Wow! Those shots could be of my plants, right down to the dual runs of twine.
this issue with my plants was also touched upon here:
https://www.homebrewtalk.com/f92/sidearm-tips-limp-dying-122242/
I still haven't gotten it completely figured out, but I think I've got it down to one of two things. Maybe if we throw stuff out there we can figure it out.
Overwatering and/or a Calcium deficiency (perhaps caused by overwatering). A calcium deficiency can cause leaves to curl as the tips grow slower than the rest of the leaf. Also, leaf tips can turn black and necrotic.
Aphids can also cause leaves to curl up. Be sure to check the underside of the leaves carefully. I think I have some aphids, though I'm not sure it's bad enough to cause this much of an issue. I didn't see any aphids until after the curling started, though I've heard that aphids can start from the top down, so I dunno...
Is this mainly on newer growth? How much water have the plants been getting? If you've been watering frequently, you could try cutting back some - so long as the plants don't dry up. This has been discussed, and was successful in another thread
https://www.homebrewtalk.com/f92/black-leaf-tips-any-ideas-66429/
In my case, we've been getting quite a bit of rain and I don't think the ground has been getting a chance to dry out any. Pretty much all the leaves that have formed since the wet spell started have become curled. Perhaps my soil doesn't drain too well, or maybe a PH problem is exacerbating things. Last year I thought my Sterlings were going to die until we got a few weeks of dry weather and they came back.
Hopfully you find some of that useful.
Chris