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Hydroponics - The Guide

So you’ve decided you want to grow some fine cannabis but you might be a little confused with all the details of choosing and setting up a hydroponics system? Or perhaps you’re a seasoned grower but need a refresher or a quick reference? Here we cover the basics of what hydroponic systems are, how they are used for cultivating marijuana and the different kinds available.

Hydro under lights

The Basics

So what are hydroponics all about? It’s common knowledge that plants naturally grow in some type of soil or solid grow medium in order for roots to establish, which will then provide nutrients from the ground to feed the plant and allow it to flourish. Hydroponic gardening simply removes the soil and replaces it with an inert, soilless medium such as rockwool, clay pebbles or coco coir. Once established, the roots are then fed with a nutrient solution, the possibilities of which are numerous, more on that later.

So what is the purpose of ditching traditional soil and replacing it with a hydro kit? Traditional soil does have certain advantages over hydroponics but the main reason why so many growers go hydro is simple: bigger yields in a shorter amount of time. Traditional growing methods are dependent on the environment they are grown in, so they are susceptible to the sun (or lack thereof), precipitation (or lack thereof) and potential pests. With a hydroponic system, the grower is in complete control of all three elements. With ideal conditions (the right amount of light and nutrients), plants grow at an explosive rate (30-50% faster) and are ready for harvest much sooner than when grown in soil.



The History of Hydroponics


Hydroponic gardens can be dated back to the Hanging Gardens of Babylon as well as the Floating Gardens of China. This method has evidently been around for quite some time, however the credit for modern hydroponics goes to a man named William Frederick Gericke.


In 1929, while working for the University of California at Berkeley, he publicly promoted the notion of using solution culture for producing agricultural crops. The general public, along with Gericke’s colleagues doubted the idea, so to prove them wrong he grew 25-foot tomato vines using nothing but water and nutrients. He initially wanted to call the method aquaculture but later realized the term already existed and referred to the culture of aquatic organisms, so he went with the Greek terms of ‘hydro’ (water) and ‘ponos’ (labor) to get hydroponics. The method didn’t take off until after World War II when it expanded to countries in Europe, the Middle East and the Soviet Union


The prohibition of cannabis in the United States also made the conditions ripe for applying it to growing marijuana domestically vs. having it imported from countries like Mexico. Growing moved indoors out of sight of pesky law enforcement and could be done at a much faster rate with massive yields while using relatively little water and nutrients.



Types of Hydroponic System


Hydroponic kits can seem confusing and intimidating to set up, but despite all the necessary components, it is possible to run an automated system with relative ease. Let’s look at some of the most popular methods employed by growers today.


Aeroponics Setup
  • Aeroponics – The name certainly sounds fancy and high-tech and there might be some additional equipment to procure but this system simply involves getting oxygen to the roots by spraying a mist of aerated, fast-moving nutrient solution on them. Plants (including clones) can be held in little baskets containing rockwool or clay pellets. The roots grow out of this basket and then are showered with a very fine mist.
Deep Water Culture Hydroponics
  • Deep Water Culture (DWC) – DWC involves a combination of oxygenated water and nutrient solution over which plants are suspended. The roots grow out into deep buckets, which contain oxygen stones at the bottom.  With complete access to water, nutrients and oxygen, plants grow extremely fast and yields are enormous. The DWC system also allows for many variations to the setup, making it quite the versatile technique.
Bubbleponics system
  • Bubbleponics – Perhaps the most fun-sounding name of hydroponic techniques, bubbleponics is nothing more than a Deep Water Culture system that is top-fed. Here plant roots receive a stream of aerated nutrient solution from above, which makes roots grow even faster in the vegetative period.
Drip System Hydroponics
  • Drip System – Drip irrigation provides water to the planting medium by way of a drip emitter connected to tubing. The emitter is placed in a container or close to the root ball of every plant in the system. A flexible tube carries water from the nutrient reservoir and runs the length of the entire garden. This main line has little spaghetti tubing connecting it with the rockwool cube or plant container with an emitter that sits on a spike. The water can be recycled, though occasionally it gets discarded.
ebb and flow hydroponics
  • Ebb & Flow –This is the method that most people probably think of when they hear the term hydroponics. Also referred to as Flood & Drain, rockwool cubes are utilized here as the soilless medium (though any inert soilless medium will do) which is then kept in a tray. From a separate container, nutrient-rich water periodically gets pumped into the tray, resembling a natural rain cycle. Once the plant roots have been bathed in the nutrient solution, it is then drained or pumped back into the original container to be used again later.
NFT Hydro System
  • Nutrient Film Technique (NFT) – In this setup, a shallow film of water is continuously moved by gravity over roots that grow in a tray or PVC tubing that is aerated using water circulation, bubblers or sprays. The solution usually gets recirculated back into the reservoir. This method is better suited for small plants as the roots of large plants can end up blocking the water channel.
Wick System Hydroponics
  • Wick system – Probably the easiest hydroponic system in design, setup and maintenance. Doing most of the work here is a wick that uses capillary action to draw water towards the roots. The plant is kept above a reservoir, a rope connects the two at each end, pulling water from the reservoir into the plant container. Much like water being pulled up by a paper towel, no additional work needs to be done by the grower to keep the medium moist, making it an easy passive hydroponic system.


