Some Beginner questions

Questions from a fellow grower:

Got white widow seeds. Any special care for these ladies ?

I have a 8ft by 7ft by 7ft high room.
How many ladies will this accommodate?
How much light ? only have 4 110 outlets in the room.
Exhaust system to damp the odor ?

Some factors to concider here what kind of lights will you be using, are the 4 outlets on the same breaker because this will greatly limit your options? Have you grown before? or is this your first will you be trying to grow hydro, soil soiless?
The room can comfortably fit around 12 plants in 5 gal pots while affording some room to work around your plants depending on lighting a little more or a little less if it is on 2 breakers? It would be easier could run 2 600w veg and 2 1000w flower need exhaust and filter rated for around 160 cfm 2 fans for air movement in room.
things to consider a light draws 5.5-9.3amps 2 600w can be on 1 breaker with 1 house fan 1 1000w can be on 1 breaker with 2 house fans or an exhaust fan. You also have to plan for incidentals like a humidifier or dehumidifier.

Thanks Donald !
Very helpfull. Will check breakers.
Thinking of using the cfl lights. Do You need one for each plant or 1 for 3 ? or is it 1 light per so many sq.ft of growing space ? Planing on 6 to 8 plants.

there is a formula usual math is around 45-60 actual watts (not compared watts) per sqft so a 1000w growlight is good for 3x3 but can be used 4x4. When thinking lighting think actual watts would take almost 50 cfls to equal 1 1000w hps/mh and you would have far less lumens half of a 1000w hps meaning less cannopy penetration.

The industry standard for High Intensity Discharge or HID lights is 50 watts per square foot. Or about 500 watts per square meter.

Roughly, 40-45 watts per square foot for T5 high output or CFL fluorescent lights, and this is mostly as you can bring the light a lot closer to the plants without burning them, and the intensity of light geometrically increases with proximity due to the inverse square law of radiation.

But watt for watt is is hard to get the intensity that HID lights provide.

LEDs and certain other lights can maybe do as little as 30-35 watts per square foot, maybe. A lot of this depends on how good the light is and how it is used. LEDs can often also be brought closer to the plant’s canopy than you might be able to do with HID.

Keep in mind, although it is rare with most types of lights, as you will often burn them with heat before you make the light too intense, some lights that do not put out much heat, like with certain high output high performance LEDs, or maybe a 1000 watt HID with a very efficient enclosed cooled hood, these can sometimes create a condition known as photo inhibition, also know as light burn or light bleaching.

In general, as @Donaldj has said, 40-60 watts per square foot might not be a bad guide to go by.

happy growing,


Everyone who answered so far is correct, but no one has really explained the electrical issue. Yes in 56 sq. ft. you need 2800 watts of light minimum. You have to look at actual wattage use on LEDs to know the true output. You can use slightly less total wattage with LEDs because they only generate light that is useful to your plants. 1200 watts equal 10 amps. 10 amps is the typical home bedroom line. No way you can light this tent, let alone run everything else. Best safest and most simple is you need an electrician to run two dedicated 20 amp lines to your room and these will handle the lights and your base line can handle everything else.

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Actually @Donaldj did touch on this somewhat:

But what @barbara_chadwick7304 has mentioned, especially if you really intend to light the entire space to max wattage is a good point to keep in mind.

Something else to think about, is you can greatly increase a light’s footprint coverage with a light mover.


I was basing my math on standard indoor wiring code in Canada 15 amp minimum breakers and my super rusty electrical aprenticeship.
I certainly should’ve mentioned the light mover as I use one in my veg room turned it off other day since less effective with my 400w running but in general they add roughly 30% to your grow space since anything at outer edge gets less light but if you rotate plants from inside out it works quite well.