How far do you put your lights above the plants?

You can have the most air cooled lights on the planet, and it doesn't mean you should keep them hoods as close as possible. A light meter will show you how high to keep your hood. Different hoods have different footprints. But it usually works out to be around 2' above the plant tops, if your 600w is covering 3x3 or your 1000w is covering 4x4.

With multiple lights, cross lighting is more beneficial than close lighting every time. 2-3ft should work fine in your case. I have a 6 and a 1k, the 6 has always been at least 24" and the 1k around 30". These are 21 days in flower and have always had that distance from the lights, I'm not feeling like I need to change anything.

i put my 600w 10" from the tops of the plants my temps stay around 80ish if its hot outside it get to about 90 and my plants love it never sufferd with heat stress get great weed but they use a lot more water i can water when its hot out every 2/3 days

Aeroknow said:

You can have the most air cooled lights on the planet, and it doesn't mean you should keep them hoods as close as possible. A light meter will show you how high to keep your hood. Different hoods have different footprints. But it usually works out to be around 2' above the plant tops, if your 600w is covering 3x3 or your 1000w is covering 4x4.

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You don't need a fancy pansy light meter - stick your head at the canopy if the back of your head can take the heat so can your plants.

My No1 cause of bad grows is complicating shit. KISS

Sandgrouper said:

You don't need a fancy pansy light meter - stick your head at the canopy if the back of your head can take the heat so can your plants.

My No1 cause of bad grows is complicating shit. KISS

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I am a believer in KISS. But a light meter is like 20 bucks?. You can use that "fancy pansy" light meter to check if ur bulbs need replacing to.

Aeroknow said:

I am a believer in KISS. But a light meter is like 20 bucks?. You can use that "fancy pansy" light meter to check if ur bulbs need replacing to.

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Fair point - never looked at the price of them, if that is all they are could be worth throwing one in the draw.

Sandgrouper said:

Fair point - never looked at the price of them, if that is all they are could be worth throwing one in the draw.

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It's worth 20 bucks just to have something new to play with. Start with a new bulb, get a reading from say 30". Now you can check periodically if that bulb, or other bulbs are still good.

Ive always wanted to get a light meter just to play with and see where the numbers stand. Anyone have one they could recommend? Id like to get a cheap one just for fun, who knows, maybe there are some practical uses for them, like ya'll just said, checking your bulbs for intensity and such could help you keep a more efficient and stable intensity. Ive never actually had a bulb burn out on me believe it or not, I seem to replace them annually by trying new spectrum's and new manufactures of bulbs. Ive got all kinds of different used bulbs laying around. I keep them for back-ups.

I found this doesn't really help too much...

I'va had this one for years
http://www.horticulturesource.com/product_info.php?products_id=6368

Thanks Aeroknow, much appreciated!

Aeroknow said:

I am a believer in KISS. But a light meter is like 20 bucks?. You can use that "fancy pansy" light meter to check if ur bulbs need replacing to.

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yep, and an IR thermometer is only about the same.

why use your hand?

When you can know exactly how hot the tops are...or your ballasts....or the outlet on your hoods....or your rez..or infinitely more things in a grow.....for twenty bucks. No brainer

Ninja Mechanics said:

Thanks Aeroknow, much appreciated!

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No prob dude. That little cheap meter can also tell you if the cap on a magnetic ballast is fading to. Sure there are other ways to check them caps, but when you put a new bulb in them older type ballasts, check it with that known measurement you took before, and say wtf man! Chances are its the cap fading. It happens with age/wear/heat. Caps are cheap, lumens are valuable rite? Not saying you rock magnetic ballasts.

That is good to know! You know, honestly I have been tossing around the idea of switching to magnetic from digital. Ive had plenty of digital ballasts take craps on me and there really isn't much you can do about it. Magnetic ballasts have been around for ages and are still used today, makes me wonder why I am still using digital!? Plus like you said, you can maintain a magnetic ballast.