What's up with these suddenly curled leaves?

so I've got four plants that just started their second week of flower and during this first week when the buds started to form all the surrounding leaves started curling down like crazy. I have 3 plants of the same unknown strain and one little tangilope plant but they're all doing the same thing. I would say possibly nute burn/toxicity but it even happened on the one plant I've noticibly underfed. Maybe over watering? Another thing I've noticed on two of the plants is some rusty looking leaves? I'm not completely sure so I'd like some second opinions.

Anybody?

How much have you been feeding?
Plants not drinking as much?

I was feeding them the biobizz starters pack line once a week, but for the last two weeks they've all been getting just phed water with the exception of the yellowish plant, I've continued feeding that one. They're in 4 gal pots of ffof and I feed them each about half a gallon of the nutrient solution

NorthernOregonAdventures said:

I was feeding them the biobizz starters pack line once a week, but for the last two weeks they've all been getting just phed water with the exception of the yellowish plant, I've continued feeding that one. They're in 4 gal pots of ffof and I feed them each about half a gallon of the nutrient solution

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They look overwatered and just so you know ffof buffers itself ....there's no need to adjust ph with ffof .....is your soil draining well are you letting it dry ...and the last plant looks underfed IMO

Too much nitrogen.. leaf curl on new growth.. yellowing and burning of older growth..