Welcome to my hydroponic weed growing guide where I overview the different type of hydroponic growing options and resources to successfully grow cannabis without soil.
Hydroponics are the practice of growing cannabis plants using one of many non-soil systems. Hydroponic weed systems can be more complex to set up, but growers choose this method because it offers faster growth and higher potency cannabis when done correctly.
Is Hydroponic Grown Cannabis Better?
Growing weed via hydroponics can result in higher potency and faster plant growth than cannabis grown in soil, although it requires a bit more maintenance.
The reason hydroponically grown weed is better is due to the increased nutrient and oxygen exposure compared to cannabis grown in soil.
The Different Types of Hydroponic Growing Systems:
The term hydroponics can refer to any method of non-soil weed growing system. The different types of hydroponic growing systems are:
- Bubbleponics / Deep Water Culture (DWC)
- Ebb and Flow
- Nutrient Film (NFT)
- Drip systems
Some of the popular soil-less growing mediums used in hydroponic systems are:
- Open Air
- Coco Coir
- Clay Pebbles
- Peat Moss
Hydroponic growing methods vary slightly, but instead of being buried in a pile of dirt to absorb nutrients and oxygen that happen to be in the vicinity, hydroponic growing techniques tend to give roots more direct exposure to nutrients, water and oxygen with the hopes of growing plants faster and larger.
This is how each hydroponic growing system ranks in terms of usability for growing cannabis:
1. Bubbleponics / Deep Water Culture (DWC) – Best all around, suitable for large plants – complete systems for all size plants available.
2. Aeroponics – Second best – A little harder to find a system for large plants – complete systems for clones are readily available. Likely have to DIY a system for larger plants (see video below).
3. Ebb and Flow – A bit more complicated – A bit more expensive – Can be good if done right – Systems available for all size plants.
4. Drip Irrigation – Simple – easy to run – Drip systems available for all size plants.
5. Nutrient Film Technique (NFT) – Another complicated setup – geared towards small/medium plants, clones – NFT systems available here.
Bubbleponics / Deep Water Culture (DWC) – Best All Around Hydroponic Method
The deep water culture (DWC) method is when the plant roots are fully submersed in nutrient water. Air stones in the grow bucket reservoir are constantly oxygenating the water for the plants to use.
Deep water culture (DWC) is a pretty popular method with weed growers. There are DWC kits readily available for sale that are very close to plug and play.
As you can see in the image above, most deep water culture kits are a bucket design with a net pot in the center where you place your seedling. Inside the bucket you have the nutrient water reservoir, air stones, and a pump usually on the outside.
Benefits of DWC cannabis:
The benefits to growing cannabis via deep water culture are:
- Plants have easier access to all the oxygen and nutrients they need via the roots sitting in the water.
- Done right you should experience faster more robust growth than growing in soil.
- Some people claim potency is higher with hydroponics grown weed.
Drawbacks of DWC cannabis:
The main downside to deep water culture weed is when you initially plant your seedling into the center of the DWC net pot, it can take a while for the roots to reach the nutrient water below.
There are two ways of dealing with this: first is to keep the roots hydrated until they reach the water (you don’t have much of a choice, actually). The second solution is just get a bubbleponics setup instead.
DWC vs Bubbleponics (recirculating drip):
The difference between DWC and bubbleponics is one simple feature to address the initial stage when the seedling roots haven’t reached the nutrient reservoir yet.
For most growers this initial phase of deep water culture can be a hassle because you have to manually keep the roots moist until they grow into the reservoir.
Bubbleponics setups include a water line that runs from the reservoir into the net pot grow cup area of your DWC setup where your seedling resides.
This modification became known as “bubbleponics,” or the more proper “recirculating drip.” This modification considerably accelerates the growth of seedlings in the first few weeks. That’s because the constant drip is feeding the seedling roots when they’re still above the main reservoir.
The bubbleponics variation of growing is a lot more effective than manually keeping the rockwool/roots moist until they grow down into the nutrient water reservoir.
Once the roots reach the water, the recirculating drip feature doesn’t make a difference. But the bubbleponics method is still significant enough to have its own place in indoor growing.
Compared to deep water culture, I’d think most growers would prefer bubbleponics since these setups are very reasonably priced and that one additional water line to the net pot offers a lot of convenience.
One of the great things about the system above is that it’s close to plug and play.