Lighting System and everything you need to know for growing under lights


Hydroponic Grow Mediums


Once you have decided on a specific hydroponic kit or setup, now it’s time to choose a suitable cannabis growing medium. Depending on the type of design, some mediums are more suitable than others though the types below should cover any basic setup.



Clay pebbles for hydro systems
  • Clay pebbles – Also known asLight Expanded Clay Aggregate (LECA), this is perhaps one of the most versatile mediums in terms of applicability. It can be successfully used in all of the hydroponic systems mentioned in the previous section. Natural clay is baked at a high temperature for several hours, which makes pellets expand into a semi-porous medium that is very good at aerating roots. LECA also uses capillary action to draw in moisture and thanks to the space between the pebbles, root rot from overwatering is one thing you do not need to be concerned about. Best used in hydroponic baskets.


Coco Coir
  • Coco coir – Coco coir has become a very popular medium for hydroponic growing as it very closely resembles soil, is highly productive yet affordable and can hold a lot of air. It is obtained by grinding up or shredding coconut husks. This fiber provides plenty of aeration and water retention. It is a biodegradable medium that is also rot-resistant. Growers like to use it all by itself or with a 50/50 mix of LECA or perlite.


Perlite for Hydro Systems
  • Perlite – Many people recognize perlite by its popcorn-like appearance but perlite is actually sand or volcanic rock that has been expanded using heat. A very common soil amendment, it mixes well with other mediums as it increases drainage and prevents salt build-up from fertilizers. Because it also doesn’t retain water, roots get more oxygen which translates to faster growth. Depending on the choice of other grow mediums if you are mixing, aim to add 10-20% if not using a lot of supplemental nutrients, 30-50% if you are using a nutrient-heavy solution for big yields.


Rockwool for Hydroponics
  • Rockwool – Also an incredibly popular medium, rockwool is made from melted basalt and chalk and then spun it into its wool-like form, after which it gets processed into various shapes, such as cubes or trays. It is excellent at retaining both water and oxygen so plant roots will be incredibly happy. It is also very-well suited for rooting clones as it provides a stable medium.


Setting Up


Putting together a complete kit may seem like a lot of work, and the equipment list can seem long, but once you have everything together and closely follow setup instructions, it’s not as complicated as you might think. If you are a novice or have an aversion to DIY projects, ready-made grow kits are available for purchase either online or at hydroponics stores where you can obtain further information and/or advice. If you’re up for a challenge and aren’t afraid to tinker with tools, then read on! Note: This is just a very basic guide that will cover the rudiments needed for operating a simple hydroponic system. Depending on the final design, certain parts may be additionally required.

