moghedian

As per the grow guide:

"What if you want to determine how much light you need in watts? The general rule of thumb for providing light for an area is a minimum of 30 watts per square foot. 50 watts per square foot is optimal. You can determine the proper lighting for your area by using this formula: 50 watts x ?(your) square feet. Example: You have an area of 10 sq. ft. - 50 watts x 10 s.f. = 500 watts/sq. ft. (optimal). Also, remember that fluorescent's are weaker and emit less light than an HID. This means you will need 5 times the amount of wattage to equal the output of an HID."

I have not yet bought my lights, as if I proceed this will be my first indoors grow. Initially I was thinking of running a 600Watt Metal Halide with a 600Watt High Pressure Sodium for my lights in this grow. (i.e. both lights on for the whole grow) However my grow room is 12 feet x 10 feet in area. (An almost square rectangle of 120 square feet). I never intended to fill up the whole room, but I do want to take better advantage of the space I have. I haven't investigated prices of buying the lights and balasts etc yet but I expect my maximum would be something like 2x 1000Watt lights and maybe an additional 600Watt light or something like that.

Say I do buy 3 lights which together draw 2600Watts, does this mean that I would be best advised given the grow guide to grow only so many plants that will happily fit in an area of 52 square feet (i.e. 52 x 50 = 2600) in a circle (or best fitting shape to the light cast) directly beneath the lights, or does this imply I should somehow make false walls inside the room to line with a reflective surface which will form a smaller "room" for the plants to be growing in? (I should point out that I suspect it's the former - but I had to ask)

In short my question is should I simply grow only so many plants as will happily fit in an area directly under the lights equal to 52 square feet if I choose to buy 2x1000watt + 1x600Watt lights, despite the fact that the room is actually larger than 52 square feet? If so the walls and floor of the 12x10 foot room will lined with a reflective surface or painted white.

I hope this is clear and I've given enough information for someone to clarify this for me and I hope it's not to stupid a question.

sumguy

moghedian, there are no stupid questions...only stupid people
-Mr. H. Garrison - Southpark, CO

sorry.. Running a huge grow would be quite an undertaking. Lots of cooling and odor control issues to think about.. If you filled up that whole room...that'd be a big grow. I would go with the 'making flase walls in the room' plan. You may want to use 1 corner of the room and have a 5' x 6' area. Remember, your flowering area must be lightproof so keep that in mind when deciding to build "false walls". They will have to be pretty well built if they are to keep the light out of the area.

How about splitting up your lights and growing area. If you were considering buying 2600 watts worth of light then try this.. You have enough room in that 12x10 area to do alot. You could build 2 seperate areas, 1 for vegging, and 1 for flowering. In the veg box you could run the 1000W MH lamp. Lightproofing this one is not critical. In the flowering box you could run 2 x 600w HPS lamps. Lightproofing this one IS critical. You would not be harvesting as MUCH as if you dedicated the whole area to 1 big grow but you will have a continuous cycle going on so your overall yield would be better.

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sumguy
got better .. growin' good

My Smallscale Growbox Lighting/Ventilation Design | The Grow Guide

moghedian

Thank for your reply, Sumguy; I nearly messed myself laughing at that Mr. Garrison quote. :-)

I'm glad you replied because otherwise I would have gone right on ahead and set up the lights in the centre of the room and just positioned the plants underneath the best I could. As I said a massive yield is not really my objective despite the space available - but at the same time I've got 3 sets of lungs to feed with the crops [all in the family ;-) ]. We don't want to have a continuous grow opperation happening if we can avoid that RE: the continuous cycle of growing, but I do like your ideas about putting in place light proof false walls to create smaller rooms of the appropriate size for the amount of light available.

The weed is not to sell, it's to get me wasted, so my aim is killer bud rather than truck loads of dope. Thanks so much for your reply.

If anyone has further comments or ideas I will check back periodically, as I'm keen to be well informed. :-) Bong on. :-)

skizank

Instead of wattage per square foot, think lumens per square foot. IMO, you want at least 5,000 lumens per square foot. The grow guide suggest 7,000 lumens per square foot. Anything above that and you're set.

Regarding what lights to get, and how much space to use...First figure out how much space you need. You want to use the smallest area possible to get the most from your lighting. How many plants are you growing? How big will they get? Will you be training them at all? All this will affect how much space you need. If the plants will only grow to 3-4 feet and untrained, figure about 2 square feet per plant. Maybe more, maybe less.

Once you figure out the size of the space you want to use, you can then decide what lights to get. You want to try for at least 5,000-7,000 lumens per square foot. Say you decide to build a smaller room 5'x6', or 30 square feet. A 1000w MH gives around 90,000 lumens & a 1000w HPS gives around 140,000 lumens. 230,000 lumens / 30 square feet = 7,666.66 lumens per square foot. That will grow you some nice buds. Or if you go with the 2600w total, maybe a 1000w MH (90,000 lumens), 1000w HPS (140,000 lumens), and a 600w HPS (92,000 lumens), you'd be getting 10,733.33 lumens per square foot. That will grow you some even nicer buds.

Either way, you will have a lot of killer smoke in the end.
Good luck with your grow.
Peace


ps...you're going to need some serious ventilation to control all that heat.

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There's only three ways to do things...The right way, the wrong way, and the way I do it.

2nd indoor grow...600 watts in the closet

moghedian

Thank you so much for your reply Skizank. I agree that the lumens per square foot is the essential factor, not the wattage per square foot, but I'd had such a hard time finding data about how many lumens the different lights produce that the wattage per square foot was my attempt to approximate. I've taken note of the values you gave me for the 1000Watt HPS, 1000Watt MH and 600WattHPS.

I want my babies to have atleast 7000 lumens per square foot as the grow guide suggests, and I will be buying as much lighting as I possibly can afford since I won't be able to afford the amount of lighting my room needs. So instead I will buy as much light as possible and then reduce the size of the room with reflective or white false walls so that with the lights I have will illuminate the room to at atleast 7000 lumens per square foot. Then it will be a matter of placing the buckets that would hold the mature plants, spaced pretty much as you suggested to find how many plants I will be growing. (i.e. the number of plants will depend on the space available in the "false room" and the space available in the "false room" will depend on the amount of light I can afford.)

I've been reading Rock Climbers journals which are absolutely fantastic for me as my set up will have similar lights and I will also be growing in big buckets of soil. It quickly became apparent there that the ventilation will be important, but fortunately plans are already in place to incorporate good ventilation into the room before the grow begins. Another benificial circumstance of my grow is that my grow room is virtually underground and has no windows. It's a cold, dark room. :-)

Thanks again for your reply.