A Primer on Deep Water Culture

Deep water culture (DWC) is a type of hydroponic gardening in which the roots of a plant are suspended in a solution of oxygenated water and various nutrients.

Traditionally, DWC has been practiced using plastic buckets. The plant itself is suspended in what is known as a net pot. This net pot – a type of pot resembling an open wire basket – is suspended from the bucket lid in such a manner that the roots are suspended in the bucket containing the water and nutrient solution. The water is oxygenated with an air pump and an aquarium airstone such as are used in fish tanks.

Once the plants reach the flowering stage, the level of the nutrient solution is reduced, gradually exposing the roots to the open air, where they can absorb greater amounts of oxygen. The massive ingestion of oxygen and nutrients leads to maximum growth throughout the plant’s life cycle.

A variation on DWC is recirculation deep water culture (RDWC). An RDWC system employs a reservoir which in turn provides water to several buckets. If these buckets are not connected in some way, it will be necessary to test each one for proper pH levels (acidity vs. alkalinity) and conductivity factor (CF, a measure of electrical conductivity used to determine nutrient levels).

In order to avoid the need for testing of each individual bucket, some RDWC systems dispense with the air stones and instead connect the buckets. The water is recirculated with spray nozzles, resulting in better aeration and oxygenation. By constantly recirculating the water in this fashion, nutrients are mixed more effectively and pH levels are stabilized throughout the system.

Building a DWC grow system is neither particularly difficult nor expensive, and can be done for under $100. To start, you will need a five gallon bucket, a fish tank air pump, an aquarium airstone for breaking up the bubbles, a six inch hydroponic growing net or net pot, duct tape, and a hydroponic growth medium (organic composted bark is best).

The first step is to cut a hole in the bucket lid that is the same diameter as the net pot. The net pot should fit snugly when the lip rests on the edge of the pot. You’ll also need to cut a small hole in the side of the bucket near the top in order to accommodate the air line. This should be run down to the bottom of the bucket and into the airstone.

The bucket should then be wrapped in about five layers of duct tape in order to prevent any light from reaching the reservoir (which would lead to the growth of algae).

The net pot is then filled with the growth medium and the seedling of the plant you are attempting to grow. Fill the bucket with clean water, put the lid in place, insert the net pot, turn on the pump, and your new system is in operation.

Susan Slobac is a hydroponic gardening enthusiast who has had experience with a variety of hydroponic gardens. Most recently she has been using the method of deep water culture in her hydroponic garden and has had great success.