Hydroponic Growing Systems
There are a variety of hydroponic systems that are well-suited for growing marijuana indoors. Each has its own advantages, and they come with varying degrees of complexity. The choice depends largely on personal preference and your growing goals.
Most hydroponic shops will offer complete kits with good advice. If your budget stretches to this then they are ideal, especially when you’re starting out. However you will end up buying equipment that you don’t really need.
Your other option is to DIY to some extent. It is relatively easy to construct your own systems following the basic principles.
This page will discuss the seven most popular hydroponic systems for growing marijuana, plus two Dutch techniques that can be used in conjunction with these systems to improve yields.
Aeroponics – The art of growing marijuana with the roots dangling inside a light and water tight box and small emitters producing a fine mist on a regular basis.
Deep water Culture (DWC) / Recirculating Direct Water Culture (RDWC) / Bubbleponics hydroponic system – In this system the roots are immersed in nutrient solution. An aeration stone is used to oxygenate the solution.
Continuous Flow / Top Feed System – These terms describe a variety of techniques which produce a ‘continuous feed’ of nutrients into the top of the grow medium. Examples of continuous flow systems include:
Nutrient Film Technique (NFT) – Your plants are held in aggregate above a slightly tilted tray, with a thin film of nutrients flowing from top to bottom past the roots of your marijuana.
Drip irrigation hydroponics – Small emitters drip feed your marijuana plants from the top, near the main stem.
Ebb and Flow hydroponics – A basic but functional system with your pots situated in a tray above the reservoir. The reservoir pumps the nutrient solution up and into the pan which ‘flows’ past the pots and in turn feeds them. The nutrients solution is then allowed to ‘ebb’ away back into the reservoir.
Wick System – A really basic system that is great for a couple of plants or if you are just starting out as there is no need for pumps, timers or aeration systems. Simply connect your pots with thick ‘wick’ dipped into the reservoir and capillary action will do the rest!
Sea of Green – A Dutch growing method which produces a Sea of Green heads (kolas), we love it.
Screen of Green – This is a Dutch growing method similar to Sea of Green, but using a screen to spread the leaves of each plant to maximize the amount of light they receive.
Things to Think About for Any Hydroponic System
There a few considerations that apply to any hydroponic set-up.
This is the vessel that holds the water and nutrients which are usually pumped through to your plants. When picking a reservoir keep in mind:
- Nutrient solution reservoirs should be as large as possible.
- Ideally a reservoir should be able to supply at least one if not two weeks of nutrients.
- Does it have a lid?
- Without a lid you’ll lose a lot water to evaporation.
- Where will you locate the reservoir?
- Keep it close to a water source
- Get one (or two) extras.
- Extra Reservoir #1 is good hold standing tap water for 2-3 days to allow any chlorine to dissipate and neutralize the pH.
- Extra Reservoir #2 is a back-up in case one breaks or springs a leak.
- Make sure it’s sturdy.
You should insulate your reservoir to help control the temperature of the solution. Elevating it one a brick to allow air flow all the way around helps, and some growers insulate with Styrofoam, foam rubber or even newspaper.
Essential pieces of hydroponic kit
Here are a few things you will need for any hydroponic set-up. If you don’t purchase a kit, make sure you collect them all separately.
- Hydroponic nutrientsfor vegetative and marijuana flowering stages
- pH Meter
- EC Meter
- An EC meter will tell you the concentration of your nutrient solution and most commercially available solutions will require you to check this
In an aeroponics system the plants roots hang freely in the air, with no growing medium necessary. Nutrient solution is sprayed on the roots continuously. The high levels of oxygen available at the roots promotes the growth of microbes that digest the nutrients and make them easily available to the plants.
