new room

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Honestly if you can't grow 1 plant what chance do you stand with 25? Keep air flowing, keep water moving. Do your homework. I would do a more manageable grow

240 * 5 = 1200w 1200 x 2.5 is 3000 umol/s PAR or a bit less from just an average LED and closer to 3500 with a top-of-the-line efficacy. Efficacy matters.. watts are not a good measure for this. umol/s PAR is and that info should be readily available, otherwise it's a red flag for that manufacturer.... you wouldn't hide that info if they were good specs. Also, light manufacturer's lie a lot, so always compare their specs to how they are tested by the LED diode manufacturer - i.e. samsung or bridgelux etc... anytime they are not powered as they are tested means reduced efficacy and reduced longevity along with increased heat per watt produced (heat = wasted electricity, inefficiency)

Better have a massive dehumidifier. 4m^2, so simply multiply target PPFD by 4 and that's how many umol/s PAR you need from your lights. If you do this shoot for ~40 dli and what hits the plant will be less but about right for atmospheric co2. Autos only need 18h, but if you want to be able to grow photos in future, do the calculations for 12 hour operation. If you don't use 18/6 for autos, make sure you choose the right target PPFD for the DLI you want... multply by 4 for 4m^2 area. photos based on 12/12 needs - 3600 umol/s PAR from lights Autos on 18/6 - 2400 umol/s PAR This does not save electricity. Both will cost the same. You can see the umol/s PAR is inversely proportional to hours of operation, ceterus paribus. This will get you very close to what you want... always have to adjust for local variables as there is not 1 answer for all unless all are adhereing to lab-precise conditions.

nice 😉 Choose pots of no more than 8 liters (preferably clothes pots), and consider one-bud setup or at least solid lollipopping

Sounds spot on to me.. A few fans for circulation inside. Best of luck

That’s a solid plan bro! Five × 240 W full-spectrum will give you great coverage for that space. Just make sure your intake matches closer to your exhaust 300 m³ might be a bit low for 895 m³ out. Keep good air circulation inside and you’ll crush it with those Northern Lights