A Deep Look At Deep Water Culture
Deep water culture is a method of growing plants hydroponically where the plant's roots are suspended in a solution of nutrient-rich, oxygenated water. Here's everything the first-time hydroponic gardener needs to know about this growing system.
Making the choice to garden using hydroponics is an easy one. The advantages of hydroponic gardening over traditional methods using soil and soilless mediums are numerous. Plants grown with hydroponics grow faster and healthier, meaning larger yields and quicker crop rotations.
Hydroponics is a cleaner way to grow—keeping soil out of the growroom means less root-borne insects, less work keeping your room tidy and no more trips to your local hydroponic retailer for large, cumbersome bales of soil/soilless mixes, which also means more money in your pocket. Hydroponic methods also use less water than traditional methods.
The difficulty once you have decided to grow plants hydroponically is choosing which method is right for you. There are so many options out there, each with its own benefits and drawbacks. One of the easiest and most effective methods for the first-time hydroponic gardener is the deep water culture system, sometimes called the direct water culture system.
What is DWC?
Deep water or direct water culture is a hydroponic method of gardening. There are various DWC systems, but the basics remain the same. Some are single plants in individual buckets while others have drilled out trays that fit multiple plants above a larger reservoir. The hydroponic solution is aerated by an air pump and an aquarium air stone. Like all hydroponic systems, you must balance the pH of your water between 5.8 and 6.4.
Start your seeds or clones in a hydroponic medium such as rockwool. Once there is significant root growth—an inch or two out the bottom of the starter cube—the plant can be placed in a grow basket and surrounded by another hydroponic medium such as expanded clay, volcanic rock or diatomaceous earth.
These mediums are inert and will anchor the plant and wick up water. The basket containing the plant is placed directly above the reservoir containing the hydroponic nutrient solution so that the baskets are barely in contact with the water and roots are slightly submerged. At first you must mix your nutrient solution at quarter strength.
This will keep plants from burning, but it will also coax the roots to grow downwards into the reservoir in search of nutrients. As the roots grow you can gradually increase the nutrient dosage to half strength then to full strength.
What are the advantages of a DWC Hydroponic System?
There are numerous reasons to try a DWC system. These systems are compact, making them a great choice for people with limited space to grow, like a closet or a small countertop.
DWC systems can be more affordable for the first-time hydroponic grower. You don’t need a water pump since the roots are directly in the water, the systems can be easily made from buckets, kiddy pools or anything else you can cut a hole into and suspend a plant from, and growing mediums such as expanded clay can be cleaned and reused.
DWC systems are easy to use and maintain. Other methods such as flood and drain tables require the grower to make sure they are flooding often enough so the plants don’t dry out, but not so often the plants drown. Expandable drip and aeroponic systems also require closer attention than DWC. You must make sure the drippers and sprayers are not becoming clogged and that they are all spraying and dripping evenly.
What are the disadvantages of a DWC Hydroponic System?
There are a few drawbacks to DWC systems. The main limitation is the size of the system. Since the roots are directly in the hydroponic nutrient solution, you need to match the plant area with an equally large reservoir. For instance, if you want to grow in a 4-ft. by 4-ft. space, you need a 4-ft. by 4-ft. reservoir. The tray and reservoir must be together, so weight can be an issue if you want to keep the system off the floor.
DWC systems are not expandable—the plants are fixed in place and they cannot be spread out to prevent crowding or shading, whereas other systems like flood and drain and expandable drip systems can be expanded. The roots of plants grown in DWC systems will inevitably become tangled with each other, making moving them around without causing root damage impossible.
For those adventurous gardeners looking to take the leap from traditional container gardening to hydroponic gardening, deep water culture systems are the logical first step. You will get great results and begin to amass the knowledge required to become a successful hydroponic gardener.