Deep Water Culture (DWC) Hydroponic Systems
What is Deep Water Culture?
Deep Water Culture, otherwise known as Direct Water Culture or DWC, is a simple yet effective hydroponics system that works by suspending the plants’ roots directly into a highly oxygenated nutrient solution. DWC systems are proven to be very effective, easy to construct and operate, and are an ideal choice for those of you who are new to hydroponic cultivation.
Other Hydroponic Systems you should consider
- Aeroponics – This is the process of growing marijuana in an air or mist environment however without using soil or any kind of medium.
- Continuous flow – Continuous flow techniques include NFT and Drip systems. The basic concept is a continuous flow of nutrients with good drainage and flow.
- Deep Water Culture (DWC) + Recirculating direct water culture systems (also known as RDWC) + BubblePonics.
- Drip Irrigation – Also known as trickle, micro or local irrigation. Uses small emitters to drip nutrients directly onto the roots or soil of your plants. Saves water and nutes, can be used with mediums and soil.
- Ebb and Flow – Or Flood and Drain hydroponics is simply a method to flood your pots with a nutrient solution at regular intervals and then let it drain back into the reservoir.
- Nutrient Film Technique (NFT) – Nutrients are pumped from the reservoir into a tray to form a thin film of nutrients constantly flowing with the roots of your marijuana plants dipped in them. There is no growing medium.
- Wick system – One of the most basic systems to use, if you are just starting out and want to get going today, try this.
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DWC V Bubbleponics V RDWC
Before we explain the system in more detail, including how to build your own DWC system, it is worth taking a look at some of the terminology that you will come across when researching DWC systems. There are several different types of DWC system and in some places the names have become interchangeable, which can sometimes be a little confusing.
- Deep Water Culture is the basic system we will describe here. It uses just one bucket or container, which serves as the reservoir for your nutrient solution;
- Recirculating Deep Water Culture (RDWC) works on the same principle but has a separate central reservoir which feeds several buckets;
- Bubbleponics is the term that causes most confusion. Bubbleponics has been widely used as a marketing term and, as such, its exact definition has become somewhat elastic. The correct definition of bubbleponics is a DWC system with a top feed. Basically oxygenated nutrient solution is pumped and fed to the plants from the top of the root system rather than just bubbling away below the roots.
How Does DWC Work?
One of the most attractive factors of a DWC system is its simplicity. The roots of marijuana plants just LOVE oxygen. The roots can’t get enough of it and increasing the oxygen available to them massively increases their uptake of nutrients, which of course means more growth. This is why, in soil systems, we add Perlite and Vermiculite to introduce air pockets to the medium.
All hydroponics systems require a method of allowing the roots to come into contact with the air. Often, as in Ebb and Flow systems, this is achieved by having regular timed flows of nutrient solution interspersed by dry periods when the roots can breathe. With DWC the roots are permanently suspended in the nutrient solution and the oxygen that they require is also in the solution. Here’s how it works:
- Plants are grown in net pots suspended in the lids of plastic buckets;
- Plants are normally started out in Rockwool cubes which are then placed into the net pots which have been filled with an inert growing medium, normally Hydroton or similar expanded clay pellets;
- The bucket is filled with the required nutrient solution;
- An aquarium air stone is placed into the bucket and an air pump attached using air lines;
- The roots of the plant grow downwards into the nutrient solution, becoming permanently suspended in the liquid where the extra oxygen allows them to assimilate the nutrients.
Buying a DWC System
There are a number of DWC systems available on the market and, if you are not very handy at DIY then this could be the answer for you. Remember that the value of this system is in its simplicity. There is no need to spend ridiculous amounts of money on this. Things that you should consider before purchasing are:
- Air Pump Power – The air pump is the heart of your DWC set up. The air pump needs to be powerful enough to sufficiently oxygenate your nutrient solution. The more bubbles you have, the better this will work. Do not be tempted to skimp on the pump. A good rule of thumb here is around one Watt per gallon. That means a 20W pump should be enough for a 20 gallon reservoir;
- Air Pump Noise – Stealth is a serious issue for lots of growers. It’s not just the neighbors either, nobody wants to be kept awake at night by the sound of a humming pump. Some of the cheaper imported air pumps can be noisy. All good air pumps will advertize their operating noise levels. Noise is measured in decibels. Use the image below to get an idea of how loud a given amount of decibels actually is;
- Air Stone – DWC is all about the bubbles, make sure the system you buy comes with a decent air stone. At least 4” – 6” for a single bucket system;
- Bucket Size – A 3 – 5 gallon bucket is the minimum size you would want for a single plant set up.
