At it again(growing) after 30yr lay off. Need all you growing maestros advice!

Hi fellow growers. It’s a completely new game these days. I grew up in AK.,grew hydroponics in pure gravel with vermiculite and perlite mix successfully in winter and summer but now reside in the Indian Nation. Hot and Humid. Many 100 degree days and 80% or higher RH. Grow room is 14’x16’ insulated unfinished bedroom, 1752 cf. I’m thinking start with 2@1000 W. HPS. Lots of heat. My make up air can be up to 105 degrees. How often should the air inside my room be turned over,or do you think a 6"- 442 CFM carbon filtration system is sufficient or should I get an 8"-750 CFM carbon filtration system? Also, how do I cool and or clean up my heavy heated make up air from outside,same way as exhaust system? At this time grow room is unheated and there’s no cooling but is attatched to my house. This is my research stage but plan on mid Feb starting my spring grow with femenised high yield Super Skunk or Amnesia Haze. 12@5G ebb and flow system. Your knowledge is paramount for my success

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A few thoughts…

You will definitely need to air condition that room. A 10,000 BTU window air conditioner should work well in that kind of heat. In average conditions a 5,000 BTU air conditioner would suffice, but I would err on the side of caution in your situation.

Unless you need to grow a lot of plants, consider partitioning that room into something smaller or putting a tent in it. Not only will there be less to cool, but also less to light. Going with the minimum (35 watts per square feet) recommended lighting, you would need 7,840 watts of HID lighting for that space. Going with the optimal (50 watts per square feet) you would need 11,200 watts of light. That’s a lot of money… and heat.

Be sure to use an air cooled reflector with your light. This will significantly reduce the amount of heat from the light being put into your grow space. Instead, it goes right out through your exhaust fan.

Neither of the fans you proposed are enough for that amount of space, either. Someone else can pipe in if there is an optimal air exchange rate, but I believe I have read that it is a minimum of 1 complete exchange per minute. I use a 400 CFM fan for a 100 cubic foot space. You will probably want both intake and exhaust fans - turn the intake fans on when you need a cooling boost. Again, making your grow space smaller will make this easier (and cheaper).

If you are venting to the outside world, you won’t need a carbon filter. This will increase the efficiency of your fans.


Tommy, thanks for a prompt reply. I am a construction guy by trade and do HVAC, electrical and plumbing. I am a remodeler. Knowledgeable. First off, I want to maximize my yield in this room. Knowing thru all you growers, with your experience and knowledge, the minimums and maximums of air exchange, wattage per sq ft for optimal growth is very valuable, then I can either meet the demand or scale down my op. 16’x14’ floor =1792 sq ft. 1792sq ft.x 35W=62,720W.? Is my math screwed up? 1000W light divided by 35W per sq ft = 28.57sq ft. That’s roughly a 7x4 area. Will four air cooled 1000W HPS do the trick with a 1700CFM carbon exhaust. I have to filter my smell cause I am literally 100 yds behind our small town police station. I and my women have medicinal marijuana cards so I can legally grow 12 plants. Mums the word on yield! What’s the pevailing thought on a 1000W footprint on sqare footage? I have grown in a garage 16’x20’ twelve plants under 2@1000 MH lights with 4’ hoods, soak method and yielded about 3oz per plant. I am striving for 8oz plants minimum.

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Tommy, 16’x14’=224 sq ft but is 1792 cubic ft. Two diffferent things between light footprint and air exchange. Ha! My bad.

i was just about to link you in @dbrn32

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HungryBud…What do you mean “Link you in?” Computers aren’t my thing.

I would toss the wattage per square foot out the window and focus on your par levels. Once you get that squared away, see where you’re at for temps. You’re ambient alone will justify cooling. If you’re going hid you can do air cooled hoods to help keep a lot of that heat out of the room. But since you’re gonna need cooling anyway, it may be worth while to look at a sealed setup and supplemental co2.

Standard single ended hps will do 16-20 square feet depending on hood. You can push flowering intensity to 5x5 with a double ended light.

Cool. So me just be preliminary and researching at this time, so I can start purchasing lights, making my own ebb and flow system, purchasing air exchange system, and realizing i am starting in mid winter and it’s 38 degrees outside with 100 % humidity right now but can be 70 degrees and 50% H next week I am going to order 2@1000W HPS, order or make my own 1700 CFM air exchange unit with whatever size diameter flex duct it requires, make a 12 pot ebb and flow system or potentially a drip system, plumb in be ready with a heat source, install a 10000 BTU AC for when and if it’s needed. Where can I purchase reflective sheeting with R Value to help against the outside ambient temp and the direct radiant sun heat, to fit a 12’x16’ room? Tents are darn expensive and I haven’t seen one as big as my room?

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Here’s what I’ve used to insulate and reflect

This is from LOWES

Item # 409814 Model # BP48100

Reflectix 400-sq ft Reflective Roll Insulation (48-in W x 100-ft L)

good info. thanks guys. What fertilizer do you recommend and what ratio nitrogen, potassium, potash,for veg, and bloom?