How to Grow Cannabis Plants in Deep Water Culture

Deep Water Culture (DWC) is one of the most effective yet niche techniques of growing cannabis. 

Also known as bubbleponics, it’s easy to set up and grow plants effortlessly. 

Many growers claim it's the fastest way to grow high-yielding cannabis plants with potent buds — and rightly so! 

Essentially, DWC is a technique of growing the plant with its roots wholly submerged in an aerated nutrient bath or nutrition solution. 

Sure, growing cannabis in deep water culture offers some terrific benefits, but it can be complex for many growers. So whether you are looking to set your foot into DWC cannabis or improve your yield, this article shows you how to do that properly.

DWC Cannabis: Behind the Scenes

You can grow cannabis using deep water culture in various styles and adaptations, but we will introduce you to the most basic setup first, so you get a clear idea of what DWC really is. Moreover, it’s perfect for beginners. 

A basic DWC setup for cannabis uses a net pot to hold the seedling and clay pebbles. Then, we have some air stones and a light-tight bucket to hold the nutrient solution and lighting equipment. 

Here, the bucket that is often black contains the solution that is pH balanced between 5.5 to 6.5 — the optimum pH for growing cannabis hydroponically. Remember to balance the pH regularly to avoid nutrient deficiencies. 

Typically, if you submerge the plant's roots in the nutrient solution for so long, the roots would rot or burn out. To remedy this, you have to use air stones to aerate or offer adequate oxygen to the roots to grow correctly. 

The dark container also ensures no algae or bacteria grows within the bucket and infests the roots. 

Apart from this, DWC for growing cannabis is quite similar to other forms of hydroponic systems — simply replace or top up the solution on time, offer proper light and temperature, and pamper the plants with some love, of course. 

Now, why is this better than other hydroponic systems? Let’s take a look.

Benefits of DWC for Growing Cannabis

Let’s be honest — DWC is not everyone’s cup of tea. It can be complicated, and setting it up can be time-consuming. You also have to be meticulous with the pH and EC meters. There are other ways to grow cannabis hydroponically, but DWC is totally worth it — ask any veteran DWC grower!

Here are a few reasons why DWC is loved by many experienced cannabis growers around the world:

• Faster growth: Deep water culture is perhaps the quickest way to grow cannabis in your home, thanks to the meticulous process and constant supply of nutrition and oxygen via the deep bucket.
• Immense dry yield: DWC, accompanied with proper growing technique and care, can yield massive results, literally, up to several hundred grams of buds per plant!
• Fewer chances of bugs: The DWC cannabis plant is soilless and grows in a controlled environment, protecting it from bugs and even mold or rot infestation.
• Simple to maintain: The process may sound complex at first, but it is pretty easy to maintain once you get the hang of it.

Growing cannabis with deep water culture offers you the ultimate thrill and challenge and helps you push your growth skills to their limits. So, if you are looking to take your cannabis-growing hobby to the next level, DWC is the right option for you.

Deep Water Culture for Cannabis: The Nitty Gritty

Of course, DWC for growing cannabis is a game-changer, but the benefits don’t come easily. Unlike a set-it-and-forget-it hydroponic system, the DWC system requires you to pay close attention to the environment for a successful yield. 

So, let’s look at the various environmental aspects: 

Nutrition Management 

Nutrition management is perhaps the most crucial aspect of growing DWC cannabis. Here, you can choose either of the two popular schools of thought — replacing the nutrient bath regularly or only when the plant requires it. 

Some DWC cannabis growers swear that the plants do best when they top up the solution only when required. This is because the solution offers the right ingredients to the roots at all times, and you only have to top up when the water levels get too low.

On the other hand, some veteran growers like to replace the nutrient bath regularly — some even do it daily. This is because the plant’s nutrient requirements change with time as the plant develops. 

And, since the roots may not absorb all the nutrients and NPK minerals at the same rate, the nutrient solution may suffer an unhealthy accumulation of certain minerals, which can slow down the plant’s growth.

Who’s right? The debate can go on forever. We recommend you take the middle ground.

If you research growing cannabis using DWC, you already know a lot about the correct nutrient solution. Still, we recommend you use a more dilute nutrition bath at the beginning to avoid nutrient burn and work your way up to a stronger nutrient solution. 

For instance, use only half-strength nutrients on the first week of the vegetative stage. Note that we are talking about the vegetative stage and not the seedling stage since utilizing any type of nutrient when the seedling is fragile can be detrimental. 

And if you spot a nutrition deficiency at any stage, you can fix it by simply flushing the nutrient solution and starting with a slightly stronger solution. Remember — fixing nutrient burn can be more complicated than a deficiency. 

We also recommend investing in pH and electrical conductivity (EC) meters to keep an eye on the nutrient solution. 

You can use the same nutrition solution for a couple of weeks during the vegetative stage but regularly check the solution with your pH and EC meters. And always be wary of any signs of nutrition burn or deficiency on your plants. 

