Discussion in 'Hydroponics' started by steve.442, Oct 30, 2007.

  1. steve.442

    steve.442 Registered+

    wat is the maximum lumens your plant will make use of, if everything else is optimun, and wat is a good ammount to get big fat solid buds. i give my plants about 40000 as they are 18inch from a 600w sodium. but they have turned a bit yellow directly under the light. not through heat as it is a air cooled hood. also with air con to keep the temp down as it is a small space.
  2. Zcomp

    Zcomp Registered+

    You didn't mention your space size but I can tell you this, After a certain point, CO2 Limits the amount light processing power. If you've reached the lumen ceiling then the only thing to do is add CO2. I don't do it myself but I've read that many places.
  3. steve.442

    steve.442 Registered+

    the reason i am asking is because i read something that said too much light makes your plants turn yellow, and mine are slowly turning yellow. but wat i want to know is wat a good ammount of lumens is.
  4. Opie Yutts

    Opie Yutts Registered+

    Depends on variety, but 1500 to 2000 lumens per square foot is fine for vegging, but up to 3000 can be used by the plant. During flowering, you can do more, like up to 5000 lumens per sq. ft.

    Also, 18 inches even with a sealed hood cold be heat stressing the plants. I know mine did, even though my thermometer said it was only 86 degrees at the canopy height, until I put a small fan in the middle blowing straight up at the light. Now I can get it about a foot from the plants. I don't, because the plants on the edge don't get light that way. Also, when you start getting close to the maximum heat and/or light that your plants can handle, the more perfect your PH and nutrients must be because they have a much greater chance to cause problems.

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