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Types Of Hydroponic Systems For Cannabis

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JoshuaHolt JoshuaHolt
Added 11 January 2021
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Growing Cannabis In Hydroponics

Just starting out with cannabis cultivation or looking to explore hydroponics? This article teaches you about the various hydroponic systems on the market today and how you can get one up and running in your own home.

Hydroponics may seem like a challenge at first, but they are is actually very easy to set up. How you maintain your hydro system is another question and can hugely determine the success of your harvests. There are a few types of hydroponic system but the principal is more or less the same for each. The way the nutrients and oxygen are delivered to the roots is just slightly different.  Hydroponic systems remove many of the complications a grower has to face when growing with soil.

What is a Hydroponic System?

Cannabis Roots In Hydroponics

A hydroponic system is a growing setup that involves various pieces of equipment to circulate water and oxygen around the roots of a plant. The system does not involve the use of soil and tends to require an inert medium such as coco coir or clay pebbles in order to create a type of planting bed to support the growth of the plant above ground. Everything is connected to timers using air and water pumps so the plant can receive regular dry/wet cycles.

Different Types of Hydroponic Systems

It is possible to design your own hydroponic system at home, but if you are just starting out, we recommend purchasing a kit to avoid headaches later on. A failed system can instantly cut off the life blood of your cannabis plants, meaning they can die in a matter of days if the hydroponics system is not maintained correctly. A premade system makes setting up extremely simple and you can start the grow cycle confidently, knowing everything is working.

So, here are 6 hydroponic systems commonly found on the market today:

DWC (Deep Water Culture)

DWC (Deep Water Culture)

Deep water culture or DWC is a widely used hydroponic system amongst many hobbyist growers. In a DWC system, the roots are suspended in a reservoir filled with water or nutrient solution that is constantly oxygenated using an airstone connected to an air pump. The plants and roots are supported using small nets pots filled with a well aerated grow medium such as clay pebbles.

Depending on the design, the reservoir of a DWC system can either be set up with one or two nutrient tanks. This way a grower can mix nutrients in a separate tank without disturbing the roots.

In a single tank system, the reservoir sits below the plants and the roots dangle in the water for the duration of their life. Unlike other systems which use irrigation cycles on a timer, DWC simply requires you to fill up the reservoir and leave the air pump running, being sure to refill it as and when is necessary. DWC is one of the cheaper methods of using hydroponics and it ease of use makes it an attractive choice for many.

Cannabis Grown With DWC Hydroponics System

However, there are always downfalls to any design, so let's take a look at the pros and cons of DWC hydroponic systems:

Pros of DWC

  • Cheap and easy to set up. 
  • Does not require extra equipment such as a mechanical timer.
  • Ideal for beginners looking to try hydroponics.
  • Nutrient solution is simple to change.
  • Involves minimal maintenance compared to other systems.

Cons of DWC:

  • Air pump failure could mean disaster for your plants.
  • The reservoir is part of the system, making it very heavy and hard to move.
  • The reservoir can only be cleaned between grows.
  • Multiple airstones are needed to fairly distribute oxygen to each plant.
  • Constantly wet roots can create a higher risk of pests or mold

Ebb and Flow (Flood and Drain)

Ebb And Flow Hydroponics System

Ebb and flow, also referred to as 'flood and drain', is a bit more advanced than a DWC system in that it requires more equipment and relies on a timer to provide the roots with a wet and dry cycle.

A flood and drain system does as it says. The roots are flooded at intervals with water or a nutrient solution, which then drains out and back into the reservoir to be circulated through again when the next cycle is triggered. The amount of cycles each day depends on the climate and grow room conditions.

The reservoir is normally situated below the flooding tray to allow for easy drainage. A water pump (connected to a timer) is used to force the solution up from the reservoir into the flooding tray where the roots sit in pots filled with inert grow medium. Once the timer signals the pump to switch off, the roots are allowed to benefit from the oxygen that surrounds them until the pump turns on again.

Growing Cannabis With Ebb And Flow Hydroponics System

Pros of Ebb and Flow:

  • Provides good aeration to the roots.
  • Nutrient solution circulated regularly, preventing it from becoming stagnant.
  • Accurate control over irrigation and wet/dry cycles.
  • Kits are affordable and can deliver high yields with the correct usage.

Cons of Ebb and Flow:

  • May be complicated to set up for first timers.
  • Involves a number of parts such as submersible pumps and mechanical timers.
  • More parts means there is higher risk of system failure.
  • Requires some understanding of environmental control to get the cycles right.
  • Needs regular maintenance.

