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How to Grow Hydroponic Cannabis

How to Grow Hydroponic Cannabis

This article is sponsored by General Hydroponics, the leading innovator in the field of hydroponics for more than 35 years.

I n the previous post, we gave an overview of hydroponic gardening including its origins, the various systems and techniques, and medium options for a hydroponic grow. In this next article, we will focus how to use hydroponic systems specifically for growing cannabis.

What Is Hydroponic Cannabis?

The common nickname for cannabis—“weed” —comes from its ability to grow almost anywhere, under varying conditions and different climates. “Hydroponic cannabis” simply refers to plants grown using a nutrient-water solution and an inert growing medium rather than nutrient-rich soil. This method could be something as basic as hand-watering pots of inert medium with a nutrient solution. As discussed in the first part of this series, sophisticated systems with multiple pumps, timers, and reservoirs can take some of the daily labor out of growing, but they require more maintenance and setup time as well as a greater initial investment.

Cannabis growers have been using different hydroponic methods for many years as a way to maximize yields and speed up growth, the two main advantages of soilless growing. Working with soils indoors can be inefficient and difficult for a number of reasons:

  • You may not be able to recycle soil
  • Susceptibility to pest problems
  • Difficult to determine proper amount of nutrients
  • Need to carefully monitor soil pH
  • Soil quality significantly influences the final product

With some hydroponic methods, you get to use small amounts of grow media that can often be reused while also precisely controlling what nutrients the plants are receiving and pH levels. With such levels of control, growers find that their buds are bigger, healthier and more potent.

Whether you have grown cannabis before or have no experience growing cannabis whatsoever, hydroponics can be a great way to produce cannabis in any size space. At first it can be confusing and slightly overwhelming, but by learning the basics you will come to understand it’s not as difficult as you imagined.

Set Up Your Hydroponic Cannabis Growing System

There are numerous setups for growing hydroponically with varying benefits that were discussed previously here. And while there are several types of hydroponic setups that don’t use any type of growing medium at all, many of them still use some sort of substrate to support root growth.

Various materials all provide slightly different benefits and drawbacks, so some thought should be put into choosing the right medium for your cannabis plants. In this article, we are going to be utilizing the drip line hydroponics technique.

While this system is built from the ground up, it should be noted that there are plenty of plug and play systems available for those looking for something that is easy to set up. Plug and play systems come with everything you need in a streamlined package to allow growers to get started on the right foot.

First we will start with the supplies needed. Keep in mind this is just an example, and depending on your space and desired results, many things can be tweaked in a hydroponic system to make it most beneficial to you. This list specifically outlines equipment needed to install your hydroponic system and does not include lights, fans, filters, and other basic needs for any grow room.

Hydroponic Cannabis Supplies:

  • 3 or 5 gallon bucket (one for each plant)
  • Grow table
  • Clay pellets (enough to fill each bucket)
  • Rockwool cubes (one 1.5-inch starter plug per plant)
  • Reservoir tank (depending on the size of garden)
  • Water pump (the bigger the better)
  • Air pump
  • Air stone
  • Plastic tubing
  • Drip line
  • Drip line emitters (one or two per plant)

Browse Hydroponic Growing Supplies

Once you have gathered your materials you can begin to construct your hydroponic setup.

  1. First, set up your reservoir. Your reservoir is where your nutrient solution is held. A reservoir can come in all shapes and sizes depending on your grow space and size, and it holds the water pump and the air stone. It will have a line in from the air pump to the air stone and a drainage line in from the grow table. The reservoir will have a line out from the water pump to the drip line and the power cord for the water pump.
  2. Next you will create your grow table. The purpose of the table is to contain and return the excess water from the plants to the reservoir. To do this successfully, the table needs to have a low point where all the excess water will travel to. This low point is where you install the drain that will take the water back to the reservoir via plastic tubing.
  3. You can then add your 5 gallon buckets filled with clay pellets on the table. Before using clay pellets, you should soak the pellets overnight to allow them to become fully saturated with water for your plants to drink. Also, the buckets need to have holes drilled in the bottom to allow them to drain excess water onto the grow table. It is important that the holes are about half the diameter of the clay pellets to prevent the pellets from passing through or clogging the holes.
  4. Take the plastic tubing coming off of the water pump and run the line to the grow table. From here you can use drip line equipment to puncture holes in the plastic tubing and extend drip line to each bucket. Finally, attach drip line emitters to the end of the drip lines.
  5. From here you can run your system without plants to see if everything is functioning properly. The system should not have standing water anywhere. The air pump should always be running to keep the water in the reservoir oxygenated and moving, while the 5 gallon buckets and grow table drains any excess water back into the reservoir.
  6. At this point you are setup and ready to create your nutrient water solution in your reservoir. Below we will introduce information about nutrients and how to use them to grow your cannabis plants.
  7. Once your solution is ready, can introduce your plants. Take the starts or clones that have begun growing in rockwool and place them into the clay pellets. Insert the drip line so that moisture is reaching the rockwool and roots of your starts.

