How to

18 March 2021

A Guide to Hydroponic Growing

If you’re a cannabis grower or would-be cannabis grower, you will probably have heard of hydroponics. Hydroponic gardening simply refers to the process of growing plants without soil.

While this may seem counterintuitive, the flexibility, effectiveness and DIY-nature of hydroponic growing make the method a staple in the cannabis cultivation community, particularly favoured amongst those growing an indoor garden for its ability to provide year-round harvests.

What is Hydroponics?

Hydroponic growing is quite simply the growth of plants without soil. Typically, plants receive nutrients from the soil in which they grow. Hydroponics takes the soil out of the equation and instead uses a solution of nutrient-rich water to provide plants with proper nutrition.

Because the grower has control over nearly every factor of a hydroponic garden, it makes it the perfect choice for cannabis growers who are limited by lack of space or land. Instead of a giant hole full of soil, or a massive pot of potting mix, hydroponic gardeners suspend their plants’ roots in a soilless or inert medium, or sometimes right in the nutrient solution itself. This simple concept can be expanded to fit as large or small of a growing space as necessary, making it a perfect choice for indoor and home growers.

Advantages of Hydroponics

There are many advantages to using hydroponics to grow your cannabis:

  • Plants grow faster in hydroponics systems.
  • Plants tend to produce a more significant crop in hydroponics systems.
  • The gardener has total control of all aspects of the grow, amongst others.

Because nutrients are provided to plants’ roots through a mineral nutrient solution, the plant expends significantly less energy than it does seeking out nutrients from the soil. Instead of sending roots further out into the growing medium to round up their food, the root system is soaked in the solution of readily-available, suspended nutrients.

Additionally, growers use supplements such as mycorrhizal fungi and humic acid to increase nutrient uptake in plants. Supplementing plants in this manner allows them to focus more energy on growth and less on survival, generating larger plants in a shorter amount of time, with some growers reporting between 20-50% faster growth.

In addition to faster growth, growers can also expect more significant yields come harvest time. Hydroponic grows tend to produce denser, heavier and more potent buds, with some reporting yields up to 25% higher than traditional soil-grown cannabis.

Besides growing bigger and more robust plants, many growers prefer hydro growing over soil due to the simple fact that they have total control over their plant’s growing environment. Because the grower mixes and balances the reservoir of nutrient solution, they ultimately have the final say in what nutrients the plant will receive and in what concentrations. While most growers will appeal to the feeding chart from the nutrient line they choose to incorporate, the decision still ultimately rests with the grower, leaving them fully in charge of their plants.

The world of hydroponics can be a bit overwhelming because of the many different orientations and styles of grow systems that exist. Perhaps the first step to a successful hydroponics system is choosing the growing medium that is best suited for your needs.

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Types of Grow Mediums

There are nearly as many soilless mediums as there are types of hydroponic system, leaving the grower a multitude of options to choose from. The growing medium will be what the plant’s roots grab onto, anchoring the plant in place. Because hydroponic growing mediums are intended to be inert, they may retain some moisture but nowhere near the degree of soil. Soilless mediums will dry out more rapidly, causing a plant’s roots to seek out nutrients from elsewhere in the medium, thus creating a dense root system. Growers employ a wide variety of mediums, such as sand, gravel and perlite, though some of the more popular mediums include:

Rockwool

Rockwool is an industry-standard in hydroponics, created from basalt rock that is crushed and spun into a fine thread and collected into cubes. These cubes create an excellent medium for plant roots to grab onto and offer excellent aeration for roots as well. Rockwool retains water well but does not absorb it, leaving the water-based mineral solution available for plants. Because it does not absorb water, some growers feed mature, flowering plants up to twelve times a day when growing in Rockwool.

Expanded Clay Pebbles

Another widely-popular medium is expanded clay pebbles. These porous clay balls retain moisture wonderfully but also allow for rapid drainage, helping eliminate problems such as root rot. Because they’re reusable, clay pebbles have perhaps the longest life of all mediums, and once spent, can be placed into the soil or other mediums, such as coco coir, to increase aeration and drainage.

