Hydroponic systems for growing weed are becoming more and more popular, and have started to overtake the traditional soil growing method. At first, hydroponic systems may seem a bit daunting, but with this guide, we will share all our knowledge on the topic so that you can make an informed decision regarding your grow system. It will take a couple of tries to make the transition, but once you get the hang of it your cannabis plants will be sprouting bug buds in no time!
Marijuana Hydroponic Systems: The Basics
Tip: practice growing tomatoes hydroponically first, as they grow very similarly to cannabis. This way you can make all your initial mistakes on a cheaper crop.
First of all, what is hydroponics? It is a method of growing plants without soil, instead using soluble minerals and nutrients to feed the plants. With some systems the plants are continually exposed to the solution, with other methods they are exposed periodically.
Hydroponic systems also keep the roots better aerated by providing them with dissolved oxygen. With the roots of the plant getting all the nutrients they need, the plant can use its food and energy to grow more buds, rather than growing their roots in search of nutrients.
What you need to grow weed hydroponically
Firstly, you need enough space to plant your marijuana plant. This could be in a grow room or tent, or somewhere in your home that can house a fully grown marijuana plant. You will need pots to put the plants in, as well as a grow medium (which replaces traditional soil) like coco coir or peat.
Next you will need an indoor grow light and plant food (i.e. nutrients) to provide the plant with all its energy sources in order to help it grow. If your grow light runs hot, then you will also need some kind of ventilation to prevent your plant and hydroponic system from drying out.
PPM testers for nutrient levels and pH testers for acidity are important for keeping your plant in optimum growing conditions. Finally, you will need the marijuana seeds or clones and you’re all set to begin growing!
Different Types of Growing Mediums
Peat – cheap and loaded with minerals, the most common types are peat moss and humus.
Sphagnum moss – lightweight with high water retention, more expensive than peat.
Coco coir – made from shredded coconut husk, very absorbent.
Rockwool – retains water while also aerating roots.
HEC (hardened expended clay) – no nutritional value, but drains and aerates well.
Vermiculite and Perlite – additives that hold moisture and nutrients.
Growstones – pellets of recycled glass made to be highly porous which both retains moisture and aerates roots.
How to grow cannabis
Whichever strain of cannabis you choose to grow, the instructions and grow time will be the same. The first thing to do is to make sure your grow area is at a constant temperature between 80 and 85 degrees Fahrenheit (about 26 to 30 degrees Celsius). You will also need to check the temperature of the water in your system, which should be between 63 and 72 degrees Fahrenheit (about 17 to 22 degrees Celsius). This will keep your plant’s roots healthy by maximising nutrient uptake and making sure there is enough dissolved oxygen in the water to prevent root rot.
Next, make sure you use filtered or purified water for your plants, as you don’t want to feed them fluoride and chlorine. Then add the nutrients to the water and check the pH level, ensuring that the solution is slightly acidic (between 5.5 and 6.5). Once you have done this, is it time to position your grow light according to its installation instructions, and use the grow light correctly for each growth stage. The seeds won’t need light to germinate, but as soon as the shoots appear you should switch on your grow light.
About 1-2 weeks into the flowering stage, you will have to separate the male plants from the female plants to prevent them from producing seeds. The male plants produce balls (yep!) and aren’t smokeable, so unless you want your plants to produce seeds you should get rid of them. The females produce small white hairs, so keep these plants as they are the ones that produce the bud!
Around two weeks before harvest time, you just want to feed your plants water to avoid the nutrients flavouring the buds. During harvesting, you need to trim the plants and store the buds in an airtight container to cure for two weeks to a month, and you’re ready to enjoy!
- pH levels are important for the roots to absorb nutrients properly – make sure you test the pH of the growing medium and nutrient solution regularly. It should be between 5.5 and 6.5, and can easily be rectified by using a pH control kit.
- Root rot can be fatal to your plants, especially if they are on an interconnected system. The roots will turn brown and begin to smell, and the leaves will turn yellow and wilt. Prevent this by keeping your reservoir away from light and heat, and don’t overfeed or overwater your plants. Keep your system clean and water well oxygenated. Adding beneficial bacteria to your nutrient solution can also help prevent root rot.
