I have the same problem in my area, PM is everywhere. It is manageable though. One way to manage it is spray regularly, whatever you choose, do it regularly in veg, most times you won't see it in flowering if your airflow and humidity are in check, spraying in flowering is not nice for your buds but I've done it (baking soda mix). Another way is to learn to recognize early signs of it in veg and cull anything that is susceptible to it. Over time I've found certain strains, and even in some strains, only certain phenos will get it while others are almost immune to it, so recognizing it and early culling is good practice (not like it's going to go away, or even be prevented from getting some spores back in your room if your area is covered in it). I have also tried HEPA filters in my room, the one I have is rated for 4x the size of the room but by itself it's not good enough. You shouldn't think that keeping humidity low and lots of airflow is good enough, if it's in your area you will get it without putting other preventative practices in place.
Spring for me is one of the worst times when the snow is melting and ground is thawing. It's been guaranteed to show up in spring here, even with spraying if I have any phenos going that are susceptible to it. So for the last 4 weeks I tried adding a new device and so far I haven't seen any signs and I haven't sprayed any of the plants in my flower room, this is looking very promising, I should have seen some in my room by now as I have a run of seeds going and I doubt every single pheno is immune (maybe but unlikely).
The unit is an air cleaner but using UVC technology vs. filters like the HEPA style air cleaners. It's also rated for about 4x my room size, but the air is sucked into the unit where it passes through an internal chamber bombarded by UVC. For me the $100 I paid for it is peanuts if this thing can keep PM out of the room and so far so good. This is the first time since I found PM in my area that I have some hope that there's a solution without the f'n spraying and constant monitoring. Keeping fingers crossed but based on the time of year, running 9x new plants from seed (~ 4 phenos) and none of them showing any signs of PM, it's looking very good. Here's the unit, I'm sure there are others out there but this one was the only one available locally in CAD and had replacement bulbs readily available locally. The unit ships with a spare bulb and they recommend to change them out every 6 months, they cost peanuts compared to HEPA filters so if this proves to work consistently it's a very good option if not the best option for scrubbing the air if your area is infested with it. Of course maintaining your environment like RH down, lots of airflow etc. is important but I've seen it regardless of those factors being in place. Cheers.
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