New Indoor grower, help on size, ventilation, etc

Hi all I am going to be a new indoor grower & wanted to ask some advice on building a grow room.
I want to eventually run 2 x 1000 watt led lights but will only use one to start as I will only be growing 2 plants initially in soil to test it out & add more every cycle as I become more confident.

A few things I would like advice on before starting the design are

This grow room will be outside

  • Should I build 1 grow room to use both lights in or 2 separate rooms with 1 light in each
  • Internal size dimensions for this amount of light
  • Ventilation
  • How high above the plants should LED lights be positioned
  • Ways to control temperature & humidity
  • Should I insulate the walls
  • Should I make the internal walls silver or paint it a high gloss white

Any additional info would be greatly appreciated as I want to get this right the first time.


These are the lights I am looking at getting

HI and welcome to ILGM! :v:

If you build 2 rooms you can have one as veg and one as flower if you want a constant rotation. Otherwise, it just adds to your venting needs and might not be the right option for you.

I’m thinking somewhere around 4’x5’ or maybe 5’x5’ but that’s assuming actual power draw is 50% of the 1000 equivalent. What is the brand of LED.

I would use a 6" blower with a carbon filter. That will cover you even if you go 5’x5’. Get a speed controller.

LED’s normally start around 36"-40" height and move all the way down to around 18" for flower. Again, the manufacturer will recommend heights and that’s what you should follow.

Insulation depends on where you live. You said outside. Best to keep the room around 75F and within 10 degrees of that during “dark” times.

Silver can actually produce hot spots if it directs light into a beam. FLAT white works best I believe.

I hope that helps and others chime in as well! Good luck!

So the lights are around 300 true watts each if I’m reading it right. That would make 600 total.

I think I’d do a 4’ x 4’ tent at most. That gives you 37 true watts per sq. foot.

That add says 4’x4’ for one light but I’m not convinced that would be ideal, not enough IMO.

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Thanks for the welcome Matthew :+1:t2:
Your comment of one veg + one flower could work well with 1-2 plants in each room & just alternate as each room is harvested. Yes the rooms will be outdoors as I have no space inside for them & outdoor growing isn’t an option with kids, friends, relatives etc visiting seeing the plants.
When temps vary how would it be best to control temp inside the room?
How did you work out the approx 300w per light?

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To cool it down increase fan speed and/or add an A/C if at all possible. To raise it you can use a space heater.

I’m assuming this means ~300w but it doesn’t specifically say watts.

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Cool thanks for the info on heating, cooling & power. Yes I assume they mean watts as well when they mention power.
I sourced the lights from the AliExpress app direct from China considering most of the major players produce all their lights there & I have cross referenced images + info from their websites to what I found on AliExpress & they seem the same.
Do you think this light would be adequate for 2 plants or more ?

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You want 25-50 actual watts per SQ. ft. Personally, I think 40w per SQ. ft. is enough. So, you can calculate from there how many or what size.

It’s better to get a couple smaller ones than one big one, it allows you to spread the light out more.

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hello @Radnelac

Welcome to ILGM

Build two rooms one for vegg and one for flower the two rooms must be light tight meaning no light can get into the flower room when your plants are in 12/12 really no leaks what so ever.
When your finished building paint everything FLAT WHITE ok it reflex far better than any thing else.
I’m going to Message you with a wish list that @Matthew420 posted it’s large



Cheers @garrigan62
After thinking I might just build the one room to start & see how it goes & if all goes well then maybe build another one & do the veg + flower rotation.
Yep no worries of light getting in I will make tight seals everywhere & use nomoregaps in all joins to make sure it’s light tight.
I’ve downloaded the guide available on ILGM & am reading through it as well but wanted some advice from others on here too.

Cheers @Matthew420
How much SQ ft space would you allow per plant ?
What about height also ?
I’d like to grow 2 in a box with enough space around them that I can walk around for inspecting / maintenance. Would I be better off making the box larger than really needed & use more (smaller) lights like you suggested to spread the coverage out more ?

I think something like 2’x2’ per plant. If you scrog or do some other form of LST you can keep them pretty low but you need height for the lights too. 5 foot height maybe? I have 6.5 but I have extra.

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Wow guys that list is extensive, I’m going from outdoor growing (from a few years ago, haven’t done any recently) with using basic fertilisers to an indoor setup that I Want to start basic & slowly add to over time lol :joy: I have a source for a good soil that I have recently grown tomatoes, strawberries & roses in very well which I plan to use for now & possibly looking at doing a hydroponics course to upgrade in the future. Just looking at basic grow for now & maybe try some techniques like scrog, etc later, just want to make sure the setup works properly to start with before I begin to experiment :+1:t2:

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That’s perfect 2’x2’ per plant
Horticultural industry standard for lights is 50 watts per square foot


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@Radnelac Welcome to the ILGM forum!

I know @Matthew420 list is extensive but it covers it from A-Z.

I would read thru the list and if there is something on the list you don’t understand, please ask. Also I forget where they are on the list but most of the problems we see with indoor growing are water pH issues. Make sure a pH meter is one of your first purchases and only use pH water from start to finish and you will be a step ahead of the game!

The second issue we see has to do the soil that growers use. We can make recommendations on that as well, based on where you live and whats available.

Happy Growing!

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The list is kinda long. The idea isn’t that you need it all, as I’m sure you figured out :slight_smile: It’s more to maybe jog your memory if you see something on the list but forgot about it.

Thanks for the help guys.
@bob31 I am actually based in Australia. I will make sure I get a ph/ppm wand for water & will also look at a different media that is more suited instead of normal soil, what would you recommend? Coco fibre or hydro setup? I haven’t done hydro before but it seems YouTube could become my best friend haha.
If hydro what media would you suggest for a beginner? I think I would grow tomatoes as a first attempt to make sure I don’t screw up on good plants.
Sorry it took me so long to reply but I had to wait to post, I was restricted on how many replies I could do on my first day haha.

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After looking around a bit on grow box setups I seem to have settled on something like this, seems simple to build & reasonably cheap to setup plus I have access to most of the materials. What do you guys think ? What sort of systems are you running ? Anyone able to share pics ?
Would still like some advice on grow media for a beginner at hydro, would hydroclay be alright?

@Radnelac sounds good!

I’m a strictly sopil person to this point, so I’m not good for making recommendations. Either @garrigan62 , @MacGyverStoner or @Dumme could probably answer that question:

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Probably would have helped if i attached this image :joy:

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No worries @bob31, what type of soil do you use?