During the flowering phase, we recommend you change the nutrient bath regularly. You can do this daily or at least once a week for the best growth. This is because the cannabis plant can get really hungry during this stage.

Growth Mediums

Deep water culture systems do well with growing mediums such as perlite, hydroton, coco coir, and Rockwool. You don’t need a lot of growing media, though — some hydroton in net pots placed on a growing tray will do the trick. The aerated nutrient solution would provide all the nutrition and oxygen.

Solution Aeration

In deep water culture, the cannabis roots benefit from a generous level of air bubbles. You can choose to go with low-cost pumps that only supply around 2 to 3literss of air per minute through the airstones if you only want a basic DWC setup. 

On the other hand, if you are serious about growing cannabis using DWC, we recommend you invest in high-end airstones and pumps to supply up to 20 to 30literss of air per minute to the roots. Such a significant air supply volume would encourage your plant to grow even faster. 

Temperature

Roots grow faster in higher temperatures but only up to a specific limit. However, there’s one risk with high temperatures — harmful bacteria, slime, and algae can grow in the solution and roots if the temperatures exceed 24 degrees Celsius. 

Our solution? Try to maintain a temperature of around 18-20°C for optimum growth and no risk of bacteria or algae.

Humidity

The humidity requirement for growing cannabis in deep water culture is also different from other growing methods. For your DWC cannabis setup, you must maintain the humidity at around 50% instead of over 70%, like you would with other systems.

This is because the buds get particularly heavy and oversized in this method, making them vulnerable to mold or bud rot with higher humidity levels. Thus, lower humidity is ideal for deep water culture cannabis plants.

Light

For any cannabis plant, whether you grow hydroponically or use soil, lighting is one of the most critical elements for healthy growth. Ideally, we recommend using high-pressure sodium (HPS) lights for growing cannabis. However, HPS lights also heat up a lot and consume a lot of energy. 

You can perhaps deal with the energy bills of using HPS, but your DWC cannabis plant may not handle the warm environment produced by HPS light. So, unless you have a sophisticated DWC system with precision cooling, we don’t recommend using HPS lights.

We recommend you use LED lights for the best growth for optimized light spectrum and reduced levels of heat stress.

Bucket

Deep water culture wouldn’t be the same without a deep bucket where the roots grow under an aerated nutrient solution. In fact, the deep bucket gives this system its name — deep water culture. 

Make sure you must use light-tight buckets — the bucket must not leak any light into the nutrient solution, so using black buckets will help. Avoid using white, cream, or opaque buckets as they leak light that further encourages the growth of algae and harmful bacteria within the solution.

Step-by-Step Guide to Growing Cannabis in Deep Water Culture

There are many variations to growing a DWC cannabis plant — from single-plant single bucket systems to multiple plants in a more sophisticated reservoir system. But for beginner DWC growers, we recommend using a single plant single bucket system. 

So let’s take a look at that.

Step 1: Germinate the Cannabis Seeds

The first step is to germinate the seeds. You can use Rockwool or peat pellets for germinating your seedlings.

Once the seedlings germinate, fill the net pots with some hydroton or perlite and place the seedlings in them. Then, you can set the net pot on the lid of your DWC bucket. 

Step 2: Set Up the DWC System

Now, it’s time to set up the DWC system. 

It’s best to begin with buckets that have lids. However, if you don’t have them, you can use a styrofoam sheet to function as a lid. Next, drill a hole on the bucket’s lid, just enough for the net pot to fit in. Drill a larger hole, and you risk letting the light pass into the nutrient solution.

Next, you have to place an air stone at the bottom of the bucket. You also may have to drill a hole at the bottom of the bucket to route the air pipe to the airstone. Lastly, you need to set up other devices like the lighting system and humidifier and calibrate the pH and EC meters.

Once all is ready, fill the bucket with the nutrient solution you’ve prepared for the plant. Again, remember to start with a weak solution. You can scale it up later as the plant grows. 

During this stage, the seedling’s root won’t be as long to reach the solution underneath. Therefore, we recommend you top-feed the seedling for the initial few days. Once the roots reach down to the solution in the bucket, they will grow independently.

Step 3: Taking Care During the Vegetative Stage

As your cannabis grows into a small plant, the roots will start to multiply. The solution may deplete because of the rapid root growth. Keep checking the solution daily and top-up or replace it regularly. We recommend you replace the solution at least once a week (and more, if you prefer).

If you notice any signs of nutrition deficiency, you can even add a more concentrated solution. You also need to keep checking the pH balance of the solution daily. If the pH is not between 5.5 to 6.5, replace the solution or adjust the pH.

Step 4: Training Your Cannabis Plant

Experienced growers train their plants to maximize yields. However, if you’re a beginner, you can start with basic methods. 

