I think you'd have to define "best" before your question could be answered. Money is typically the issue - what works the best is usually cost-prohibitive on a commercial scale. If you want to know what method can work profitably for each vegetable, then look at what commercial growers are doing.

As for what is best in regard to systems, high-pressure aeroponics offers the highest potential oxygen percentage in the root zone. That should in theory be best for every plant. But there are 101 other growing variables, each of which are hurdles that must be crossed before the benefits of such an advanced system could be realized. Your question is a good one, but it's very theoretical. If you want to know what works on a practical level, look at existing commercial growers.

This post was edited by Cole_Robbie on Tue, Mar 26, 13 at 13:25

Is it possible to start seeds in a hydroponic system. Mine uses lava rock for medium with felt as a "wick" into the water which has a bubbler. Can I just put the seeds on the felt to start them?

Probably. If it is quick to sprout there shouldn't really be a problem. A slow germinating seed might have more of an issue though tending to rot before it sprouts.