- Water your plants every few days when they are young, and once a day when they are flowering.
- Monitor your plants carefully through each growth stage, as their needs will change.
- Begin to harvest when ½ or ¾ of the white hairs on the female plants have turned a yellow-brown colour. The buds should snap off cleanly and not bend.
Types of Hydroponic Systems for Growing Marijuana
Here are the main types of hydroponic systems:
- Nutrient Film Technique (NFT)
- Aquaponics – fish are used in the water to provide the plants with food (we won’t discuss this method as it also involves fish care and gets a bit complicated)
- Deep Water Culture (DWC)
- Drip or Top Feed
- Ebb and Flow / Flood and Drain
Nutrient Film Technique (NFT)
This system uses a shallow film or layer of nutrient solution at the tips of the plants’ roots. A capillary mat is often laid down, as the porous mats help keep the solution evenly spread. The rest of the roots are exposed to air, so they are not at risk of being drowned or stagnating.
Whilst NFT systems are efficient and low maintenance, they are hard to set up because it is difficult to get the balance of solution-to-roots right. They also tend to work better for smaller plants.
Aeroponics with Misting (Fogponics)
This method applies a rainforest-like atmosphere to the roots, where the nutrient solution is misted and directed at the hanging roots of the plants. It involved lots of pipes and pumps, so if you are ready for the maintenance then this method will be good to you, as it is one of the most efficient and high-yielding options on the market.
- One of the fastest growing and highest yielding systems available
- Plant roots are constantly supplied with oxygen
- Most efficient use of water and nutrients
- Little chance of algae growth as no lights touches the roots
- Relatively disease-free environment
- Space efficient as plants can be grown close together without the risk of overcrowding
- A certain level of cannabis growing experience is needed as there is only a small margin for error
- High maintenance – more technical moving parts such as pumps that may need to be replaced
- Constantly needs electricity
- You need to be able to respond to problems within an hour, or else the roots will dry out
Deep Water Culture (Hydro Pots or Bubbleponics)
This is a good system for beginners, as it is cheap to buy and easy to set up and use. It contains a bucket/reservoir with the nutrient solution inside, a basket containing a peat or Rockwool growing medium for the roots to grow through, and finally a submerged air stone which oxygenates the nutrient solution.
Each of these units houses one marijuana plant, but it is possible to connect a few together with irrigation tubes into a single reservoir. For these joined buckets, nozzles are used instead of air stones to oxygenate the water. The water and nutrient solution has to be changed and the inside of the bucket has to be cleaned roughly once a week.
- Easy to assemble and maintain
- High yielding due to large root growth
- Good for beginners
- Spare pump required in case of failure
- Difficult to maintain correct water temperature
- Small DWC systems are liable to water evaporation, affecting the pH level of the nutrient solution
- Susceptible to contamination and stagnant water
Drip or Top Feed Hydroponics
A network of tubes constantly drips or sprays the nutrient solution onto the roots of the plants to ensure maximum nutrition.
- Relatively cheap
- Low maintenance
- No need to empty or replace the reservoir
- Not very environmentally friendly, as water and nutrient solution run off the roots without being absorbed and are wasted
- Tubes can clog
- Pumps may fail and will need to be replaced
- Timers used to control solution distribution may also need replacing
Ebb and Flow / Flood and Drain
This system periodically floods and drains the roots of the marijuana plants. This enables you to control the irrigation levels of your plants, and helps to avoid stagnation. The roots also get lots of oxygen as the solution drains away. You will need a timer to help you know when it is time to flood and when it is time to drain.
- Easy to use
- Highly productive
- Dry periods help prevent root rot
- Requires lots of maintenance in case of timer or pump failure
- High running costs from replacing water and solution often
- Different schedules are required for vegetative and flowering stages
It’s time to review some hydroponic systems, now that we know how they work!