NFT (Nutrient Film Technique)

NFT System

The Nutrient Film Technique (NFT) system provides a balance between aeration and watering. A thin film of water or nutrient solution is allowed to wash over the ends of the roots, as the upper parts remain oxygenated by never being submerged.

An NFT system involves setting the up the planting bed or grow tray at a slight angle to create a constant stream. Water or nutrients are pumped up from the reservoir through the top of the planting bed, which then gently flows over the roots and drains out of the bottom end to be recirculated. An airstone is placed in the reservoir to oxygenate and stir the nutrient solution.

Introducing young plants into an NFT system usually requires the grower to top feed by hand or use a drip system first to give the main root enough time to reach the nutrient solution flowing through the system. It's common for the roots to grow so long they end up spreading across the bottom of the grow tank.

NFT (Nutrient Film Technique) Hydroponics System

Pros of NFT:

  • Helps to maintain a more stable pH due to its irrigation/aeration consistency.
  • Salt does not build up easily.
  • The roots can be easily inspected.
  • Makes efficient use of water and nutrients, wasting very little.
  • Lots of plants can be grown in one system and it is scalable, making it ideal for commercial sized grows.

Cons of NFT:

  • A failed piece of equipment can cause the plants to die in a matter of hours.
  • May not provide large plants with enough support.
  • Roots can grow long enough to affect other roots in the grow tray/gutter, clogging the system.
  • Not ideal for beginners of cannabis cultivation.

Wick System

Wick System

The wick system may not be the most efficient way to grow cannabis with hydroponics, but it certainly works and can produce great results for those on a budget looking to try their hand at growing using soilless methods. This system does not require pumps to deliver nutrients to the roots. Rather it achieves this through capillary action using a wick or rope.

A planting bed is built separately from a reservoir filled with a nutrient solution. Each plant sits in a pot that has a nylon rope running from the root zone to the reservoir. The containers are filled with a water absorbent grow medium such as coco coir mixed with perlite (to provide drainage and aeration).

Growing Cannabis Using The Wick System

Pros of the Wick System:

  • Does not fail easily as it is not reliant on pumps.
  • Requires very little maintenance.
  • Cheap and simple to use compared to other systems.
  • Feeds the plants at their own pace.

Cons of the Wick System

  • Limits the amount of water than can be delivered to the plants, making it unsuitable for larger plants that drink a lot.
  • Plants can grow slowly.
  • Nutrients are not circulated within the system, causing water to stagnate.
  • Prone to overwatering or the development of algae as the wick stays wet most of the time.

Drip System

The Drip System

The Drip System is a popular method of irrigating plants and is used across many large scale grows or farms. The principle is fairly straightforward and instead of the roots being fed from below, the nutrient solution is delivered to the top of the grow medium using a pump or a gravity system. 

Using flexible hoses and pipes with small drip holes, the nutrient solution can be delivered to each plant individually, with the possibility of connecting many plants to the same system. Depending on the system, single bucket reservoirs or gutters can be set up to collect the runoff for reuse. Drip systems can be either circulating or non circulating.

Growing Cannabis Using The Drip System

Pros of Drip Systems:

  • Provides excellent aeration, especially when used with expanded clay pebbles.
  • Each plant can be fed and controlled more accurately
  • Individual drip systems reduce the risk of pests or mold spreading.
  • Less technical equipment used to set it up.
  • Can be used for many type of plant.

Cons of Drip Systems:

  • pH fluctuations are common in drip systems and need regular checks.
  • Non circulating systems can be wasteful if the nutrients and irrigation are not managed correctly.
  • Drip system tubing can sometimes get clogged from salt building up when the system isn't circulating.
  • Needs thorough checks to make sure system is sealed.
  • Pump failure gone unnoticed could seriously affect plants, and possibly lead to death.

Aeroponics

Aeroponics System

Aeroponics is a type of hydroponics that uses misters to spray the roots with very fine droplets of pressurized, fertilized water. Normally the reservoir is part of the grow tank, and the roots hang above the surface of the water or nutrient solution.  

There are two types of aeroponic system; one design uses a high pressure (HP) system and the other a low pressure (LP) system. High pressure systems are better suited for cultivation and tend to deliver a finer mist

Using a high pressure submersible pump and special misting nozzles connected to a timer, the roots can receive plenty of oxygen, water and nutrients as the inside of the tank is misted for short periods of time, but frequently. The excess moisture drains off the roots and back into the reservoir below to be recycled.

Growing Cannabis In Aeroponics

Pros of Aeroponics:

  • Saves a ton of water and nutrients.
  • Provides optimal aeration to the roots.
  • Can deliver higher yields compared to other hydroponic growing techniques.
  • Good for building vertical gardens.
  • Diseases do not spread quickly as plants are normally in their own individual system.

