Why is it called Deep Water Culture?
“Deep Water” because the plants are growing in a pool of water instead of a growing medium, and “Culture” is a word that can also mean “Cultivation”.
Vegetative plants growing in soil spread out a huge system of roots. The roots then search for nutrients and draw it from the soil. But roots in soil also need to find oxygen to prevent the plant from “drowning” (when a plant droops after over watering this is because the medium is soaked and the roots can’t find any oxygen pockets.
When growing using a DWC method, the roots don't need to spread out, and search for the nutrients since everything the plant needs is readily available in the most absorbable form possible. The dissolved oxygen in the water from the air pumps, gives the roots almost unlimited oxygen and prevents the plant from getting “over-watered” or droopy even though the roots are submerged in a reservoir of water. This decreased effort in having to ‘find’ nutrients and oxygen gives increased vegetative growth and lots of foliage, especially if a high density of light is provided.
R-DWC is a type of DWC where several DWC bubblers are connected together and a pump circulates the nutrient solution around them constantly.