PowerGrow Systems DWC Hydroponic Bucket Kit 5 Gallon 6 Inch
This deep water culture system takes up a lot of floor space but is great for larger cannabis plants. It comes with a basket lid, air pump, air stone, tubing, an FDA-approved 5-gallon bucket, and Rockwool for the growing medium. Note: be careful when handling dry Rockwool as it is irritating to the skin. There is also a water level marker and a bucket drain, making it easier to clean out the bucket and replace water levels.
Current Culture Under Current Solo 13 (8-inch Net Pot, 13 Gallon Grow Module) CCH2O UCSOLO13
This is a professional standard DWC system that uses sub-current culture technology to keep highly oxygenated water circulating the roots, keeping the pH and nutrient levels constant and the plants well fed. This system is low maintenance and easy to use, and produces large plants with high yields. The drain valve makes water changes easy, and the circulation system means that water changes are required less often, saving you time and money.
HTG Supply Bubble Brothers 6-Site DWC Hydroponic System
The Bubble Brothers’ hydroponic system is self-contained and easy to maintain, and comes with everything you need to get started (except nutrients, pH tester and balancers). The air pump and air stone are of commercial quality, and do a good job at oxygenating the water. The pots are a bit on the small side, but they take up less space. The system comes at a good price, and is great for beginners.
AutoPot 4 pot System Gravity Fed Watering System
This setup includes one 12-gallon reservoir and four smaller 3.9-gallon pots. It uses gravity to feed your plants, so none of your nutrient solution goes to waste. There is also no need for pumps or timers, cutting down your electricity costs and the need for replacements. This is great for beginners and those without lots of time and money to spend. The one potential issue with this system is that if the central reservoir becomes contaminated, all your plants will suffer.
Oxygen Pot Systems 6-Site XL Super-Flow (Digital)
The Oxygen Pot ebb and flow system has a digital control unit, allowing you to control fill and drain cycles accurately and efficiently. You can also set water levels, making this system flexible and customizable. The pots within the buckets are made of a breathable fabric which promotes air pruning. This happens when the roots grow through the fabric and dry out, causing more efficient roots to sprout laterally away from the dry roots, creating an efficient root system. This leads to faster plant growth and a higher bud yield.
Viagrow V4X4COMP Ebb and Flow Hydroponic System Tray
This system includes a tray made of high quality welded metal, a stand, tubing, timer, pump, and a potting medium. Each of the 25 pots hold one gallon, but these can be replaced with larger or smaller pots depending on how many plants you want to grow and how big they are. The downside to this system is that it is tall, thereby limiting the vertical grow space of your plants.
General Hydroponics Waterfarm Complete Grow System Kit
This kit is simple and inexpensive, making it great for beginners. The system can be expanded to accommodate more plants, and can be packed close together to take up less space. This is a drip/top feed system, which gives seedling an extra growth spurt in the first few weeks. It includes a 2-gallon reservoir, basket, tubing, pump, air stone, clay pellets and nutrients. One thing to be careful of is the pH level of the water, which young plants are especially susceptible to.
General Hydrpopnics EcoGrower Drip Hydroponic System
This kit includes everything you need to start growing your plants (except a pH balancing kit). It has a single reservoir, making refills easy. This system is relatively cheap and easy to maintain, again making it perfect for beginners. However, the pots could be a bit bigger.
SuperCloset Superponics-8 Hydroponic Plant Propagation Reservoir System
This system combines top feed and DWC systems to create an effective, failsafe hybrid. The system is small and quiet, and is relatively easy to clean and do water changes. It is quick to set up, and easy to use. If you have limited space or are legally limited to grow only a small number of plants, this is the system for you.
General Hydroponics RainForest 66 Aeroponic System
This aeroponic system comes with a 17-gallon reservoir, 6 plastic containers with CocoTek liners, a sprayer and a 3-Part Flora Kit. The all-in-one setup is quick and easy, but the pots are on the small side, and the water has to be changed once a week. The price point is good though, and maintenance is relatively easy.
We hope this comprehensive guide and set of reviews helps you in your cannabis growing ventures!