lighting question

hey guys,


Totally new at this so forgive my noobness. My growing area is 10 ft by 7.5 ft. I want to put as many plants in there as possible. I want to let plants go threw full growth cycle "no sog". I''d like to use HPS lighting. How many watts will I need to cover that area and how high should the lights be from my babies? Dad tells me metal hallide is better for veg stage is this true? Thanks for any advice. I have choice of bubblegum, ak47, and big bud cuttlings to start with. "my dad rules!!" which would produce biggest yeild and which is easiest for noob?

N3M1515 said:

hey guys,


Totally new at this so forgive my noobness. My growing area is 10 ft by 7.5 ft. I want to put as many plants in there as possible. I want to let plants go threw full growth cycle "no sog". I''d like to use HPS lighting. How many watts will I need to cover that area and how high should the lights be from my babies? Dad tells me metal hallide is better for veg stage is this true? Thanks for any advice. I have choice of bubblegum, ak47, and big bud cuttlings to start with. "my dad rules!!" which would produce biggest yeild and which is easiest for noob?

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you would need more than one. i reckon about four. the wattage all depends probably 400's with plenty of ventilation.

no idea on yield with tho strains.

and yes your dad rules. mine would shop me to the police.

AGSteve said:

you would need more than one. i reckon about four. the wattage all depends probably 400's with plenty of ventilation.

no idea on yield with tho strains.

and yes your dad rules. mine would shop me to the police.

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thanks man if I use 1000 watters how high should I hang lights

N3M1515 said:

thanks man if I use 1000 watters how high should I hang lights

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holy shit if you use 1000w you may only need two. i was thinking you'd be going 250's, 400's at most. rule of thumb is 'if it burns your arm it's to low'. probably roughly a couple of feet. depends if your doing air cooled hoods.

Dad is right, a MH is much better for vegging and an HPS is much better for flowering. The different light spectrums each puts off better fits the different needs of plants during the different stages of growth/life/production.

To avoid the need to buy more lights of different types I would suggest buying lights that can use MH conversion bulbs so you can run MH bulbs for vegging and then HPS bulbs for flowering off the same ballast.

An example of one can be found following the link.

http://www.htgsupply.com/viewproduct.asp?productID=48085


As for area of coverage the information below is roughly what you can expect. With some differences in setups and hoods/reflectors and type and amount of reflective material used the actual area size can vary slightly but what you will find below will pretty much tell you what you need.


Primary light (no natural light) coverages for the different grow light wattages are as follows.

• 100 watt lights: 1.5FT x 1.5FT growing area
• 150/175 watt lights: 2FT x 2FT growing area
• 250 watt lights: 3FT x 3FT growing area
• 400 watt lights: 5FT x 5FT growing area
• 600 watt lights: 6FT x 6FT growing area
• 1000 watt lights: 8FT x 8FT growing area

As for how high off the top of your plants your light will need to be will in part depend on what hood/reflector you go with and what your ventilation system can handle. If you purchase a hood/reflector with a sealed glass panel and vents in both ends where the heated air is drawn out and cooler air replaces it much less heat will be transferred down to your plants so you will then be able to position your light closer to your plants than if you had a hood/reflector that is open and all the heat can and will be transmitted into your grow area.

So how close you can position your lighting will depend on what you purchase and what overall setup you use for both lighting and ventilation.

thanks huge help

Brick Top said:

Primary light (no natural light) coverages for the different grow light wattages are as follows.

• 100 watt lights: 1.5FT x 1.5FT growing area
• 150/175 watt lights: 2FT x 2FT growing area
• 250 watt lights: 3FT x 3FT growing area
• 400 watt lights: 5FT x 5FT growing area
• 600 watt lights: 6FT x 6FT growing area
• 1000 watt lights: 8FT x 8FT growing area

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This chart is bullshit. I suppose if you were growing in shitty soil and not expecting huge growth or yield, this might be ok. It's really probably just an idea of the bare minimum light that would keep a plant growing, but you will never achieve optimum growth at these levels.

If you're growing aero with co2 enrichment, a 1000w will cover 4' x 4' for maximum production while in peak flowering.

N3M1515, if you're looking for full size plants, stick with 1000w lamps. They are the only light that will provide the penetration you need. If you are growing in soil with no CO2, consider using one 1000w lamp for every 30sqft during peak flower.

Invest in the air cooled hood or cool tube. Expect to be around 24" away from the top of the canopy.

You need a seperate area for veg and flower if you plan to harvest every 2-3 months depending on strain. I would split the area in half to do both. A 1000w covers a 5x5 area easily. Id say 6x6 max. Three 600w are better then two 1000w because you can put them closer to the plants so you dont loose as much light penetration. A Mh is best for veg and a HPS is for flower. You can get a dual spectrum bulb to do both but the MH and HPS work better for each job. A 1000w has to be around 20" from the plants without a air cooled hood. Put the back of your hand under the light and see how close you can put it without burning. Thats how close the plants can be. No closer then you can take! Good luck with your growe show.

Bubba Kushman said:

You need a seperate area for veg and flower if you plan to harvest every 2-3 months depending on strain. I would split the area in half to do both. A 1000w covers a 5x5 area easily. Id say 6x6 max. Three 600w are better then two 1000w because you can put them closer to the plants so you dont loose as much light penetration. A Mh is best for veg and a HPS is for flower. You can get a dual spectrum bulb to do both but the MH and HPS work better for each job. A 1000w has to be around 20" from the plants without a air cooled hood. Put the back of your hand under the light and see how close you can put it without burning. Thats how close the plants can be. No closer then you can take! Good luck with your growe show.

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i would also add that you need to leave your hand there for at least a minute. just putting it there for a few seconds won't be accurate.

thanks i'll go with 1000 watters, i'll send pics once i get more up and running