There are many different varieties of hydroponic systems. One of the most popular of these is Deep Water Culture, AKA, D.W.C. Growing cannabis in DWC will bring you big plants, with heavy yields. But, it can seem to be a complex system to work with, if you have not grow in DWC before.
This guide is to help you get an understanding of deep water culture, and how it works. By the end of this guide you should be fully prepared to set everything up, and start growing cannabis in DWC.
If you have any questions about DWC, and you are thinking about starting to grow in deep water culture, then feel free to ask for help in our cannabis growers forum
What is DWC?
Growing cannabis in hydroponics usually means, growing in a water, or a soilless medium. Deep water culture is a type of hydroponics, where the root ball of a plant, is grown into a large container full of water.
This water will have nutrients dissolved into it, and an airstone will be used to provide the root zone with plenty of air. Together with air, nutrients and water, the root zone can drink, eat and breathe a lot! This will make plants grow quickly, and will result in bigger yeilds, in less time.
DWC is one of the most popular ways to grow cannabis hydroponically. It is easy to do, and there isn’t a lot of equipment you need to get started. You can buy a DWC system from many places online, or your local hydro store. And, you can also make your own.
What you Need to Grow Cannabis in DWC
We will assume that you already have your grow tent, and equipment ready to go, and you are just deciding what medium you are going to grow in. If you need help to decide on the right grow tent for you, then take a look at our grow tents section.
For growing in DWC, you do not need a lot of equipment, and what you need is easily sourced:
- Large Container for Root Zone
- Air Stones
- Rockwool Cubes
- Clay Pebbles
- Your choice of Salt Based Nutrients
- Reservoir Cooler (Possibly)
1) Container for Root Zone:
For each plant, it is ideal to give at least 20-25L of root space. The more space the roots have to grow, the bigger your plants will be. I would recommend you buy a DWC bucket, with a netted pot. These are designed specifically for growing cannabis in DWC.
This kit will come with the netted pot for holding the cannabis plant and roots. An air stone and pump to supply oxygen to the medium. It also has a tube on the side, that will allow you to link multiple pots together, or easily drain the reservoir.
This kind of pot, is for one plant, but there are DWC systems you can buy that will hold multiple plants in one reservoir. These can be expensive, and I would advise against growing many plants in one container unless you are growing from cuttings of the same strain.
2) Air Stones
The roots of a cannabis plant need oxygen in order to eat. Because of this, airstones are a vital piece of equipment when growing in hydro. You must ensure you have a good, reliable model. Also, you must always make sure that the pipes are not blocked, or tangled with roots.
If the air supply to the roots stop, your plants will stop eating, and the root zone will begin to rot! Do not underestimate how important it is to keep fresh air flowing to your root zone. Get a good airstone and pump, and have it running 24/7.
3) Rockwool Cubes
You won’t be able to start off your plants straight away in DWC. You need the roots to grow long enough to reach the water first. If you are growing with a cutting, that is already rooted, then you just need to plant it into clay pebbles.
But if you are germinating a seed for DWC, you need to give it a place to settle and grow, before it goes into the bucket.
The cubes should have been sat for 24 hours, in water, that has been ph’d at 5.8. Then, when you plant your seed into the rockwool, the ph will be perfect.
After a few days, maybe a week the tap root will grow through the bottom of the cube, and can be planted into the netted pot. To help support the rockwool cubes, you should use clay pebbles
4) Clay Pebbles
Place a few clay pebbles at the bottom of the netted pot, so there is a layer a couple of pebbles high, for your cube to sit on. Treat the clay pebbles like you did the rockwool. Leave them to sit for 24 hours in ph’d water at 5.8.
Lower the root gently, through the pebbles if you can, try and get it close to the water. It doesn’t need to be able to reach it just yet. Just get it as close as you can. The bubbles formed by the airstone, will splash up to reach the roots. You might have to feed from the top for a few days until the root touches the water, but it will not take long.
After the rockwool cube is sitting comfortably, fill around the sides of it, and a layer over the top. Now, your plant is ready to go, and will live the rest of its life in this bucket.
5) Your Choice of Salt Based Nutrients.
This is always down to personal preference and where you live in the world. Some foods might be unavailable to you, or they may need to be shipped to you, which will be expensive.
When growing cannabis in hydroponics, it is always better to use salt based nutrients. It is possible to grow organically in DWC, but, it is not easy, and it can get messy! When growing hydro, stick to salt based nuits, if you want to grow organically, grow in soil.
Advanced nutrients, Canna, Dutch Pro, Samurai, there are so many brands to choose from. They are all good, and when used correctly, can grow amazing plants. You will also need H2o2, and PH Up and Down.
The most important thing you should consider is the BG EC of your water, and if you live in a hard water area. If this is the case, consider reverse osmosis, or nutrients designed specifically for hard water areas.
6) Reservoir Cooler
The temperatures can rise in your reservoir, and it will affect the way bacteria grows, and the way oxygen is dissolved in the water. For ideal nutrient uptake your reservoir temperatures should be around 18c at all times.
As summer months come, or if you’re growing with HID lighting, it can be difficult to maintain a steady temperature in DWC reservoirs. You may need an aquarium cooler, that keep the temps at optimal levels.
Feeding Cannabis Plants in DWC
If you can find the right balance when growing cannabis in DWC, you can offer your plant the right diet. This means you can feed it correctly though its whole life cycle. By monitoring the water levels, the EC, and the Ph of your medium, you can keep track of what your plant is and isn’t eating.
When the plant first shoots above the rockwool, you should feed at a very low EC. Just add a small amount of grow foods, just 0.1 EC over your BG EC, and feed from the top, until the roots touch the reservoir.
When roots are in the water, and the airstone is bubbling away, the plant can eat a lot more. But you should still take it slowly, and raise in small increments.
The EC of your res for seedlings, should only be around 0.2 EC over your background EC. You can the follow the PH and EC of the res to determine how to proceed with the next feed.
To ensure a healthy root zone, the reservoir of your DWC bucket must be kept clean! Keep your temperature of the res around 18c, and a constant supply of air, and problems will not arise often. But once a week, with a maximum of 10 days, you should clean out your reservoir and replace the nutrient solution completely.
Your roots should be a healthy white colour, if at anytime the root zone begins to smell badly, and the roots turn mushy and brown, root rot is setting in. Use H2o2 to clean the root zone and res, and change the water.
It is important to maintain a clean healthy root zone, as this is where your plant will get a lot of its nutrients. Give it the right environment, like you would do with your plants above ground, and the plant will thrive! Just do not over feed, and follow the EC and PH of the res regularly.
Final Notes on Growing Cannabis in Deep Water Culture.
Growing cannabis in DWC will take more time, and maintenance than growing in soils. But, for some people it works better. Regular routine checks and a system to follow can make it very easy. You pretty much just have to follow the instructions from the plant.
Reservoir temps, air to the root zone, and a regular check of EC and PH, will see your plant reach harvest healthy. Just make sure you do not over feed the plants, as it is very easy to do!
Our Cannabis Growers Forum
Thanks for reading! You can find more information on anything related to growing in our cannabis grow guides. All of our guides are written by experienced growers, and members of our cannabis growers forum. If you have any questions, sign up. It is free, and we are always happy to help!
Stay safe out there, and happy growing.