Coco Coir

Coco coir sometimes referred to as coco pith, is made of the fibre of coconuts. Ground fine, this coconut fibre takes on the appearance of a fine, rich soil, but is in fact an inert growing medium. Often mixed with perlite or vermiculite for increased aeration, coco coir is a widely-used and forgiving growing media popular with beginning growers. The presence of plant hormones from the ground coconut fibres makes it resistant to pests and infections.

The medium you choose to use may depend on the type of hydroponics system you build or purchase, with some mediums better suited for particular systems than others.

Cannabis plant grown using hydroponic grow technique

Types of Hydroponics Systems

Deep Water Culture (DWC)

One of the more common and popular methods for growing hydroponically, deep water culture setups feature a reservoir into which the plant’s roots are suspended. The reservoir’s nutrient solution remains covered, preventing evaporation, and receives constant aeration from an air pump and attached air stone, introducing oxygen into both the nutrient solution and the roots.

This constant supply of nutrients allows the roots to develop a dense structure. The reservoir is topped off with nutrient solution and water as necessary and is changed when needed. DWC systems work particularly well with expanded clay pebbles contained in a net pot as a growing medium.

Nutrient Film Technique (NFT)

The nutrient film technique (or NFT) utilizes a large-diameter PVC pipe as a conduit to channel water over a plant’s roots. Plants are suspended in a net pot placed into the PVC pipe, while a pump continuously draws water to an elevated end of the pipe where it is deposited, allowing gravity to pull it back into the reservoir. This continual flow of hydroponic nutrients along the pipe creates the visual effect of a film, giving the method its name.

Ebb and Flow

Ebb and flow systems employ pumps and trays to periodically flood a plant’s roots with oxygenated nutrient solution. Unlike the DWC and NFT systems, which continually flood the plant’s roots with water and nutrients, an ebb and flow system will use a pump (often on a timer) to fill a tray in which planting containers are placed. Once the tray has filled, the pump is disengaged, allowing the water to flow back into the reservoir, where it is continually aerated by an air pump and air stone. Ebb and flow systems are well-suited for a wide variety of growing mediums.

Drip System

Essentially a miniaturized version of a garden sprinkler system, drip systems employ pumps to push oxygenated nutrient solutions through lines to drip emitters, which are placed at the base of plants. Drip systems work well with a wide variety of mediums and can easily be scaled to fit the size of your grow. Excess nutrient solution is drained away from roots, and runoff can be re-collected in the reservoir and recycled through the drip system.

Aeroponics

Aeroponics systems employ mist valves to create an ultra-humid environment where the roots are suspended and receive constant feeding from the misters. This enables roots to receive huge amounts of oxygen and nutrient solution simultaneously, leading to rapid growth and strong root structure. Aeroponics systems are often used for the development of roots on freshly-cut clones, a technique that many believe creates stronger and healthier baby plants.

Lighting

A significant factor in any cannabis grow will be the light that plants receive. Because so many hydroponics growers work indoors, it is important to understand the amount of light that will be necessary to facilitate growth. This will depend on your grow space, the number of plants being grown, and the desired size of the plants. Growers are doing incredible things with LED grow lights nowadays, but the old standard of high-pressure sodium lights remains in place for a reason.

Putting it Together

Once all of the materials are collected, and the grow is ready to be assembled, the greatest challenge a new grower faces will be the initial setup. This may be frustrating, time-consuming, and exasperating, but once the setup has been completed, hydroponics systems possess the advantage of being easily automated, allowing the grower to worry about other factors, such as environment and maintenance of plants.

Hydroponics is a fun and easy way to cultivate cannabis at any scale. Cannabis loves hydroponics, and those who love cannabis love hydroponics, so there’s no better time to start your own hydroponic garden than now! Come check out our many resources here at Marijuana Grow Shop to assist you on your way.

Post author
Michael Richey
Michael loves to grow cannabis and write about what he learns along the way. His best friends are his dogs and marijuana.
See more from Michael Richey

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