They were put under the 1000mh after two weeks under 2 - 24w HO Florescents.

As they mature and develop more roots, i think i'll be able to lower the light some.

thanks to everyone who commented

That makes WAY more sense. You just meant "reaching" as in the leaves seem to be perked up. I'd say that 2 week old plants would much prefer your light closer to 4'. Even then, you'll have to gradually lower the light, little seedlings don't like to be put on blast with a 1000w light.