Cons of Aeroponics:

  • Difficult to maintain and keep the conditions inside the growing tank stable.
  • Pumps and other equipment for aeroponics can get expensive and need regular cleaning to prevent blockages.
  • Roots can dry extremely quickly if the misters or pump fail.
  • Each plant requires more space as the tank needs to be large enough give the roots enough room to be misted efficiently.

Choosing The Right Grow Medium

Grow Medium For Hydroponics

Most hydroponic systems use an inert material not only to support the roots, but provide them with a way to stay well hydrated and oxygenated between feedings. There are numerous grow mediums used for hydroponic systems, each with slightly different properties and functions.

Clay PebblesClay pebbles, often referred to as expanded clay, are highly recommended for most hydroponic systems since they provide extremely efficient aeration and retain enough moisture to keep the roots well hydrated at the same time.
Rockwool This inorganic, fibrous material can be seen being used in cannabis cultivation often and is similar to fibreglass, but made from minerals/rock. It's known for its ability to retain water and air, and can deliver nutrients efficiently to a cannabis plant's roots.
Perlite Perlite is made from volcanic rock and is used for its high permeability and aeration properties. Perlite is generally used as a soil amendment but it also works well in hydroponics, especially with coco coir to prevent it from compacting.
Coco CoirCoir is ground fibres from the husks of coconuts and has become very well suited to hydroponics systems for being similar to soil but without the life in it. Coco coir is organic, has a neutral pH, and holds moisture efficiently, making it a great home for roots. Not ideal for systems that use net pots, where there is a risk of the grow medium filtering into the reservoir, which could cause blockages.

Choose a grow medium to suit your hydroponic system and be aware of how easily it may filter through. You want to avoid the grow medium falling through and clogging up the system.

Tip: Make sure your grow medium has been pH adjusted before introducing your plants to it.

Maintaining A Hydroponic System

Maintaining your hydroponic system is the key to success. Hydroponic systems are great for introducing automation into your grow practice, but they still require plenty of attention to keep them running smoothly.

  • Try to keep the system circulating as often as possible to avoid salt build up.
  • It is best to water less but more frequently.
  • Maintain the temperatures in the reservoir between 21-23°C.
  • Use airstones in your the reservoir wherever possible to help prevent stagnation.
  • Thoroughly clean/sterilise all pipes, tubes, containers, nets, and pumps between grows.
  • Adjust your timers to provide the perfect wet/dry cycles.
  • Use nutrients designed for hydroponics and avoid organic materials that could clog up the system.
  • Place your hydroponic system on a raised platform or table for easier drainage and maintenance.
  • Have spare parts or backup equipment in case of sudden failure.
  • Check your hydroponic system daily.

The more you practice using a hydroponic system, the better you will get at growing with it. Make adjustments to suit your cannabis plants' needs and the yields can be highly rewarding. A hydroponic system definitely requires more attention than a soil/potted plant, so keep in mind how often you will need to visit the grow room to make sure everything is in order.

GrowDiaries user NuggetPawn's hydroponic setup.

Have you grown using hydroponics? Which system worked best for you? If you found this article useful, please feel free to leave a comment for fellow growers down in the comments section!

External References

Nutrient Management in Recirculating Hydroponic Culture. - B. Bugbee (2004).

The results of an experimental indoor hydroponic Cannabis growing study, using the 'Screen of Green' (ScrOG) method-Yield, tetrahydrocannabinol (THC) and DNA analysis. - Knight, Glenys & Hansen, Sean & Connor, Mark & Poulsen, Helen & McGovern, Catherine & Stacey, Janet. (2010).

Comparing hydroponic and aquaponic rootzones on the growth of two drug- type Cannabis sativa L. cultivars during the flowering stage. - Yep, Brandon & Gale, Nigel & Zheng, Youbin. (2020).

Hydroponics Cultivation of Crops. - Gaikwad, Dinkar & Maitra, Sagar. (2020).

Hydroponics Cultivation Cannabis sativa L. Plants. Planta Medica - PLANTA MED. - Chandra, Suman & Lata, Hemant & Khan, Imtaz & Elsohly, Mahmoud. (2010).

Interactions between growing media and biocontrol agents in closed hydroponic systems. - Khalil, Shahid & Hultberg, Malin & Alsanius, Beatrix. (2011).

Hydroponic Growth Media (Substrate): A Review. International Research Journal of Pure and Applied Chemistry. - Patil, S. T. Patil & Kadam, U. & Mane, M. & Mahale, D. & Dhekale, Janardan. (2020).

This article was updated December 2020.






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