Pros of growing marijuana with aeroponics:
- Saves on Water
- High Oxygen=Efficient Use of Nutrients
- High Yields
- No Medium Necessary
Cons of an aeroponics hydro system:
- Expensive to Start
- Noisy (not horrible, but not the stealthiest system)
- Vulnerable to Power Outages
The Latest Development in Aeroponics for Growing Marijuana:
The Tower Garden is the latest in hydroponic technology. This vertical grow set-up uses aeroponics to feed plants, while recycling 100% of the water it uses. It works great for either an indoor or outdoor grow.
Here’s another way growers are using Aeroponics for space-saving vertical grows:
Deep Water Culture (DWC) is a hydroponics system that suspends the plants’ roots directly into a nutrient solution that is highly oxygenated. They are effective and easy to build, making them a great choice for growers who are new to the world of hydroponic marijuana.
With DWC each plant has its own reservoir or bucket full of the nutrient solution. There is a container in the top that has a non-soil growing medium. The roots hang down into the solution below.
Pros of growing marijuana with DWC:
- Easy to DIY
- Inexpensive to Set-Up
- Fast Growth
- Large Yields
- Few Pest Problems
Cons of a DWC hydro system:
- Potential for Leaks, System Failures
- Cleaning After Each Grow
- Replacing/Cleaning Growing Medium
Continuous Flow refers to any system that provides a constant supply of nutrient solution to the roots in a stream or flow.
Plant roots need oxygen to survive and absorb the maximum amount of nutrients for the best growth. NFT provides air to the roots by leaving the majority of the root mass exposed to the air at all times.
The plants are grown in long channels with net pots to hold them in place. The bare root mass is protected from light by a collar, and a film of nutrient solution is constantly run through the bottom of the chamber. The plants get all the water and nutrients they need, without ever being starved for oxygen.
This system is very popular with large commercial grows. For the smaller cultivator NFT can be a bit complicated.
Pros of growing marijuana with NFT:
- Fast Growth
- Bigger Yields (up to 3X yield from a soil grow)
- Saves Water
- Accurate Feeding (No nutrient burn)
- Fewer Pests due to Lack of Soil or Growing Medium
Cons of a NFT hydro system:
- Finely Balanced System Requires Careful Maintenance
- Power Outage Could Destroy Crop
- Requires Careful Balance of Air, Nutrients and Water
- This system is less forgiving than other hydroponic set-ups, so we recommend it only if you are an advanced grower.
In a drip irrigation system a regulated flow of nutrient solution is fed to the plants from the top down. It can actually be used with soil as well as with hydroponic mediums. These are highly efficient and simple systems.
Pros of growing marijuana with Drip Irrigation:
- Water Efficient
- Less Chemical Nutrient Residue in the Environment
- No Wasted Nutrients
- Grow More Plants in Less Space
Cons of a Drip Irrigation hydro system:
- Blockages in Drip Emitters
- Time-Consuming Set-Up
- Use a Lot of Media
NEWS: Growing Water Intensive Marijuana Raises Environmental Concerns
Not worried about how much water your grow room consumes? You should be!
Growing marijuana indoors with hydroponics takes a lot of water. As the industry grows, many people are becoming concerned about the environmental impacts. The issue is especially hot in California, where the drought drags on. Using water efficient systems like drip irrigation can help resolve water issues.
Learn more about marijuana and the environment:
The Ebb and Flow system is a low maintenance system ideal for the amateur grower.
Plants are placed in net pots, usually filled with Rockwool or a similar hydroponic growing medium. The pots are set in a tray that holds about 6” of nutrient solution.
A timed pump periodically floods the base of the tray from a reservoir. When the pump switches off, the solution drains back down the same tube with the remainder staying behind in the medium which the plants then utilize.
To avoid flooding, an overflow pipe is fitted in the tray at the required level (just lower than the base of the plant stem) which feeds solution back into the reservoir. Remember to always keep your growing area higher than the reservoir. This way, when pumps are off or they are accidentally left on the solution will still drain back down into the reservoir and you should eliminate the chance of flooding.
Timings for watering vary according to the size and strain of your plants. A good starting point would be to flood the growing tray for 15 minutes, 3 to 4 times during the plant’s daylight cycle.
