Potting mix for greenhouse containers
So I've looked at a lot of threads concerning the proper potting mix for containers (really want to try out Al's mix) but have a problem. I plant a lot in a university greenhouse that's a long way from home (14 miles), and can't go to water the pots every day during summer. What potting mix would you recommend that is soil-less but retains enough water for a plant for at least two days? I grow mostly vegetables.