Don’t sleep on the deep water culture or bubbleponics growing methods. Take a look at the monsterous DWC cannabis plant pictured at the top of this section. You can pull that off too when you follow the proper steps.
Required DWC Growing Maintenance:
Even if you’re growing in soil there’s some degree of maintenance involved with watering and pruning. When you’re growing cannabis with deep water culture or bubbleponics, there are a few things you’ll occasionally need to check up on.
- Water temperature – You’ll need to keep water temps around 75 degrees fahrenheit (24 celsius). Warm water encourages bacteria and root rot. If your setup has a pump that’s located inside the nutrient reservoir, the pump can really heat up the water if it malfunctions. High room temperatures will also affect your reservoir temperature. This all-in-one meter is great for monitoring temperature, dissolved solids (TDS), Electrical Conductivity, and pH in 5 seconds flat.
- Sealed reservoir – Not really maintenance, but make sure your reservoir is sealed so no light gets inside – light will encourage root rot. Fill any empty grow cups (net pots) on top of your unit with rockwool or clay pellets to block out light.
- Root rot – You can prevent root rot with Hydroguard. A popular root protectant used by hydroponic growers. Doesn’t change water pH.
- pH balanced reservoir – As your plant roots absorb nutrients and grow, the pH of the reservoir will gradually change, so you’ll need to monitor it regularly. You can make sure your reservoir is pH controlled with this very affordable General Hydroponics pH control kit. Nutrients like the popular General Hydroponics nutrients already come pH balanced.
Growing Cannabis with Aeroponics (Most efficient):
The aeroponic method may be the most efficient method of growing cannabis. This involves allowing the cannabis plant roots to grow into an enclosed space where the roots are continuously misted with nutrient rich water.
Benefits of using Aeroponics to Grow Cannabis:
Aeroponic growers point out the many benefits of this system, which include:
- Increased root oxygen exposure,
- Limited susceptibility to disease due to separation of plants and lack of soil,
- Considerably faster growth rate.
So how does aeroponics work? You take a seedling, still inside a moistened rockwool cube, and place it in the planter cup (net pot) on your setup. The planter cup has open holes on the bottom for the roots to grow through and access the nutrient mist. The mist is continuously sprayed from the reservoir into the air surrounding the roots.
That’s pretty much it. A majority of the labor involved with Aeroponics is setting up your system and occasional maintenance which I describe more below.
Drawbacks of Aeroponic Grown Cannabis:
While aeroponics can be considered the most efficient method for growing plants, there are still some drawbacks to be considered:
Limited number of cannabis aeroponics systems:
For people growing weed specifically, there aren’t many aeroponic setups tailored specifically to growing full size cannabis plants. Many growers use aeroponics to grow clones because the available products are better suited for smaller plants.
Below I list two setups I found – one for full size plants and one for clones.
Because of this, many people choose to DIY their own cannabis aeroponic systems. Check out the DIY aeroponic video just below to get an idea of what you’ll need.
Aeroponic Cannabis System Maintenance:
Another drawback is aeroponic growing requires a bit of maintenance.
Spray nozzles tend to clog – Luckily there’s a cheap and easy fix. Get an extra set of nozzles on Amazon and soak one set while the other set is operational.
pH balanced reservoir – The mist needs to have a pH level of 5.5 to 6.5. You can make sure your reservoir is pH controlled with this very affordable General Hydroponics pH control kit. Nutrients like the popular General Hydroponics nutrients already come pH balanced but make sure your water is also balanced.
If you want to grow a large weed plant using aeroponics, you can consider making a DIY setup, which many claim isn’t that hard. Check out the DIY aeroponic video just below to get an idea of what you’ll need.
Growing Cannabis with Deep Water Culture (DWC) vs Aeroponics:
In 1991 scientists at the University of California ran a study comparing plant roots grown in fully submerged nutrient water, using only a nutrient mist, and in an un-misted environment.
Soffer and Burger [Soffer et al., 1991] found that the number and length of roots grown using nutrient mist were the greatest compared to the fully submersed roots and (obviously) completely unexposed roots.¹
Even though aeroponics was found to grow better plants, is the difference between DWC and aeroponics huge? Likely not. For that reason I believe the best all around hydroponic weed system is deep water culture / bubbleponics.
Growing Cannabis with an Ebb and Flow System:
Ebb and Flow systems work by periodically flooding the grow tray with nutrient water, soaking the roots and allowing them to abosorb what they need. The grow tray drains within 30 minutes and your plants are good for a couple hours until the next flood.