A benefit this setup offers is that it can easily be expanded as you want to grow more plants as long as your reservoir has enough capacity to provide all the plants with enough water. To expand a drip line setup, all you need to do is add additional lines to the new pots.

Nutrients for Hydroponic Cannabis

When growing hydroponically, you are responsible for providing all of the nutrients necessary for plants to survive. Nitrogen (N), Phosphorus (P), and Potassium (K) are the three essential nutrients for plant growth known as macronutrients. Additionally, there are secondary and micronutrients that will help the plant develop as well. These include Boron, Calcium, Copper, Iron, Magnesium, Sulfur, and Zinc.

Many companies sell hydroponic nutrient solutions that are specifically designed for certain stages of growth. Nitrogen-rich nutrient solutions will be used in the vegetative stage while phosphorus-rich nutrients become more necessary in the flowering phase.

Nutrients will come either pre-mixed in a solution or in powder form. While powder form might be cheaper and less bulky, it is best to stick with liquid pre-mixed nutrients if you are a small-time grower as they mix with water easily and are more forgiving.

Explore Nutrients for Your Hydroponic Cannabis

When mixing in nutrients, take a few measurements to make sure your solution is safe for the plants. First, make sure you have the right EC (electrical conductivity) reading, and secondly, ensure your pH reading is correct.

The EC reading is how growers can tell how strong their solution is, and how mineral-rich the water is. The more minerals, the higher the EC rating will be. Generally speaking, a reading between 0.8 to 2.0 is appropriate for growing cannabis. When a plant is young, it will need a lower amount of nutrients as opposed to when it is flowering and growing quite big.

Another common measurement used is ppm (parts per million) which is another way of looking at how nutrient-dense your solution is. There are two different scales for ppm used in the cannabis industry: the 500 and the 700 scale. The most efficient way to determine ppm is to take an EC reading, multiply it by either 500 or 700 depending on the scale you are using. An EC reading of 2.0 would equal either 1,000 ppm (500 scale) or 1,400 ppm (700 scale). Many readers used to measure EC or ppm will do this conversion for you.

The lower the ppm, the less nutrient-dense a solution is. As a general rule, aim for the following densities based on your plant’s age:

  • Seedlings/early sprouts – 100 to 250 ppm
  • Early vegetative stage – 300 to 400 ppm
  • Full vegetative stage – 450 to 700 ppm
  • Early blooming stage – 750 to 950 ppm
  • Full mature bloom/ripening stage – 1,000 to 1,600 ppm

Note what scale the nutrients you are using are based upon before making any nutrient solutions.

Next, you’ll need to balance the pH level. Between 5.5 and 6 is ideal for cannabis to absorb the nutrients. If levels are off significantly, the plants will fail to uptake the nutrients and will suffer deficiencies.

You should continue to monitor your solution by taking readings two times a day to make sure everything is at the correct levels. Regardless, it is good practice to switch out your solutions every week or two to keep the solution as optimal as possible.

Caring for Cannabis Grown With Hydroponics vs. Soil

Raising a plant with hydroponics is different in many ways from growing in a soil garden. One thing to consider is the support the plant is receiving. Unlike a plant growing in soil, plants in hydro mediums might be vulnerable to tipping or breaking. Trellising your garden will help to prevent this from happening and will also allow you to train your plants to grow in specific directions.

Another thing to consider is pruning. With hydroponics, your plants can grow extremely fast. This means you need to be diligent about pruning. Removing all the bottom foliage and topping your plant before switching to its flowering cycle will allow your top colas (the large, topmost buds) to receive all the energy they need.

Growing hydroponically does require that you invest a good amount of time and money into developing your system prior to actually starting your garden. Additionally, you’ll want to make sure your system works effectively and your nutrients are high quality so that your plants will flourish. Once you gain a knack for hydroponics, you’ll be on your way to producing world-class cannabis that is well worth the effort.

Have you ever tried hydroponic growing techniques before, either for cannabis plants or other grows? Share your advice, tips, and questions in the comments section below!

Learn how to best use hydroponic growing systems and techniques to cultivate cannabis and how these techniques can improve your crop.

Hydroponics Cannabis Growing Guide

Hydroponics is a method of cultivating plants, specifically cannabis in this case, in a solution of water and nutrients.

