Growing Cannabis In An Aeroponics System

Through your cannabis cultivation endeavours you might have heard about aeroponics and be wondering how it works. Considered as an advanced hydroponics system by many, it could be said that aeroponics is in a league of its own. Now widely used in industrial farming, aeroponics has proven to be an extremely effective method for growing plants.

Setting up an aeroponics system may sound complicated to someone who has never used hydroponics before, however the concept is relatively simple. We want to show how it works to teach you the difficulties behind preparing and maintaining a fully functioning aeroponics grow. This step by step guide has all the information you need to get started.

What is Aeroponics?

Aeroponics is essentially a type of hydroponics. The major difference is how water and nutrients are delivered to the roots. In an aeroponic system, roots are suspended in air and frequently misted with oxygenated water and nutrients. In a hydroponics system, roots are intermittently flooded or submerged which means the solution and roots come into direct contact.

An aeroponics system also uses no growing medium to support plants. Instead, plants sit in small, net baskets spread across a planting bed with a draining system for roots. The water/nutrient solution is usually stored in the reservoir below and circulates through the system via a pump and misting nozzles. Excess water drains and is collected in the reservoir.

Some aeroponics systems use two reservoirs: one for collecting drainage, and another for supplying fresh nutrients. 

The Pros and Cons of Aeroponics Systems

Growing cannabis in aeroponics has huge benefits for the commercial grower. Hydroponics has taught us a lot about the advantages of using soilless mediums to produce large crops in a clean, controlled environment. Aeroponics takes this to another level, providing us with an even more efficient method that saves tonnes of water. Aeroponics can be a bit of a challenge to manage, but it is worth every penny.

Let's take a look at some of the reasons why you might consider installing an aeroponics system in your grow room.

Pros of an Aeroponics System

• Less Risk of Pests - Since aeroponics systems use no growing medium, plants live in a much cleaner environment which massively reduces the risk of pests.
• Oxygenated Roots - Roots receive a constant supply of oxygen so there is no need to use air pumps or air stones.
• Less Water Usage - Plants make efficient use of the available water and waste very little, making aeroponics more environmentally friendly than other hydroponics techniques.
• Full Control - pH balanced water and nutrients can be given in a fully controlled manner to support growth and bud production.
• Vigorous Growth and Yields - Aeroponics done correctly means rapid growth as well as humungous harvests.

Unfortunately it's not all sunshine and rainbows, and it should be noted that setting up an aeroponics grow is recommended for experienced growers who already have some knowledge about cultivation and hydroponics. Doing some prior research on your water quality, pumps and other equipment will help you avoid problems down the line. If you are planning to buy an aeroponics system, try to aim for the highest quality you can afford.

Cons of an Aeroponics System

• Expensive - Equipment and maintenance can be costly. Extra investments are necessary for cannabis to benefit from an aeroponics system, such as lighting, ventilation, pH and EC meters, or nutrients.
• Requires Maintenance - To avoid failure, an aeroponics system needs to be monitored as often as possible. You should be checking pumps, timers and nozzles regularly for blockages or other faults. 
• Difficult for Beginners - Having too much to manage can lead to mistakes, so using aeroponics is not advised for first time growers. More equipment means a higher chance of something going wrong. 
• Failure Can Kill Plants - Roots are very sensitive and if an aeroponics system fails, it can be fatal for a cannabis plant. A failed system will likely cut off circulation to roots, resulting in disaster very quickly.

Setting Up An Aeroponics System

Setting up aeroponics depends on whether you choose to purchase a system or build it yourself. Depending on your budget you may decide to keep costs down by buying the necessary parts. Making your own system can be beneficial in the sense that it can be adapted to fit your available grow space for maximum efficiency.

Although building your own system sounds like a good idea, it needs to be done properly to successfully grow. Any light leaks or water escaping need to be completely prevented so if you are just starting out it might be easier and safer to go for a store bought system.

