Ive got some new baby tomato plants- good plant feeder/ extra nutrition?

The hot weather has meant they need alot of maintenance and i was told they would need some extra nutrients on top of extra water? any ideas? something i can buy easily as the nearest plant centre is milllllllles away someone said sugar or something similar for extra glucose but that seemed a bit strange to me as sugars need to be broken down.

actually, what your baby tomatos need more than anything is nitrogen. The best source for this is manure.