would it be ok to switch from 18hrs of light back to 24hrs? i've had the seedlings for 3 days about in 18hrs of light and been thinking would it be ok to switch back to 24hrs without stressing them?
40 plants is a REALLY bad idea, if you dont have proper ventilation and carbon filters you'll get busted for the smell. And the lights might be a problem. just to add always buy everything in cash.
Nice job with such low lighting!
But as mentioned above you should buy a HPS/MH mix it's rly good for vegging and flowering, but makes alot of heat. people saying get a 400w hps is a bad idea if you have a small space with only few plants because it will get rly hot.
You dont have to switch from 18/6 to 12/12. And what comes from the lights mh for vegging and hps for flowering (once you see some flowers on them) but ofc a mh/hps mix would work just fine.