I kept mine alive last year with my very own insane watering invention. I drilled holes in bottom of the sides of a milk bottle, about 1-2" above the base, & poked string through. I then tied knots in the strings, leaving enough that the ends of the strings rested in the base & pulled the string back through so the knots blocked the holes & filled the milk bottle with vermiculite until it was above the level of the holes. I then buried the strings in the soil & spritzed the exposed bits of string until they were soaking. I carefully filled the milk bottle with water this bit got rather messy, taking care not to disturb the vermiculite too much. I was ridiculously chuffed when we came back a week later to healthy looking tomatoes & an empty bottle that was so air-tight that it had collapsed in on itself as the tomatoes drew the water out!
I'm considering doing the same again this year purely because we had problems with flies last year & this would avoid having any accessible standing water around. I'll use a glue gun to secure the string-knot in place & make the bottle watertight so shouldn't need the vermiculite. DH is pondering how well that would work though as he thinks 'the glue may not adhere to the plastic very well'!