1. the wet feet theory is a common misconception when transferring knowledge from soil to hydroponics. The wetness is anyway not the problem but the oxygenation the wetness prevents. Some plants roots are simply lacking oxygen in too wet soil or media because of there fine roots. The humidity is not the actual reason, but the cause for the lack of oxygen. As soon as there is enough oxygenation, the roots of almost any plants thrive well and stay healthy when completely
edit: emerged submerged in water.
2. Temperatures of
nutrients have priority before oxygenation. Because the cooler the water the more oxygen can/will be dissolved in water. 24°C is ideal and seen as the best compromise between ambient temperature and dissolved oxygen. If your
nutrient solution is too warm, there is no way to oxygenate it further than it can be dissolved in the actual temperature!
3. Carrots (and other root vegetables) grow well in DEEP WATER, but carrots have a tendency to crack and split in deep water culture. Some varieties tend less to split - research has been made to determine suitable varieties that split less and has shown that there are notable differences between varieties.
4. Potatoes definitely grow best in
aeroponic systems, where upper parts are sprayed (sprinklers are good enough) and lower roots are immersed in water. In Brazil such technique is commonly used. The setup is similar to concrete pools (covered with styrofaom), but there is about 1 foot of air space between styrofoam and water level. This zone is the actual growing zone which is sprayed permanently or every 15-20 mins.
5. When building a DWC setup from concrete or bricks, building it a bit deeper than 1' can be of an advantage, especially if this part is underground. Half a foot deeper may make the difference of a few degree lower temperatures and prevent you from using "complicated" perhaps delicate and energy consuming, devices.
6. In both DWC and NFT, recycling the nutrients to and through a supplementary underground reservoir is always a good idea. Constant flowing, and dropping from a certain hight may oxygenate the solution good enough. People running such- or other
recycling DWC systems, often report very good results.
PS: I am running recycling DWC based nurseries lately (with the lettuce cups filled with a perlite/vermiculite mix as shown before) and I am amazed with the results.
