This is mite damage! Hemp russet mites in all likelihood. Before you go too crazy flushing your soil or making radical changes in your tents, Google images of mite damage and see if anything looks similar to what you're dealing with. Severely infested plants should be trashed, possibly burned even. I let most of them freeze to death outside. The rest will be washed off with Lost Coast Plant Therapy unless I need something stronger. I don't think grow sites emphasize integrated pest control enough. This is not a problem most growers will know how to handle until it takes down enough of their plants. 1/31/2022

I've had another batch in veg turn up this way. The new growth crinkles up and growth nearly stops. I let the humidity levels fall too low. I have an Alien Rock Candy that isn't affected because it was transplanted later than the rest after I figured out that the low RH was screwing everything up. All else was the same.

Here's a sample:

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I've got two new Niwas keeping things in line now. I thought for a while it was brought on by stress from manifolding them so I laid off cutting on the ARC until this week after I was satisfied that she was healthy enough. Still, I only gave her a simple topping. New growth looks fine on her. I forget which one this one in the photo is, but it's probably Expert Gorilla (not that it matters). I've got another batch in the nursery so it's not such a disaster if they can't be saved, just a shame that I had to learn this way. It's just another one of those things that I never had to deal with in hydro.