Determining HID size/wattage for g/room...

Discussion in 'Getting Started 101' started by TheApprentice, Mar 31, 2007.

  1. TheApprentice

    TheApprentice Retired.

    How to determine the correct HID size/wattage for your space.

    I recently asked a question about how many plants i could grow under my 400w hps and my 600w hps,Bud-G assured me i could manage 8 MAXIMUM under 400w hps in the space i had but it got me interested and i know some other members would like to better understand the way it al works so iv been scouring the net and MJ forums in particular,i read this excellent info and i thought it would make excellent informaion to the new growers here at GK as i keep hearing members talk bout using 1000w hps in small areas and i just think,"whats the point?when a 400 or 600 will serve you just as good know what i mean?".SAFE PEEPS:thumbsup:

    "Your grow area is the plants environment,it may not be its natural enviroment but thats why we try so hard and spend so much moeny on trying to simulate the MJ plants natural conditions as much as possible. and we all want the best for our plants. We all want those big, fat, nasty buds that we see online and drool over. When it comes to determining how much wattage your space can handle there are a couple things to consider.

    How big your space is will have a direct effect on how much wattage you can run in there.With HID lights whether HPS or MH, it's important to note that the smaller the space, the more the heat build up. So the other factor would def be heat.

    Ventilating your space properly is key to successfully maintaining temps when using an HID light to grow your own cannabis.As with anything, you get what you put into it. So be sure to properly ventilate your space.

    The charts below should help with determing light size in proportion to room size.I believe they may be slightly different and that's good, as people have differing views on what wattage is best for what space. All charts should be looked at as another guide in your decision on what wattage will be best for you and your plants."

    This chart[1] is not the absolute say in what size can fit in where. With the use of cool tubes, or vented light hoods one can fit a higher wattage lamp into a smaller space. On the flip side also remember that a grow area that is not adequately vented couldn't possibly run the wattage reccomended in this chart.This thread is based on the assumption that your room is properly ventilated.

    Another thing to remember is that the distance of your light from light to plants will effect coverage area. It will also have an effect on how intense the light is that's reaching the plants. Just remember, keeping the lights as low as possible increases your light penetration and increases bud weight. Just be careful not to burn the plants.

    This next chart[~2] will enlighten you on how light intensity is affected due to distance from plants.

    "Please remember that these charts are just a guide to help you choose wisely. Remember if you overshoot and can't vent the heat, then your plants will suffer, and if you undershoot your yeild could suffer. Having a properly ventilated space will help you achieve the best results with your HID light, so keep that in mind."LATERS:pimp:

    Edit: The general idea is to have around 50 watts per square foot of HID lighting.

    Note; This is assuming you have proper ventilation or adequate cooling for your room size.

    Example, if you have a 4x4 room, you should be shooting for 800w of HID lighting LiDiagramA.jpg


    Last edited by a moderator: May 16, 2013

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