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Thread: Distance from Plant?

  1. #1
    CAPnnCRUNCH is offline Registered+
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    Distance from Plant?

    I'll be using a 4x4 box with 5 plants or so, with a 600w MH, and a 600w HPS, my question is, when I plant my seedlings into my soil, how far away should my light be, and how much closer should i move the light as my plants grow stronger? also when i switch to the HPS for flowering how far away should i keep the light? thanks again any advice I would certainly appreciate it

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    gypski's Avatar
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    I always kept mine at between 14-18 inches. Too close and you will burn them.

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    CAPnnCRUNCH is offline Registered+
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    You kept it at 14-18 inches during all stages at all times? or should you start with them farthr away and gradually get closer?

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    I try to keep my light as close to the plants as the heat will allow. with a closed air cooled hood and exhaust i can keep my light 2 inches away from my canopy level. The further the light is away, the less amount of lumens your plants will get. Test you light at different hieghts and check the temp at your canopy level. 75-85 with outside variances is what i keep mine at.

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    Mustelid's Avatar
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    An inexpensive botanical light meter is a good tool too, you'd be surprised at the different levels of light below the reflector and hood, and you can try to keep any parts of the plant from growing closer then the 5000 foot candle level if you're not using CO2.

    Of course, don't let a plant get that much light without it SLOWLY getting used to it, or growing up towards it.

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    CAPnnCRUNCH is offline Registered+
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    alright cool thanks, oh and one other thing, i was reading on a the lighting system that I am about to purchase that a 600w hps bulb emits 90,000 lumns and that a 600w MH emits somewhere about 60,000 Lms? I heard that each plant should get about 5,000 Lms for optimal growth. Does this mean that I can flower more plants at one time than I can veg at one time? (assuming i'm using the MH to veg, and the HPS to flower)

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    gypski's Avatar
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    Quote Originally Posted by CAPnnCRUNCH View Post
    You kept it at 14-18 inches during all stages at all times? or should you start with them farthr away and gradually get closer?
    I had good succcess at all stages. I had a room temp of 70+ degrees in the 4x8 with a louvered door and fan constantly going as long as the light was on. I burned one at a closer range. It worked for me but to each their own. You will find what works best for you and your plants.

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    gypski's Avatar
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    Quote Originally Posted by CAPnnCRUNCH View Post
    You kept it at 14-18 inches during all stages at all times? or should you start with them farthr away and gradually get closer?
    I had good succcess at all stages. I had a room temp of 70+ degrees in the 4x8 with a louvered door and fan constantly going as long as the light was on. I burned one at a closer range. It worked for me but to each their own. You will find what works best for you and your plants.

    Oh, yeah, I had a 430 HPS sun system then. But, alas, the cops got it and everything else. Had 10 plants and they reported only 7 and trimmed off the leaves before weighing it and sending it to the SP lab for analysis. Nothing like tampering with evidence by some LEOs!!!!

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    Mustelid's Avatar
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    Quote Originally Posted by CAPnnCRUNCH View Post
    alright cool thanks, oh and one other thing, i was reading on a the lighting system that I am about to purchase that a 600w hps bulb emits 90,000 lumns and that a 600w MH emits somewhere about 60,000 Lms? I heard that each plant should get about 5,000 Lms for optimal growth. Does this mean that I can flower more plants at one time than I can veg at one time? (assuming i'm using the MH to veg, and the HPS to flower)
    The 5000 for optimum growth should be foot-candles, which are lumens per square foot.

    Lumens are weighted for sensitivity to the human eye, not for plant photosynthesis, though lumens / foot-candles are a consistent standard to go by, and because flowering plants like the redder portion of the spectrum, the yellow biased lumen measure works well enough there.

    For vegetative growth, try not to over analyze lumens and foot-candles, rather use a light meter as a rough guide, let them slowly get up to 3000-5000 foot candles and figure out how much they can take, and what they like the best so you can best grow the strain that you'll learn to care for.

    Basically, you flower when your plants get to a certain size, assuming that they'll grow twice that height by the end of flower. Different strains and conditions alter this, so you'll have to learn the best time to switch to flowering on your own.

    You should think of a higher amount of vegetative light as speeding up the growth rates, rather then supporting a certain number of plants, so you'll wait less time between those wonderful harvests.

    A 600 watt metal halide conversion bulb sounds like a great way to minimize your vegetative time for a 600 watt HPS flowering.

    Best of luck on your grow!

    Mustelid the Pine Marten.

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