The 2 main types of aeroponics either work with high or low pressure irrigation. High pressure (HP) systems spray roots with finer droplets of water using a special pump and often have a separate reservoir where water/nutrients are stored. Low pressure (LP) systems mist with larger droplets which usually drain straight back into a reservoir below the roots. Home growers tend to work with HP aeroponics for its efficiency.

A fully functioning aeroponics system requires the 6 following things:

1. Reservoir - A container where the water and nutrient solution are stored. The reservoir can either be part of the growing chamber or separate. Roots should not be sitting in the water, meaning the container has to be tall enough. This is especially important if the water isn't draining out into a separate reservoir.
2. Submergible Pump - Used to circulate the water between the reservoir and misting nozzles. Choose a reliable pump with a minimum of circulation rate of 200 - 300GHP (gallons per hour) and have a backup just in case. The higher the value, the more pressure misters can work with. Keep in mind that more misters decreases pump pressure. The efficiency also depends on how high up your misters are in relation to the pump.
3. Planting Bed - This is where the net pots sit for plants to hang in the reservoir. Acting as a lid for the reservoir, the planting bed keeps light out and provides the space for net pots to sit in. It also serves as a drainage mechanism and stops plants from getting wet during misting. Holes are made to keep net pots snug and secure in their position.
4. Spray Nozzles - These act like small sprinklers for the roots. The power of your pump and the quality of the misters will determine how effectively roots are watered. The smaller the droplet the better, so we recommend nozzles that spray at a droplet size of 20 - 50 microns. If the droplet is too large it may limit oxygen uptake through the roots.
5. Timer - Pumps can be set to run for 30 minutes, then stay off for 30 minutes. Shorter time frames are possible but too short and plants can show symptoms of overwatering. Timers can be adjusted to fit your plant's drinking needs but roots should never be left for more than an hour without watering. The cycle you choose can be followed throughout the whole grow.
6. Net Pots (with lids) - The net pots are where the root zone is separated from above 'ground' level. These small containers are fixed in place (to the planting bed) and have lids to protect each side of the planting bed. Usually cannabis will be germinated in a starter medium like jiffy pellets, rockwool or rapid rooters before transplanting into a net pot.

Growing Cannabis In Aeroponics: Tips

Growing cannabis in aeroponics isn't just as simple as putting the equipment together. Once up and running, an aeroponics system requires your full attention if you are looking to produce successful yields. Like hydroponics, you are in charge of all the nutrients and water, as well as the lighting, temperature, humidity and the system itself.

Measure pH and EC - This cannot be stressed enough. Fluctuations in pH and EC are common in aeroponics so your solution needs to be measured at least once per day. Roots are highly sensitive and absorb nutrients faster in an aeroponics system, meaning deficiencies can develop quickly if pH and EC are outside the comfortable range. The required pH of water or a nutrient solution in aeroponics is between 5.5 and 6.5.

Temperature - The best temperature for roots in aeroponics is between 18 - 24°C. Pumps can produce heat which may warm up water temperatures to a dangerous level, increasing the risk of harmful bacteria. Consider installing a water cooler if water temperatures are too high. On the other hand, if temperatures are too low, water heaters are a good idea. Make sure to use a high quality pump that produces low heat.

Nutrients - Most liquid hydroponics nutrients can be used for an aeroponic system. Start feeding small quantities to plants and work your way up. Less is more in this case. Salt build up is also more of a risk when nutrient concentrations are high. Some nutrients will get used up faster than others, which is why we suggest taking regular EC readings. If the reading is substantially lower than when you add nutrients, plants likely need a larger dose. If the reading is higher, then the concentration could be too high.

Aeroponics System by Zerobane from GrowDiaries

Grow Lights - Lighting has a big impact on a cannabis plant's environment so it is important to choose lights that do not produce too much heat. Due to the nature of the aeroponic system it is worth using cool lights in your grow room to keep temperatures in the reservoir down. LEDs are a wise choice for growers interested in growing with aeroponics for their low heat output, easy set up and efficient energy usage.

Cloning - Aeroponics systems are very well suited to cloning. Clones need an extremely sterile environment to root in as well as high humidity and plenty of oxygen. There are a number of systems available on the market today specifically designed for cloning that produce great results if they are well maintained.

