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Table of Contents

Hydroponic Cannabis Growers Guide

Growing hydroponic cannabis can be a great learning process for growers. Not only can you grow amazing cannabis plants using this growing method you can learn so much about the plants themselves. If you are new to growing hydroponic cannabis this guide will walk you though what hydroponics is, how to grow using this growing method. We will also teach you the many different types of hydroponic growing systems, how to set them up and grow the most healthy cannabis you can.

Hydroponic Cannabis

What is Hydroponic Cannabis Growing?

Growing hydroponic (we are referring to as hydro from this point) cannabis is using a system to pour water and nutrients over your cannabis roots. You can do this either by hand or using pumps. By using this hydro fertilizer nutrient solution you can grow beautiful very large cannabis plants. There are some advantages to using this method of growing over soil that you can read more about here. 

Using hydroponic is growing cannabis without using a soil based medium. Everything in the system is inert, meaning that it has no nutrient value on its own to grow the plants. All the nutrients need to be added to hydroponics in order for the plants to grow.

Getting Started With Hydroponic Cannabis Growing

In this section we will help you get up and running quickly with hydro. If you have never grown hydro or organic soil cannabis before we highly recommend starting with organic soil cannabis cultivation, however if you have grown other types of plants with this method such as tomatoes, you can get started right away with little issue.

Hydroponic Cannabis DWC

Choosing the Right Type of Hydroponic Cannabis Growing System

There are many different types of hydro systems that a cannabis grower can choose to use to grow cannabis. While they come in all types, shapes and sizes they all do essentially the same things, nutrient solution made up of water and salt nutrients are delivered to the root system, the root system uses the water and nutrients to grow your cannabis plants. We will review some of the main types of systems and how they could benefit the way you would like to grow cannabis.

Hydroponic Wicking System

This type of system is by far the easiest type of system to use for growing cannabis with hydro. On top of that it is also the cheapest to run over some of the others we will review. You don’t need any pumps, air or electrical for that matter. However if you are growing many plants, and they will be very large this system shouldn’t be used. 

This type of system works by planting your plants into a medium like vermiculite or perlite, or even a mix of both of these mediums. Once you have your plant in a container and in this medium you will need a nutrient reservoir preferable under the container your plant and medium are in. A wick is placed in the nutrient solution under the growing container. The wick will move water slowly up into the growing container and feed the plant.

Hydroponic Drip Systems

This is one of the easier systems to use for growing cannabis. You can grow any size of cannabis plant in this system, and also more then one plant per system. This system works by slowing dripping nutrient solution over the plants roots, the plant uses the solution to grow. There are two types systems used for this type of system, a circulating type system, meaning that the nutrients are reused over and over. 

The other type of system is a non-circulating system, or sometimes called drain to waste system. This type of system drips the nutrient solution over the plant’s roots the same way, however once it goes over the roots it goes as waste.

Hydroponic Water Culture (Deep Water Culture, DWC)

This type of growing system works by adding the plant root directly into the nutrient solution in the container. This also requires an air stone to add oxygen to the water and nutrient solution as the roots need it to survive. This type of system is one of the more popular for growing cannabis plants. Most growers use a mesh pot to grow the plants in and then have the roots of the plant hang down into the nutrient solution. An air stone is then added to the bucket for oxygen. 

The containers can either be all hooked together with hoses or they can all be their one environment and not connected to each other.

DWC Hydroponic Bucket

Hydroponic Flood and Drain, Ebb and Flow

This type of system works just like what it is called. The plants are spended in a medium to hold the roots. The nutrient solution is then pumped into the growing container and medium, once the roots have been covered, the solution then drains back out into the solution container or reservoir. This process will happen over and over, depending on how often the plant’s roots need to be watered. Sometimes this can happen a few times per hour to every few hours depending on how many plants are in the system at one time, and water usage.

Aeroponic Cannabis Systems

This system is different from the DWC system described above as instead of the plants roots sitting in the nutrient, water solution the plants roots are suspended in the air, or just hanging. Then a spray nozzles, sprays the nutrient solution over the roots, and it runs off the roots and out of the container that the plant is growing in. This is a great system as it uses less water than the other systems we have discussed so far. However there is a great risk that the spray nozzle could be clogged and if the plant’s roots dry out it can kill the plant or do serious damage. This system works with any size cannabis plants that you would like to grow. It is also a very widely used system for cloning cannabis plants. The clones are placed in the system so that the spray lands on the stems in the reservoir and promotes root growth on the clones. 

