[GpsFrontier]

Hello Kframe'
you have a lot of goals. For root veggies use a sand based growing medium (large grain sand). Mix it with perlite and/or vermiculite for moisture retention and aeration. I would suggest running it as a drip system. Sand drains well (to well, hence the perlite and/or vermiculite), but it also provides a soil like texture for good shape/development. Also the perlite and/or vermiculite adds areation for the roots. Sand also provides weight that mimics soil. I finished building just such a system for growing radishes and green onions today. There will be a difference between crops. You will need a much deeper growing area for potatoes, carrots etc. than you would for radishes etc.. So designing it depends a lot on what/and how much you expect to harvest. Onions fall under a root crop as well.

From what i have seen, for the non root crops, i can use either a dwc or ebb and flow. my question is What is the differences between dwc and ebb aand flow, i just cant see a difference, but im new.

DWC (deep water culture)
is just a variation of a water culture system. A water culture system consists of the roots being submerged in the nutrient solution 24/7. It uses a air pump to pump air bubbles thought the water. The air bubbles are necessary to keep the roots from suffocating, and providing water movement in the container (that would normally be provided by a water pump).

Ebb and Flow (and/or Flood and Drain)
Unlike where a water culture system (DWC included) where the roots are continuously submerged in the nutrient solution. A ebb and flow (flood and drain) does just that. It floods the roots for a period of time, then drains the water (nutrient solution) from the area. The roots are kept from suffocation because the the water is periodically drained from the root area.

For lettuce crops I would go with a water culture system. Broccoli, i would go with a drip system. For green beans, I would go with either a flood and drain, or drip system.

i have thought about a general hydroponics drip ring system, but for the life of me cant figure out how t hings grow in the middle of the drip ring, when no water./nutrients are dripped there.

It depends a lot on the growing medium used, how much of it there is, and how often they dippers run. Water runs downhill, but a growing medium that absorbs moisture well will wick it up easily. That sucks the moisture into the center of the container near the plants. I attached a picture of a drip ring I created for a broccoli plant that worked great using coco chips for a growing medium. You can see by the later picture it worked fine.

root crops like carrots require only a little space and one pot can hold many carrots, so i wounder how a drip ring would handle small root crops. sure it would work for a single potato plant, but i cant have potatos so no go there..

It works just like it would if you were using drip lines for soil. The moisture is wicked up by the growing medium, but does drain down hill. The moisture spreads out thought the growing medium, but it can only spread so far from the drip point/s. That's where your design, and choice of growing medium come into play. Again I was using coco chips, but if you look closely at the pics of my melons ,you can see the black tubing on top of the growing medium. I made holes in it and used the tubing ad my drip ring.