The following data can be used to get a rough idea of the pH and EC levels suited to growing cannabis in aeroponics. Make sure to test the electrical conductivity of your tap water before and after adding nutrients. 

Tip: When roots are being misted they do not like to be drenched in water.  Nozzles can be directed so that misting happens around the roots, preventing delicate capillary hairs getting damaged.

How to Maintain Your Aeroponics System

To save you some hassle, it is very important that your aeroponics system is adequately maintained so it runs smoothly at all times. One slip up could cost you the whole process. Most of the maintenance required by an aeroponics system involves you being as hygienic as possible.

The first advice is to take the time to check and clean the whole system regularly. You need to be sure that pumps, tubing and nozzles won't get clogged when you are not there to monitor plants. It is difficult to watch your system 24/7, but make the effort to frequently check that it is functioning correctly. The reservoir should be cleaned and refilled with a clean solution every 7 - 14 days.

To keep your system clean during the grow, you can use hydrogen peroxide (H202) or certain enzyme products like Hygrozyme in your nutrient solution or between feedings. Just make sure you use the right concentration of supplements like hydrogen peroxide because it can burn your roots if it is too strong. Hydrogen peroxide sterilizes, meaning it will kill both good and bad bacteria.

Adding beneficial bacteria and fungi to your system can help to prevent harmful infestations ever being a problem, while protecting and strengthening roots. Keeping the right temperatures is critical to avoid bad bacteria or fungi developing. The main disease that you need to watch out for in aeroponics is the dreaded pythium, which we discuss below.

Tip: Do not expose roots/reservoir to light, which increases the risk of algae developing around the roots.

Moby Dick, Wappa, WW Aeroponics

Problems/Solutions

In the event of a problem, be ready to fix things as quickly as possible. Keep a strict monitoring schedule and have spare parts or backup equipment if you need to replace parts quickly. Some growers will even set up an emergency pump that triggers if the main pump fails. 

Power Failures - An aeroponics system relies heavily on electricity to power the pump. Power failures do happen and they are often out of your control but being ready means nutrients won't get cut off from your plant. 

Solution: Have a spare battery on hand. This can be set to switch on automatically just in case you experience a power cut.

Clogged Nozzles - Over time, minerals and salts build up in the misters causing them to become blocked. This is especially problematic between grows when the equipment dries out.

Solution: Clean all parts right after harvesting before salts build up. Flush system between cycles using 35% hydrogen peroxide diluted in warm water. Do a final flush with clean water before using the system again.

Pythium - A form of root rot that is very hard to get rid of once it has infected a water supply. Roots become smelly and discoloured, turning brown and slimy. It is often caused by overwatering and high temperatures, combined with the high humidity levels present in an aeroponics system.

Solution: Consider discarding plants and starting again with a fresh, sterile system. Treatment can be performed using 35% food grade hydrogen peroxide diluted to 3% by adding 11 parts of water to 1 part peroxide. 3ml per litre of water using 3% H202 is enough to treat pythium but won't eradicate it completely.

Conclusion

It is understandable that aeroponics may seem like an expensive option to grow cannabis, however the results more than make up for it. There are many different ways you can set up an aeroponics system so it is about finding what works for you and your plants. Getting the technique right takes time and dedication but you will be glad you spent the hours creating the perfect system.

Have you had any issues with aeroponics? Aeroponics is definitely worth talking about so if you found this useful or have any experience using aeroponics, feel free to share your tips in the comments section below.

External References

Getting to the roots of aeroponic indoor farming. New Phytologist. - Eldridge, Bethany & Manzoni, Lillian & Graham, Calum & Rodgers, Billy & Farmer, Jack & Dodd, Antony. (2020)

Pythium. - Sankaranarayanan, A. & Amaresan, Natarajan. (2020)

Measurement and Controlling of pH and TDS in Automated Hydroponics System. - Devvrat, & Ratan, Rajeev. (2019)

This article was updated September 2020