Pros of growing marijuana with Ebb and Flow:
- You Can Reuse Nutrient Solution
- Easy to Build
- Easy to Maintain
- Inexpensive to Build
- Can Use Any Medium
Cons of an Ebb and Flow hydro system:
- Height Restriction on Plants Due to Size of Reservoir and Tray
- Salts and Minerals Can Build Up on Growing Medium
- Need Additional Source of Nutrients for Small Plants
- The flood height might not reach the roots of small/young plants. You may have to supplement with drip irrigation at first.
A wick system works passively. There are no pumps needed to move the water but usually one is needed to keep the solution aerated. The nutrient solution is pulled up to the plant via a wick (you can use thick acrylic cord) by the force of capillary action.
The plant will take only the amount of liquid that it needs. Simply have the top end of the wick buried in the plant’s growing medium and the bottom end hanging in a reservoir of your nutrient solution. Wick grow systems are ideal for beginners as there is no way to overwater the plants and no chance of leaks or floods as the main reservoir sits below the plants.
Pros of growing marijuana with Wick Systems:
- Impossible to Overwater
- No Wasted Nutrients
- Simple to Build
Cons of a Wick hydro system:
- Requires Grow Medium
- Can Result in Build Up of Salts
- Large Plants Need More Wicks to Get Enough Water
Dutch Systems for Bigger Marijuana Yields
After all, who knows cannabis and cultivation better than the Dutch? These are two commonly used techniques to boost yield and save on space.
Sea of Green (SOG) is all about saving space while boosting yields. Here’s the basic premise: you switch your plants to flowering after only two weeks of vegetative growth. This means you can harvest much sooner than if the plants grew to their full size.
The yield per plant will be lower, but the yield per square meter will be higher than normal. SOG is a great technique to use when you have access to a large number of clones.
You don’t need any special tools or skills to do a SOG grow. The tight canopy of buds that form (the sea of green) form a uniform surface for light to hit, making this an especially efficient growing technique.
Pros of growing marijuana with SOG:
- More Harvests Each Year
- Higher Yields at Each Harvest
- Saves Space
- Uses Light Efficiently
Cons of growing marijuana with SOG:
- Requires a Lot of Plants
Screen of Green (SCOG) is one of the most productive marijuana growing systems around. It is essentially a training technique aimed at distributing the light evenly across all budding surfaces of each plant.
Young plants are trained to grow horizontally through a screen placed above them. This encourages bud development on side branch stems that usually are not productive.
The vertical growth of each plant is limited, and its energy is distributed laterally across the screen. It is the best way to get the most out of your lights or to maximize yields from a small or under lit grow.
SCOG require more effort than SOG, but your hard work will be rewarded with massive yields. Learn all about this technique and which strains are best suited for SCOG growing in our Screen of Green Grow Guide.
Pros of growing marijuana with SCOG:
- High Yields
- Most Effective Use of Small Space
- Most Efficient Use of Grow Light Energy
Cons of growing marijuana with SCOG:
- Timing is Essential
- This technique is easiest if you know your strain very well, and can predict just when flowering will start.
- Plants Get Stressed
- You are encouraging unnatural growth patterns which can stress the plant and cause hermaphrodites to develop
- You Must Trim
- Some trimming and pruning is required to keep buds exposed to the light and prevent crowding.
Latest Development in SCOG: Wacky Vertical Grows
Cannabis cultivators have started taking SCOG growing to a new level. Instead of a simple horizontal screen, they are using screens to grow plants vertically and even in circles! Check out these wild images of SCOG grows.
The Best Hydroponics System for You
Only you can decide which hydro set-up is the best for your grow. It depends on a lot of factors: how much money do you want to spend? Are you handy? What strain will you grow? How much work do you want to put in on a daily basis?
Growing marijuana indoors using a hydroponic system is very rewarding. Once you’ve chosen your hydroponic system, learn more about hydroponic growing with our Hydroponic Grow Guide.