Cathy, have you looked at growing veggies in Earth Boxes? They are a sort of semi-hydroponic system using what amounts to a large window-box type container with a big water reservoir in the bottom. www.earthbox.com Very neat and tidy, and would work great in a greenhouse, if you don't live in the South.
I now grow all my veggies in Earth Boxes since my soil is mostly sand, and also infested with nematodes. (that's Florida for ya) The box itself is made from recycled plastic, and if you fill it with organic potting mix, and use an organic fertilizer, (the Earth Box folks offer a good one) you have a neat, uncomplicated organic growing system. Relatively inexpensive compared to a hydroponic set-up, too.
I even water mine with rain water on an automated timer system, so it's really 'natural' AND I can go away on a trip and not worry about things getting the right amount of water. Grows fabulous vegetables, too. The system is extremely water-efficient as well which also appeals to me, since rainwater can be hard to come by especially here in the winter, our veggie season.