Hydroponic N.F.T (Nutrient Film Technique)

This is another system that is widely used for indoor cannabis cultivation. This system uses pumps to pump a thin layer of water over the plant’s roots. Normally the plants are in long channels that hold net pots. The roots hang out of the net pots and into the channel where the nutrient solution is pumped over them. The channel is on a very slight slope, so the solution runs down hill and naturally back into the reservoir and then is once again pumped back in this cycle that will repeat. This is a great system for growing cannabis and we have found that it works really well for growing massive plants.

What is the most efficient hydroponic system?

Well this is a very loaded question as we believe that there can’t be the most efficient system for growing hydroponic cannabis plants. When picking a system it is best to know each of the system’s features and then use these features to decide which system is right for you to grow with. If you are growing massive cannabis plants that will need good support, then a DWC system may be the most efficient system for you. If you want to grow hundreds of cannabis plants that are only 1 foot high then an N.F.T system would be very efficient for you. 

If you are just starting out and want to learn and grow one hydroponic cannabis plant then a wick system would be cheap to run and work well in this case without a major investment. 

If you are only a hobby cannabis growers then using a smaller system is recommended. If you are looking to grow many plants then you will need to look into a much larger system.

What is the best hydroponic system for beginners?

If you are a beginner hydroponic grower, but have other growing experience then some great systems to get started with are DWC, Wick System, and N.F.T systems. If you have no other cannabis growing experience we would recommend starting with DWC, or a Wick system. These two systems are very easy to use, if you are just getting started. When you first start out growing hydroponic cannabis, taking as many variables out of the equation, like pumps, and complicated nutrient mixes is highly recommended.

Does hydroponic cannabis grow faster?

This depends on many variables like growing light, grower experience, and cannabis growing environments. However side by side a hydroponic cannabis plant will grow faster than a soil grown cannabis plant. This is because hydroponic cannabis has access to everything it needs to grow without having to go out in the soil looking for it. Keeping in mind that the growers hydroponic cannabis system must be dialed in, with everything in check. If something goes wrong in a hydroponic system it can really slow growth as compared to if you have a problem in soil grown cannabis. Experienced growers can shave a week to as much as two weeks off the flowering time of the plant in a hydro system.

What size air pump do I need for hydroponics?

The bigger the air pump in your system the better. We recommend buying the largest air pump you can afford for your system. Pumping oxygen into the nutrient solution is very important in hydroponic cannabis systems. If the pump breaks down the plant’s roots can drown quickly without a working air pump. You can buy ones that have many outlets and can be used with up to 8 air stones for water into the system.

Air pump for Hydroponic Cannabis

Types of Hydroponic Cannabis Growing Mediums

So now that we have reviewed the types of systems that can be used to grow cannabis with hydroponics, it’s time to review the types of mediums that you can use in those systems. It is important to remember that any medium you use should be inert. This means that it will have a neutral PH value (except for rockwool more on that later), be clean, have no nutrient value and have good water and air retention. The medium should also fit and work well with your system. 

There are three different things that are important when you pick what medium you will use. WHC, AFP, and CEC.

What does WHC Stand for?

Water Holding Capacity, this term is used for how much water the medium can hold while still holding a good supply of oxygen. This is important because some systems work better depending on the WHC of the medium used. Wick hydroponic systems work great with higher WHC mediums like Coco.

What does AFP Stand for?

Air Filled Porosity, this term is used to describe the air flow in the hydroponic medium that you are going to use. The less AFP in your medium the more at risk your plants will be of having root rot, or the plants drowning in the medium without enough oxygen. When picking your medium be sure that it has a good AFP.

What does CEC Stand for?

Cation Exchange Capacity, this term is used to describe what and how many native minerals are in the hydroponic cannabis medium. The more minerals that you have in the medium the more it will interfere with your nutrient solutions. This is why growers like to use inert mediums that contain little to no minerals and nutrients. Having a low CEC will help hydroponic cannabis growers monitor their system much easier then with higher CEC mediums. A good example of this is Coco Coir, it has a higher CEC as it breaks down, this is why you will see special nutrients online just for growing with this type of medium. 

Main Types of Hydroponic Cannabis Mediums

These are the main types of mediums you can use, however there are many others you can look into.