  • Lighting – Unless you’re growing in a greenhouse, you will need some sort of artificial lighting. The most common types are High Intensity Discharge (HID) lamps, either high-pressure sodium or metal halide, though LED fixtures have become enormously popular as they require much less energy to run and are incredibly efficient at providing the right light spectrum to plants. They also emit less heat, making it cheaper to maintain the right temperature in your grow space. Some hangers will come in handy as well and remember to use a timer to regulate the light cycle in your garden.
  • Planting containers/plant medium – Depending on your chosen hydroponic method, you will require either trays, troughs, buckets, and/or baskets to house your preferred medium. If running a simple Ebb & Flow kit, a tray, a nutrient reservoir and some rockwool should do the trick. Remember to include accessories such as tubes, valves, pumps and air stones.
  • Ventilation and odor control – Since you are taking over for mother nature, you will have to provide adequate air and ventilation for your garden. A proper oscillating fan will be necessary to circulate air throughout. Unless you devise a closed-loop system, you must also factor in air intake and exhaust. For this purpose, a carbon filter with a fan and perhaps silencer will be necessary to minimize any odors emanating from the garden. Ducting tubes will also come in very handy here.
  • Meters, other accessories – In order to maintain a healthy garden and prevent diseases and pests, optimal ambient conditions for your cannabis plants are a must. For this you will need a digital thermometer to control temperature, a hygrometer to monitor humidity and a pH meter (preferably digital) to monitor the pH of your nutrient solution. An EC (electrical conductivity) meter will allow you to check the amount of nutrient, salts or impurities in the nutrient solution. If any of these are not within a healthy range, your crop is bound to suffer. Nutrient solutions and pH amendments are also crucial to maintain a healthy garden..
  • Seeds/clones – Once you have all the equipment and have set everything up, it’s time to bring in some plants.You will need some seeds, though clones are a good option and will be ready faster as they don’t have to germinate, which can take several days. Selecting the right kind of strain is also key. If you’re growing for fast, big yields anything short and bushy will be very well suited for an indoor hydroponic garden. Despite the fast growth rate, landrace sativas might be difficult to manage as they tend to stretch out, requiring lots of bending and/or pruning so autoflowering varieties, traditional indicas or hybrids are the wise choice.

A Few Things to Remember


The nice thing about hydroponic systems is that once you have done the dirty work and set everything up, the system will do most of the work for you. Maintenance is generally easier in a hydroponic garden, but there is some due diligence to be done if you want your crop to be a success.


  • Regularly check the pH of your nutrient solution so that it is in the ideal range. Cannabis plants perform best in hydroponic setups when the nutrient solution is within the pH range of 5.5 - 6.5 with 5.8 being the sweet spot. pH up&down control kits are easily found online or at your local hydroponics shop.


  • Your cannabis plants will also have to be checked for the right amount of nutrients, which you can measure with your EC meter. The macronutrients to pay attention to the most are nitrogen (N), phosphorus (P) and potassium (K). Plants will require different ratios of these nutrients throughout the life cycle so make sure to adjust accordingly.


  • Temperature and humidity also affect the growth rate of your plants as well as things like susceptibility to mold or disease. Make sure the water temperature remains around 68°F (20°C) so that roots can absorb nutrients. Cannabis plants prefer ambient temperatures of 70-85°F (20-30°C) during the vegetative stage and 65-80°F (18-26°C) during the flowering stage. The ideal relative humidity range for a cannabis environment is 40-55% so make sure you also have a proper hygrometer.


  • Lastly, cleanliness is next to godliness and you want to treat your cannabis plants like the goddesses they are, so keep your garden neat, tidy and clean! Every two weeks or so, it is a good idea to scrub trays, buckets, tubes and reservoirs which will protect your plant roots from potential pathogens and diseases.




Pro-Tip: If you play your cards right, your yield will be quite big, however this means that buds will be so heavy they can barely support themselves and might fall over. If the plant is diverting its energy into supporting its own weight, that means less energy is going towards flowers. To help support your plant as it grows, use a light stick, tomato cone or netting.

Even Proer-Tip: You can also tie a yo-yo to your plants and hang it from the ceiling or the top of your garden. As the flowers get bigger, the yo-yo string pulls it up towards the light, becoming shorter in the process and helping your plant reach that precious light.


Editors Summary

Think you still want to give hydroponic growing a shot? You understand the basics of how growing plants in water works, all you need now is to choose the most suitable method from the descriptions above, pick a medium for housing your plants, gather the necessary tools and equipment and off you go. Doing a bit of homework also never hurts in the long run so having access to information and grow advice is key to avoiding mistakes and fixing errors.