How and when to flood your cannabis plants using ebb and flow:
Ideally you’ll be flooding your plants for 30 minutes total, and between 2-4 times daily. There are some factors to be considered to determine whether you should flood 2, 3, or 4 times.
The first factor is the growing environment. Cooler environments can be flooded less often – two or three times daily. Hotter environments can make use of an extra flood.
The second factor is your grow medium. If your grow medium retains moisture well, like rockwool, you won’t need to be flooding the plants four times daily. Grow mediums that drain quickly like clay pellets can probably use an extra flood, especially in hot environments.
No matter how many times you decide to flood, make sure only to do so when the plant is awake (grow lights turned on). Don’t flood plants while they’re in a dark resting period.
Determining how many times to flood your plants is more of an art than a science. Watch how your plants react and adjust based on that.
Once you’ve got the flooding down pat, there isn’t much more to this system than regular maintenance of checking pH, temperature, and solids.
These pre-assembled Ebb and Flow kits cut down the setup time and allow you to focus on other things.
Growing Cannabis via Continuous Flow Systems (Drip & NFT):
The next two hydroponic systems you can use to grow weed are Drip Irrigation and Nutrient Film Technique (NFT). These are both known as continuous flow methods because you more or less have nutrient water flowing continuously.
Drip Irrigation Systems:
Drip systems are top feeding systems that can be used with hydroponic mediums or soil. Water is pumped up from the reservoir and slowly dripped through the growing medium, keeping your plants fed at all times.
Benefits of Drip Irrigation
- More efficient water use.
- Pre-assembled drip systems are plug and play.
- Less frequent maintenance compared to other hydro methods.
Drawbacks of Drip Irrigation
- Risk overfeeding – If your drip irrigation system is watering too often or too much, you’ll risk overwatering your cannabis. The drip frequency will also need to be adjusted as the plant matures and requires more nutrients.
- Less root oxygen exposure compared to aeroponics and bubbleponics.
Overall, pre-assembled drip irrigation systems may be the easiest hydroponic setup for new or less experienced weed growers.
You can get some awesome plug and play drip irrigation kits at LED Grow Lights Depot. They have kits for all budgets, and all plant sizes.
Growing Cannabis via Nutrient Film Technique – A Complex Method:
Nutrient Film Technique (NFT) hydroponic systems are another example of continuous flow hydroponic systems. These systems are popular with large commercial grows of small-medium size plants , but they can scale down in size to a single row of plants.
Nutrient water is continuously pumped from a reservoir through a slightly sloped tray of plants whose roots are exposed partially to the constant flow of water. The remaining section of the roots are suspended in oxygen between the grow cup and the tray floor where water is flowing. Excess water drains back into the reservoir.
In comparison to previous hydroponic weed growing methods detailed above, the nutrient film technique system is more complex, and thus more risky and a less attractive option for growing weed.
One factor that needs to be considered if you go this route is the gradient (slope) of the growing trays. It’s generally recommended to use a 1% slope, but you may need to increase up to 3 or 4%. The whole point of the slope is to keep the flowing water from gathering and forming a motionless pool inside the tray, which can lead to root rot.
Another factor is the rate of water flow through your trays. Some growers have recommended finding a happy medium between 1 and 2 liters per minute. Obviously make sure the water is draining fast enough to keep up with the flow.
Benefits of Nutrient Film Technique (NFT) hydroponic systems:
- Root oxygen exposure
- Efficient water use
- Good design for growing multiple seedlings/clones at once
Downfalls of Nutrient Film Technique (NFT) hydroponic systems:
- Pre-assembled kits are pricey, and better suited for small to medium size plants
- More complex to operate – You need to find the right level of water flow, and the right gradient to slope the trays at. Adding/removing plants may necessitate adjusting the water flow.
- Generally take up more space than other hydroponic growing methods.
- Need to manually water plants until roots reach tray floor where nutrient water is flowing.
How does Nutrient Film Technique (NFT) compare to other hydroponic weed growing methods?
Compared to the other hydroponic weed growing methods discussed here, NFT leans towards the more complicated side. Not only that, but NFT is generally geared towards smaller sized plants – not great for cannabis unless you’re keeping clones.
If you decide to go the NFT route however, there are some nice NFT systems available here, and they’ll make the process a lot simpler for you.
