Due to sheer volume of soil, nothing holds moisture like a big old jug- either milk jugs or 2 liters. Any cups will dry faster due to smaller volume of soil. I do usually use a few styro cups (8 oz. and 16 oz.) and a few 6 oz yogurt cups and don't find that they dry out all that fast. The worst for drying out are paper cups and peat pots. I tried those in my first year, won't do that again.
Karen
