A search for "tomato leaf curl" and "tomato leaf roll" here at GW will get you many threads and links to review. While it can be caused by a bad infestation of aphids or whiteflies. Assuming you don't have those, then it is the normal physiological response of a stressed plant - too cool, too wet, too dry, too hot, too much fertilizer, too many fruit, etc. All those factors can cause side-to-side leaf roll.

It usually does not affect production. Since yours are in a greenhouse and it is affecting more than one plant, I would first suspect temps need modification. Then review and alter your watering program - too dry is much better than too wet - and see if it improves. Good luck. :)

Dave

thanks for reply i will try the watering option as none of my tomatoes in grow bags are leaf curling just the ones in tubs,they do not have aphids on them or white flys.