I've never heard of an air purification system being ran specifically for the purpose of aiding marijuana growth. My gut tells me it would have little to no noticeable effects. If I had one just laying around the house, I'd probably use it. At least for the fan if nothing else. But I highly...
Anything you do to stunt the growth of your plants will harm your overall harvest in the end. You would need to deprive (a.k.a) starve the plants of something, like nutes or lights to slow growth, I don't personally recommend taking anything away. That's like saying my kids are to healthy so I...
A rough rule of thumb, "the thinner the fan leaves the longer the flower".
But you can only rely on tricombe color to tell when it's really time to harvest.
Am I reading that correctly, you have 20 flowering plants using only a single 600w HPS and 4 6w led bulbs?
Sounds like you need at least 2 more HPS lights. Assuming you stick with 600w.
And better pictures.
Seedling stretch is common and not really something to worry about in the early stages of their life As long as you have appropriate lighting and it appears that you do. However there are lights that are better suited for seedlings and will help prevent stretching but once the plant develops...
Honestly I wish more people would do this. There's no such thing as being too safe. Especially since smoke detectors are a dime-a-dozen. There is really no reason not to have one. No one needs to wear a seatbelt until you get in a wreck. As far as light pollution goes, 99.9% Of smoke...
Your girls look great keep up the feeding schedule with Fox farm and make sure to stop feeding the last 2 weeks of flower and feed only RO water and you should be good.
Let the flowering commence. It's that time of year again for the outdoor guys. Mine just started to show early stages of flowering about a week or so ago.