A DWC cannabis grow comes in many different styles and adaptations. However the common theme is that the roots are immersed in a bath of nutrients at an optimum pH, often around pH 5.8. Normally cannabis roots left in water/nutrients would eventually rot. But the presence of bubbling air (e.g. from a DWC air stone, connected to an external air pump) provides the roots the oxygen they need to grow with great vigour.
The container is often simply a deep bucket (hence the name, DWC) which is often black in colour. The absence of light keeps dreaded slime and algae to a minimum. One plant can comfortably fill the typical 15-20 litre DWC bucket full of cannabis roots by the end of the grow. A healthy root ball is a huge white mass of roots.
Many serious growers change the nutrient bath at fixed schedules, often weekly. You may be able to leave your nutrient bath 1-2 weeks between changes in veg. But in bloom, with hungry plants you should aim for complete weekly nutrient bath changes at a minimum. Pro growers may change baths even more frequently than that. They will check their baths once or twice a day in late bloom, topping up with nutrients.
Growing cannabis in DWC system.
The main attractions of growing DWC cannabis are the fast growth rates and huge yields that are potentially on offer when DWC is done well. For those that delight in the joy of growing their own cannabis, there is an undeniable satisfaction that comes from seeing a successful DWC grow really push the cannabis plant right to it’s limits.
Growing in a DWC cannabis system isn’t for everyone. But for those that do it well, dry yields of several hundred grams per plant are quite routine. Deep water culture cannabis growing pushes hydroponics (soil-free) cultivation to it’s limits. As such, it’s the ultimate thrill and ultimate challenge for many indoor growers. For those that truly enjoy their cannabis cultivation there are few more satisfying feelings than seeing a crop grow from seed to harvest. When you harvest your first DWC monster the joy and satisfaction will be remembered forever.
But for someone that has only grown in soil before there are some undeniable added new complexities to consider. You will need a, perhaps slightly noisy, air pump to feed the DWC air stone and you may need to discover the joy of owning and calibrating pH and EC meters for the first time.
Deep Water Culture (DWC) is the technique of growing cannabis plants with their roots growing in a bubbling (aerated) nutrient bath. Growing cannabis in a DWC system is claimed by many to be the fastest way to grow heavy yielding cannabis plants. However, the technical complexity of correctly maintaining the pH and concentration of the nutrients does place certain requirements on the grower. DWC cannabis growing offers great rewards, but it is far from the easiest grow technique to master.
Above the root-zone the plant grows normally, though with enhanced speed and yield thanks to the optimised conditions in the root area. The nutrient bath will need replacing frequently, especially as the plants mature. As with other grow methods, the nutrients tend to slowly increase in strength as the plant develops.
The most obsessive DWC cannabis growers change the water daily towards the end of bloom, though this would be considered excessive by many. However one primary reason why growers like to keep a fresh bath is because the cannabis roots may not use up all the nutrients and NPK minerals in your DWC nutrient line up at exactly the same rate. That means your nutrient bath could suffer an unhealthy accumulation of certain minerals. This can slow down the uptake of other nutrients. The result is a plant that struggles to grow with the nutrition it needs.
The benefits of growing cannabis with DWC.
Nutrient management in DWC cannabis growing.
Hydroponics, and DWC in particular, is a super effective way to grow weed, but there are many pitfalls. Learn to avoid them all with our DWC cannabis grow guide.
When the plants are young, their roots won’t be long enough to reach the bottom of your reservoir. During this initial period of growth, it’s important to water your plants from the top.
To set up your system, fill your reservoir with the properly mixed nutrient solution. In the beginning, when the plants are young, the nutrient solution will reach the bottom of the media.
What Is Deep Water Culture?
If you’re new to growing cannabis and don’t want to build your own system, there are plenty of DWC ready-made systems kits online with everything you need. If you want to go build your own, a DWC system has the following components:
Hydroton clay pebbles are derived from an orange-red clay and look like brown balls with black spots. They are pH neutral (inert) and come in a variety of sizes to fit your specific needs. They are also pretty cheap and can be washed, dried, and reused for your next crop.
Invest in a pH meter to regularly check the pH level of your DWC system. Ideally, keep this level between 5.5 to 6.5. If your pH goes beyond this level, consider adjusting the pH using pH kits found online.
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In a DWC system, the cannabis plant’s roots are submerged in a hydroponic nutrient solution/water. The plant’s root system is kept in place in a mesh bucket/net pot with hydroton pellets. The plants are usually housed in a self-contained and opaque container such as a bucket (at least 5-gallon).
For the best indoor grow system, refer to the greatest DWC grow start to finish guide for growers of all skill levels. Deep water culture (DWC) systems are popular types of hydroponic systems that use only water, nutrients, and a growing medium to produce stronger roots and better buds.
Recirculating deep water culture is an advanced form of the DWC system. Everything is pretty much the same except for a central main reservoir that connects to multiple bucket distribution lines and the air volume pump that recirculates and aerates the nutrient solution.
This method is particularly effective due to the constant pumping of fresh nutrient solution. In addition, the lateral flow of this system can increase your roots’ health, growth rate, and yield.
Cannabis DWC systems range in size. Some growers may place multiple plants in a single reservoir, while others may pump nutrients and oxygen into several small DWC reservoirs that hold one plant each.
In the beginning, you won’t need to replace the nutrient solution as frequently compared to when the plant has matured. How often you replace the nutrient solution depends. It could be every one to two weeks or longer.
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Hydroton clay pebbles are a good choice due to the clay’s water retention characteristics. Hydroton is capable of absorbing moisture to prevent the roots from drying out, especially in the case of a pump breaking.
As the plant grows, the solution level will go down. It’s important to check every day to ensure that your plants have the right amount of nutrient solution. Leaving them without any nutrients can quickly damage your roots and plants.
Advanced top-feeding/dripping systems continuously trickle water over the young plant’s roots. After the plants’ roots have grown enough, some growers switch back to the original DWC set-up.
A major benefit of hydroponic growing is that the plant is being continually watered. However, it’s up to you to add the missing macro and micronutrients to give your plants a fighting chance. In addition, you must regulate the pH, dissolved oxygen, and temperature of your solution throughout the plant’s life cycle.