I have grapevines growing up around my hot tub and the one side is perfectly fine and healthy and the other side the leaves are turning brown and curling. Could this be from chemicals from the hot tub or do they possibly have Pierce disease? or what? I know they are getting enough water etc.
It is possible that it is Pierce disease. https://www.gardeningknowhow.com/edible/fruits/grapes/preventing-pierces-disease.htm
If you know that the area of the vines is being exposed regularly to the vapors from the hot tub and the unaffected vine is not then I’d suggest that that is the more likely problem. If the hot tub water is soaking into the soil, then that will definitely cause problems for the grapes. Also make sure that you aren’t overwatering them…this also can cause problems. Never spray water them…wet the soil, never the leaves.