Rockwool Medium

Also called Stonewool, this is a hydroponic material made of spum basalt rock fibers. It has excellent WHC, very low CEC which means that it will drain and hold oxygen very well. Rockwool will require the growers to presoak it in a lower PH solution of water to bring down the medium’s high PH values, we suggest soaking it in a 5.5 solution 24 hours prior to use. This medium comes loose, in blocks, and smaller rooting cubes.

Rockwool

What is Rockwool?

Also called Stonewool, this is a hydroponic material made of spum basalt rock fibers. It has excellent WHC, very low CEC which means that it will drain and hold oxygen very well. Rockwool will require the growers to presoak it in a lower PH solution of water to bring down the medium’s high PH values, we suggest soaking it in a 5.5 solution 24 hours prior to use. This medium comes loose, in blocks, and smaller rooting cubes.

Coco Coir (Coconut Fiber)

Another very widely used hydro medium, this works well in wicking systems and hand watered systems, using pots and containers. It also is a great medium to use in Drip Systems.

Coco Coir

What is Coco Coir?

This medium is made up of the shredded husks of coconuts. This is a waste by product of the coconut industry and is an excellent biodegradable organic growing medium for hydroponic cannabis. It has a high WHC, and average CEC and AFP that is not quite as good as rockwool in this respect. Because Coco Coir breaks down quickly, and adds nutrients as it breaks down over the growing cycle, growers will need to use special hydroponic nutrients that will account for this. The nutrients will specify if they are made to work with Coco Coir growing mediums.

Expanded Clay Aggregate

Another great hydroponic growing medium, growers can get these by the bag. Grower can use these in DWC, and also Flood and Drain systems work very well with these. The only downfall for these are that they can be in very heavy bags for growers to use, and carry. 

Clay Pellets

What is Expanded Clay Aggregate?

This medium is round pieces of heat-expanded clay that is blown up into round clay balls that can be used in growing systems. This medium can drain very fast and has a very low WHC, but has awesome AFP for the cannabis rooting system to grow in. It will drain very fast so we recommend it in systems that will not dry out quickly like DWC. In these types of systems it is used to hold the roots in place while the main root system sits in the water with air being pumped in.

How Many Different Types of Medium are There?

There are many more types of mediums for growing hydroponic cannabis, these are some of the ones that we have used over the years for growing cannabis plants. Trying different mediums can help you pick the ones that will work well in your system. If you find that you are having troubles with a type in one grow, in the next swap out that medium with another and see how it works, you may have better luck.

Setting Up a DWC Hydroponic System

This system is a good system to grow cannabis. We will walk you through setting one up for hydroponic cannabis. This system doesn’t take much time to set up and you can also use your existing lights, and your tent depending on how many plants you would like to grow using this method.

What will you need to Set Up this System?

  • Four Buckets and Lids (Black) + if you intent to add more
  • Four Five inch Net Pots +
  • Five Inch Hole Cutter Saw
  • Half Inch Drill Bit
  • Air Pump with Four Outlets
  • Air Tubing
  • Clean Water Source 
  • Hydroponic Cannabis Nutrients
  • Loose RockWool or Clay Pellets

How to Put this DWC System Together?

First get your five inch hole cutter saw set up and ready to drip five inch holes in the lids of your buckets in the dead center. This is where your net pots will sit, so make sure that there is enough of an edge around the holes to keep the net pots from falling through. Once the plants get bigger and heavier they can push the entire plant down though the holes into the growing nutrient solution buckets. Plants can grow massively in these types of systems. For this reason cut the holes smaller than the rims of the net pots. 

Next take your half inch drill bit and also drill a small hole in each of the lid next to the four inch net pot holes. This will be used to feed your air pump hose though. 

Inside DWC Hydroponic Cannabis System

Putting the DWC all Together

So that is it for building these easy to do systems! Not too bad eh? Now it is time to put them together and get the hydro system up and running. 

Place the air tubing in through the smaller half inch holes and make sure it is long enough to reach the bottom of your buckets, and the air pump that you will be using wherever it will be placed when the system is running. 

Next add the airstone to the end that will be placed into the buckets. One in each bucket for each air outlet. Then connect each to the air pump. Place the bucket covers over each of the buckets and place in your net pots. Mix your nutrient solution with water in each of the buckets and fill them about ½ to ¾ full. 

Then add your net pots to each drilled hole and fill them with your chosen medium above. Start your air pump and add your cannabis plants to the center of each net pot in the medium. 

Your system is now up and running! As your roots are not down far enough yet into the growing nutrient solution you will have to hand water for the first week. Just lift the edge of the cover up and take some of the solution and pour it over the tops of the medium a few times a day, more if you used Expanded Clay as it will dry out faster. This will only need to be completed the first week as the roots will grow quickly to the solution below. 