What are the best nutrients for hydroponic cannabis?
General Hydroponics makes one of the most popular hydroponic weed nutrient kits around.
If you’re interested in secondary nutrients, there’s another brand called My Weed Minerals. My Weed Minerals are completely organic, and provide 62 divalent ionic minerals that activate your plant’s genetics during late stage growth in order to produce larger buds and tops. These minerals are derived from ocean water, but don’t worry, the salt is completely filtered.
Hydroponic Growing Supplies You’ll Need:
No matter which hydroponic weed system you choose, you’ll likely need these supplies to get the job done:
- Feminized seeds: I recommend ILoveGrowingMarijuana seeds as they’re guaranteed feminized, offer all different varieties (autoflowers, high THC, high CBD), worldwide shipping, and fairly priced.
- Hydroton Clay Pebbles – hydroponic growing medium used to fill grow cups on your setup where you place your plants.
- Rockwool Cubes – Start your seeds in these and seamlessly drop them into your hydroponic setup, surround them with larger rockwool, clay pebbles or other medium.
- General Hydroponics Nutrients – Proven for all growing mediums including Aeroponics, very popular nutrients with growers.
- Make sure your pH , total dissolved solids (TDS), electrical conductivity (EC), and water temperature are correct in 5 seconds flat with this highly rated all-in-one meter.
- An Analog timer to set your water pump operating intervals.
- A Digital Hygrometer to monitor your temperatures and humidity levels
- An oscillating fan to prevent mold spores from taking root in your grow space.
In summary, find a kit that’s right for your situation. If I had to pick, the best hydroponics kits for growing weed are probably DWC/Bubbleponics or a drip irrigation system. Aeroponics gets an honorable mention if you can DIY a kit able to grow a large plant.
What are the easiest hydroponic methods for growing cannabis?
The easiest methods for growing cannabis hydroponically are Deep Water Culture and Bubbleponics.
What is the most effective hydroponic method for growing cannabis?
The most effective method of growing cannabis hydroponically is aeroponics.
Why do people grow weed hydroponically?
People grow weed hydroponically because it may result in higher concentrations of THC as well as higher yielding plants.
What are the downfalls of growing weed hydroponically?
Hydroponic growing methods generally require more maintenance than growing cannabis in soil. Some growers also claim soil grown cannabis has better flavors, but flavor is a personal preference.
What is Deep Water Culture for cannabis?
Deep water culture is a hydroponic method of growing cannabis where a seedling is placed in a grow cup above a nutrient water reservoir. The roots grow into the reservoir instead of into soil.
What is Bubbleponics for cannabis?
Bubbleponics are a form of deep water culture hydroponic cannabis growing techniques where a recirculating drip is used to keep seedling roots moist until they grow into the nutrient water reservoir below.
What is Aeroponics for cannabis?
Growing cannabis with an aeroponic system suspends the plant roots in air while a pump continuously mists the roots with nutrient rich water.
What is ebb and flow for cannabis?
Growing cannabis with Ebb and Flow works by periodically flooding the grow tray underneath plant cups with nutrient water. The cannabis roots get soaked and abosorb what they need. This process repeats multiple times per day.
What are continuous flow systems for growing cannabis?
Growers use continuous flow systems such as drip irrigation and nutrient film technique, where roots are continuously exposed to nutrient rich water, instead of being fed periodically.
- Soffer, H., Burger, D. and Lieth, J. (1991). Plant growth and development of Chrysanthemum and Ficus in aero-hydroponics: response to low dissolved oxygen concentrations. Scientia Horticulturae, 45(3-4), pp.287-294.
- Chandra, Suman, Hemant Lata, Ikhlas Khan, and Mahmoud Elsohly. “Photosynthetic response of Cannabis sativa L. to variations in photosynthetic photon flux densities, temperature and CO2 conditions.” Physiology and Molecular Biology of Plants 14.4 (2009): 299-306.
- Backer Rachel, Schwinghamer Timothy, Rosenbaum Phillip, McCarty Vincent, Eichhorn Bilodeau Samuel, Lyu Dongmei, Ahmed Md Bulbul, Robinson George, Lefsrud Mark, Wilkins Olivia, Smith Donald L. (2019). “Plant Growth-Promoting Rhizobacteria for Cannabis Production: Yield, Cannabinoid Profile and Disease Resistance.” Frontiers in Plant Science 10. 10.3389/fpls.2019.00495