The first method of training your plant is bending it so that the top leaves don’t overshadow the lower leaves and stunt their growth. Here, use thin bamboo sticks to bend and tie your plant, so all plant parts get adequate light.

Next, you can use the SCROG method to train your cannabis plant. You can use a trellis frame of either thin pipes or threads to support the plant’s branches. We don’t recommend trimming the leaves, except dead or damaged ones. 

One of the best methods to train your cannabis plant is to use the LST or Low Stress Training method. However, it's best to Top the plants before you LST. 

Topping is another training method where you cut the tip of the plant, so the main cola divides into several colas. Again, the idea is to let the other parts of the plant get more light.

The basic idea behind LST is to train the plants so that all the plant parts uniformly get light. LST is easy if you are growing plants in soil. However, it could be a little tough to train the plants when you have no space to tie them to in a DWC bucket.

Growers use several methods to LST their plants in DWC. But, regardless of the technique you use, ensure you can easily lift the bucket's lid to change the reservoir solution later. Again, try not to drill the bucket with too many holes as it allows the light to enter the reservoir solution, creating too many issues.

One idea to LST while using DWC systems is to fasten bamboo poles horizontally to the bucket. Then, you can tie the branches to the pole as the plant grows. Do not use anything sharp to tie the plants as it might cut into the stem.

Another way to train the plants is to use an adjustable wire to hold the plants in place. Tie the wire to the plant’s stem and use clips to hold the branches in place as they grow. You can also find such wires sold as LST tools online. 

Finally, if nothing suits your fancy, you can use clips to bend the plants. Known as plant benders, there are many such clips available in the market. You can also use soft rubber bands to tighten the stems, so they don’t snap back into place. 

The method above illustrates how you grow plants in single DWC buckets; however, what if you wanted to grow more than a few plants using this method?

Well, it's pretty simple — instead of using one single bucket, you can use a styrofoam sheet to place the net pots. Or, you can use a big bucket and a lid that holds several net plots in place. The big bucket will act as a reservoir. 

Cannabis plants tend to use a lot of nutrient solution during the flowering stage. Therefore, make sure you get a bucket that holds at least 10 gallons if you plan to grow many plants in the same reservoir. In addition, as mentioned already, keep checking the nutrient solution frequently during the flowering stage, so you can top up as necessary. 

Many growers hesitate to use the DWC system because they worry that the plants can suffocate with too much water since their roots are submerged in water at all times. However, you don't have to worry about this if you provide adequate oxygen through an air pump. When the plants absorb the nutrient solution plus oxygen, they experience explosive growth.

Note that since the roots will be submerged in water at all times, it is important to keep the airstone and pump running 24/7 too. Failing to do this will kill the plants.

To set up a DWC system to grow many plants, you must follow a few steps.

First, germinate the seeds, as usual, using jiffy pellets or Rockwool cubes. Then, place the plants in net pots. 

Many growers use simple cups and drill holes at the bottom of the pots; however, it’s not necessary. Firstly, net pots aren’t costly, and the holes are there for a reason. They allow the roots to spread out from different areas and promote a healthy root system.

Next, place the air stone in the reservoir and connect it to the air pump. You can then set the net pots on a styrofoam sheet or drill holes in the reservoir’s lid. Do not drill too many holes as light may pass through into the nutrient solution. 

Lastly, make sure there is a lot of aeration for the plants to get all the oxygen they need. The more bubbles, the better.

Step 5: Handling the Bloom Stage

During the flowering stage, focusing on nutrient control is the key. Now, you must monitor the nutrient solution meticulously — multiple times a day. This is because the plant may use up the entire bucket of solution within a day to grow healthy buds!

Plus, the plant may not consume all the minerals at the same rate, leading to NPK imbalance or deficiency. Refresh the solution daily, but if it starts smelling after a while, you can consider adding anti-bacterial additives. 

Step 6: Harvesting the Cannabis Plant

If all goes to plan, you will see a generous yield of a few hundred grams per plant. 

The harvesting process isn’t different from other growing methods. Do remember to use gloves, though!

Summary: How To Grow Cannabis Plants In Deep Water Culture 

The deep water culture method is famous for its potential yields, and if it’s worth doing, do it well. Never cut corners. Read the signs your plant gives you when it’s growing. Understand the plant and optimize the environment and nutrient solution for optimum growth. 

There are two ways to grow cannabis using DWC — you can either build a basic setup at home or purchase a complete kit. The kits aren’t that expensive either, but make sure you get quality air pumps and buckets. Do not buy white buckets or anything that allows light to pass through. 

Do not hesitate to grow plants using the DWC method — they sound complicated, but it all becomes easy once you start. The first few tries may be intimidating, but you will get there with practice. 

If you decide to grow plants using the DWC method, follow the steps listed above and understand your plant’s needs, and you will have yields that would surprise you, even in your initial batches! There’s a reason why DWC-lovers wouldn’t grow their cannabis any other way.