Hydroponic Cannabis Nutrients

What is Hydroponic PH in your System?

When using this method to grow cannabis the PH in your system must be monitored on a daily basis, if the PH becomes out of range it can prevent the plant from taking in the nutrients that it will require to grow. When this happens the plants will start to show signs of nutrient deficiencies. If the solution gets far out of the correct range it can even cause an issue called “nutrient lockout” that will prevent the plant from using nutrients even after the PH issue has been corrected. We have a great article you can read here about PH in cannabis cultivation. 

The PH of your hydroponic cannabis growing solution should be in the range of 5.5 to 6.1.

What are PPMs in Your Hydroponic System?

PPM stands for the Parts Per Million of your nutrients in your hydroponic solution or even the PPM of your water that you would like to use for your solution. In more detailed terms it is the concentration of soluble minerals in the growing solution for your hydroponic plants. Growers also refer to this as EC or Electrical Conductivity of the growing solution. Like PH it is measured on a scale with the lower amount of minerals showing less on the scale, and more minerals should be higher on the scale. Unlike PH above this can change depending on the growing cycle of the plants. As your plant grows into flowering it will require higher PPM in the solution to keep growing efficiently.

Most nutrients that you will purchase will give you a growing chart with the recommended PPMs of the solution as you grow your plants. Following these guides will help you mix your nutrients correctly for each growing cycle. .

Mixing at a low PPM can cause nutrient deficiencies as well, and mixing solution with a very high PPM can burn your plants. It is important to mix your solution following the guideline of the product. 

Buying Good Meters for PH and PPMs

To check your solution we recommend purchasing a meter. You can buy both a PH and PPM meter that you can place the end in the solution and it will tell you within a minute or two if the solution is in the range for the plants to grow best.

PH and PPM Meters

Looking after your DWC Hydroponic Cannabis System

Now that your system is up and running, it will require your attention to keep it running efficiently. You will need to check water levels, and PH levels and PPMs of the solution each day to make sure that there are no issues that will affect the growth of your hydroponic cannabis plants. 

This may require you to add more plan water if the PPMs get high, or adding PH up or down depending on the PH range of your solutions. If any of these things get out of range you can do things like PH up or PH down to the nutrient solution to lower the PH or increase the PH of your solution. If your PPMs get too high, they can be fixed by adding more plain water, this happens when plants use water and not the minerals in the solution. Likewise the solution can lower in PPMs if the plant uses more minerals than water in the hydro solution. 

How fast do Plants Grow in Hydroponics?

If your hydroponic cannabis system is running effectively, your plants will grow very fast, you will notice an increase in growth over a soil growing setup.

How long should I run my Hydroponic System?

This is fully dependent on the type of system that you will be running. Some systems need to be running all the time such as an NFT hydroponic cannabis system. Others only certain parts of the system need to run all the time such as the air pumps in a DWC growing system. A system like Flow and Drain will only need to run with the water pump every four to five hours. 

Pro and Cons of Running a Hydroponic Cannabis Growing System over Soil

As with any system there are pros and cons of using these types of systems over soil growing cannabis. We have a more detailed article you can read here about growing hydroponic cannabis vs soil cannabis.

Cons of Running a Hydroponic Cannabis System

  • It is much harder to run a hydroponic growing system over soil especially for a new cannabis grower. 
  • The hydro grower will require more tools for measuring things like PPMs and PH as discussed above. These tools can cost hundreds of dollars depending on quality and brand. 
  • Hydroponic systems can cost much more for material than soil grown crops. Also nutrients can also add up quickly over a growing cycle. 
  • Breakdowns in equipment like water pumps can kill your crop overnight. 
  • Finding equipment can be much more difficult if you don’t have a local hydroponic store in your area

Pros of Running a Hydroponic Cannabis System

  • Plants can grow much faster in a hydroponic system, and also have a much larger yield. 
  • Hydroponic systems are much easier to run once you get good at growing with this method.
  • Hydroponic cannabis systems generally have less pest than in soil systems.
  • Not having to haul heavy soils in and out of your growing spaces.

Final Thoughts

We hope that tips and information in this hydroponic cannabis growers guide can help you understand and get started growing hydroponic cannabis plants if you wish. Growing using the methods in this article can be very rewarding and while taking some skill to learn, can be easier then with growing soil cannabis plants. 

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