GROWING IN DEEP WATER CULTURE (DWC)
WHAT IS DEEP WATER CULTURE?
Deep Water Culture - or ‘DWC’ - is a unique growing method involving the majority of the plant's root mass being permanently submerged in a nutrient solution.
No other hydroponic growing techniques (like NFT, aeroponics, flood and drain) involve the root mass being permanently submerged.
IS A DWC A GOOD SYSTEM FOR BEGINNERS?
If you are new to hydroponics, A-Grade Hydro recommends starting in a smaller system like the 19L single Oxypot before graduating to a larger system.
WHAT ARE THE BENEFITS OF GROWING WITH A DWC?
- Accelerated growth.
- Superior plant health.
- Produce is larger and more flavoursome.
- Less nutrients and additives required.
- System can be set and left for a few days.
WHAT ARE THE DISADVANTAGES OF GROWING WITH A DWC?
- More parts. Equipment such as air pumps, water heaters and pH testers are required, increasing start-up costs.
- Daily pH testing and maintenance can be troublesome.
- Weekly tank cleaning and resetting can be physically prohibitive.
- If equipment fails, there is a small window to fix and correct before plants are affected.
HOW DOES A DWC WORK?
The plants or seedlings are potted into a mesh basket and supported with an inert growing media like clay pebbles or TetraBase™. The use of an inert and hydrophobic grow medium is important as it encourages the root mass to grow downwards towards the nutrient mixture below.
The DWC tank (or reservoir) is filled with nutrient solution and fitted with air stones. The air pump sits outside the tank, connected to the all-important air stones.
A combination of warmth and aeration will create a humid environment above the surface of the nutrient solution. Eventually, the roots will find their way to the nutrient solution below.
A-Grade Tip: Top-feed newly transplanted seedling/plants with a small amount of nutrient solution until roots are visible.
CAN I USE ANY TYPE OF NUTRIENT SOLUTION IN MY DWC?
Most mineral nutrients are suitable for use in all types of hydroponic systems and growing methods. Nutrients like MILLS and CYCO can be used when growing water, coco coir and soil (always read the instructions carefully before use).
Nutrients stocked at traditional garden centres and nurseries are not always suitable for hydroponic systems and will cause many issues if not used carefully.
WHAT ELSE DOES THE NUTRIENT SOLUTION NEED?
The nutrient solution must be aerated (oxygenated) for it to be a truly effective DWC hydroponic system. This is usually achieved with the use of an air pump and air stones, which is supplied with most high-quality DWC systems.
WHY DOES A DWC SYSTEM NEED TO BE AERATED?
Most of the plant's root zone will be suspended in the nutrient solution for 8-12 weeks. The constant aeration via air stones allows the roots to form quickly and correctly.
The plant uses capillary action to transport nutrients from the root zone through the stem and into the leaves, the air contained within the nutrient solution is vital for the root zone to grow properly and to prevent pathogens forming.
WHERE CAN I SET UP MY DWC SYSTEM?
DWC's perform best in indoor grow rooms and greenhouses. Any space where the DWC tank won't get too hot or cold, and where you have safe access to electrical outlets.
WHAT IS THE IDEAL WATER TEMPERATURE FOR DEEP WATER CULTURE GROWING?
- The ideal range is 18C° – 22C°
- Temperatures below 15C° will cause a plant's metabolisms to shutdown compromising oxygen absorption and nutrient uptake.
- Temperatures higher than 22.5C° can cause pathogens and root diseases to rapidly form.
DWC & PH: IS IT IMPORTANT?
Maintaining the pH of nutrient solution is critical for plant health.
Most hydroponic plants will grow beautifully between the pH range of 5.5 – 6.5. Don't stress if the pH reading increases by 0.1 from one day to the next; this indicates a normal cycle of nutrient uptake.
Any significant increases or decreases in daily pH readings are cause for concern, and should be corrected immediately.
SHOULD I BOTHER GETTING A PH METER?
If you're a long-term hydroponic gardener, a pH meter is a worthwhile investment to add to your tool box.
For beginners, we recommend a cost-friendly pH testing kit.
WHAT ABOUT AN EC METER?
Short answer: Get one.
Daily readings of EC levels will inform you of how much food (nutrients) your plants have available to them via the nutrient solution you have just mixed together.
Different crops have different EC requirements, so following the instructions on the nutrient bottle won't always give you the correct EC level for your crop.
If the EC range of your nutrient solution goes above or below the recommended number, then some nutrients will become “locked out” to the plant, resulting in poor growth, deficiencies and/or toxicities.
We recommend the Apera EC60 Pocket Tester Kit or the Apera PC60 Multiparameter Pocket Tester Kit for dual pH and EC testing.
HOW OFTEN DO I NEED TO CHANGE THE NUTRIENT SOLUTION?
Generally, you should change the nutrient solution and clean the DWC tank, also known as 'resetting', once every 7-10 days.
At the start of any hydroponic project when the plants are much smaller and consume less, the initial nutrient solution can run for up to 14 days before it needs resetting.
As your plants and root system grow larger and require more feeding, you will need to reset the DWC tank every 7 days or so.
HOW FAR UP DO I FILL THE DWC SYSTEM?
Never fill your reservoir right up to the base of the mesh pot. Roots need water and oxygen to form so fully submerging them in water will only suffocate the plant.
Ensure the nutrient solution is a minimum of 2 inches below the base of the mesh pot. As the root mass grows, more and more will be submerged in the nutrient solution (this is ok). As long as roughly 10% of the root mass sits above the surface of the nutrient solution, the plant will get enough oxygen
6 week old jalapeno chilli plants grown in Nutriculture's Oxypot XL
Happy growing! Let us know how you go! If you have any questions ask us via the comment box below.