Construct Your Own DWC System
Building your own DWC hydroponics system is really easy. If you are good with your hands then you will be able to knock one up in no time. Even if you’re not so handy, the concept is very simple and by following these straight forward instructions you should have no problems constructing your own system.
Use this DWC tutorial as a basis for your own system. Once you get the hang of the concept you can consider expanding and setting up multiple systems so that you can grow several plants at the same time.
Like the satisfaction of growing your own vegetables, your weed will taste much nicer and feel more potent from a system that you have built yourself!
Tools and Materials You Will Need:
- Drill with ¾” drill bit and either 3” or 4” hole saw attachment (if necessary, see lid below);
- 5 gallon opaque bucket;
- Specialist net pot lid to fit the bucket, available from your hydro store;
- If you cannot get a net pot lid use a normal bucket lid and either a 3” or 4” net pot. This is where you will need the hole saw;
- Aquarium air pump;
- Approx 5’ of ¾” silicon or rubber tubing (not transparent);
- Aquarium air stone;
- Expanded clay pellet growing medium.
- Drill a ¾” hole in the side of your 5 gallon bucket, around an inch down from the top. This is for the airline to enter the bucket so it is important that the hole is above where the top of your nutrient solution will be, but does not interfere with the lid;
- Make sure your airline fits through the hole snugly;
- Thread the airline through the hole and attach it to the air stone. Place the air stone inside the bottom of the bucket. If the air stone has suction pad attachments, attach them to the bottom of the bucket. If not, make sure that the stone is somehow attached firmly to the base of the bucket;
- Attach the other end of the airline to the air pump. It is important that, when the system is operating, you position the air pump higher than the bucket. This means that, should the air pump fail, the water will not run back through the airline and flood the pump;
- At this stage it is worth putting some water in the bucket and turning the pump on to check that you are getting plenty of bubbles. Are you? Great!
- Now, if you haven’t bought a specially made net cup lid for your bucket you will need to drill an appropriately sized hole in the lid of your bucket. Net cups come with a small lip for attaching, so you just need to drill a 3” hole for a 3” net cup or a 4” hole for a 4” net cup;
- Use some silicon (or other appropriate waterproof adhesive) to attach your net cup to the lid;
- That’s it! It really is as easy as that. A small hole for the airline, a larger hole for the net cup (if required), join the airline to the pump and air stone, and you are ready to grow some serious weed!
Variations you may wish to consider include:
- Multiple net pots for multiple plants in a bigger bucket or other container;
- More than one air stone for more bubbles, use a T-Bar to join them;
- A powerful, multiple outlet air pump feeding multiple buckets.
Operating a DWC System
Once you have either bought or constructed your Deep Water Culture hydroponics system, you will be keen to get started with the growing. You can either germinate seeds or start with a clone. You can read more about that in the appropriate sections of the website.
For the purposes of these instructions we will assume that you have a rooted clone or seedling in a Rockwool cube.
- Fill your bucket with your nutrient solution. Make sure that the top level of the solution comes to around the bottom of the net cup. It is important that, at this stage, the growing medium is not submerged in the solution. The idea is that the roots grow down into the solution. There will be enough humidity from bubbles breaking the surface to keep the young roots moist and happy;
- Fill your net cup almost to the top with your growing medium of choice. We recommend expanded clay pellets;
- Place your rooted plant, in its rockwool cube, into the growing medium so that the top of the cube is just covered by the top of the medium;
- Turn the pump on;
- You are now growing hydroponic marijuana;
- There is some debate going on about whether to have the air pump for a DWC set up on 24/7, or whether to use a timer. Some folk use a timer set for a few minutes on then a few minutes off. It is our experience that most growers go for 24/7 and that is our recommendation;
- Be sure to regularly monitor the pH and concentration (EC or PPM) of your nutrient solution. This is important. Keep pH between 5.6 and 6.2 and carefully follow the feeding program that comes with your chosen nutes;
- Change your nutrient solution and clean the inside of the bucket around once per week;
- Before long your plant will develop a massive root system. Seeing this explosive root growth every time you change the solution is one of the most exciting bits about DWC hydroponic cultivation:
- Once your plant is well established and you commence flowering, you can lower the level of the nutrient solution by a few inches so that most of the roots are submerged but the very top section is open to the air.
Deep Water Culture is an excellent hydroponics system that should be of interest to both novices and experienced hydroponic growers.