Contents:

As the name may suggest, hydroponics is a soilless method of growing cannabis using water as the primary medium. Within a hydroponic setup, cannabis plants are grown in buckets or baskets filled with an inert growing medium, and are suspended over a tank full of water. The water is filled with all of the nutrients plants need to survive and thrive, and air stones are used to aerate the tank. This basic model manifests in many different forms and systems, with different growers preferring different setups. There are many advantages to hydroponic cultivation, all of which will be covered in this article. But first, let’s delve into the history of this fascinating art form.

THE HISTORY OF HYDROPONICS

Hydroponic cultivation might initially seem like the result of modern advances in technology. But this couldn’t be further from the truth. The origins of growing plants in water goes back thousands of years into human history. The famous Hanging Gardens of Babylon, created in 600 BCE, are theorised to have utilised hydroponic principles. The region located next to the Euphrates was naturally dry and arid. It’s believed the crops of the garden were nurtured using a trickle-system starting at the river.

Moving closer in time to the 10th and 11th centuries, the Aztec civilisation was also known to utilise hydroponics to provide sustenance to their society. After being forced from their land via conflict, these people settled at Lake Tenochtitlan. They proceeded to build floating rafts topped with soil, allowing crops to grow through the tap layer and spread their roots into the waters below.

More recent, but still distant, examples of hydroponic growing involve the English scientist John Woodward in 1699. His work involved cultivating spearmint plants in water. He found that the plant species grew faster within a water source mixed with soil.

The history of hydroponics has shown how effective this method can be in many different settings and scenarios, with cannabis cultivation being no exception. Let’s explore the advantages of this interesting method, and how to apply it to growing great weed.

THE ADVANTAGES OF HYDROPONIC GROWING

If you talk to a grower who has experience with hydroponic growing, one of the first things they’ll probably tell you is that their hydroponic plants grow much, much faster than those in soil. This is a prime advantage of this method of cultivation—hydroponic plants usually grow 30–50% faster and often provide larger yields. A large reason for this is that nutrients within a hydroponic system are much more readily available to plants. The nutrients are suspended in water and enter directly into the root system as there is no soil to navigate through. In contrast, plants growing in soil must search through the medium in order to uptake nutrients from below. Easy access to nutrients allows plants to preserve energy, which is then diverted to growth efforts instead.

MATERIALS NEEDED TO MAKE A DIY HYDROPONIC SYSTEM

If you go the DIY route, check out the brief guide below. The list covers all of the equipment you need to construct a basic indoor setup. Simply find the product that suits you for each listed item. Buying your gear separately allows you to invest more heavily into important items such as lighting while reducing the cost in other areas.

Here’s what you’ll need:

a) Lighting (LED or HPS)

b) Lighting hangers

d) Hydroponic reservoir and tray

e) Airstone and pump

f) Growing medium (e.g. coco coir)

g) Net mesh planting pots

i) Ventilation fan and ducting tubes

j) Carbon filter

k) Oscillating fan

l) Hydroponic nutrients

m) pH and PPM meters

THE COST OF GROWING WITH HYDROPONICS

When thinking about hydroponics, you might picture a high-tech setup: automated switches, flashing lights, ticking timers. However, the cost of a hydroponic system all depends on how much money you’re willing to splash. They range from a simple plastic bucket all the way to self-draining and flooding systems. To save time, invest in a cheap hydroponic starter kit. These include all of the materials you need to get from seed to harvest. You can purchase one for around £200 (€235).

1. CHOOSE A GROWING MEDIUM TO GET THINGS STARTED

Now that we have covered the history and benefits of hydroponic growing, it’s time to get things started. To begin, you’ll need to select a growing medium—a substance that will hold in place the intersection of the stem and roots. From this location, the roots will grow down into the water in search of nutrients. The inert medium also allows good air access to the top of the roots. There is a huge list of different media used by cultivators, with those below being the most common. Each medium has its own unique benefits, and some work better with different systems. It’s all about experimentation when starting out to see which works best for you.

  • CLAY PEBBLES

As one of the most popular options, clay pebbles are excellent at aerating root systems. Clay pebbles sometimes require that growers alter the pH in order to provide an optimal growing environment, however, pre-altered pebbles can be purchased. You’ll need to place clay pebbles into a plastic hydroponic basket that has spaces for roots to grow through.

As one of the most popular options, clay pebbles are excellent at aerating root systems. Clay pebbles sometimes require that growers alter the pH in order to provide an optimal growing environment, however, pre-altered pebbles can be purchased. You’ll need to place clay pebbles into a plastic hydroponic basket that has spaces for roots to grow through.

  • ROCKWOOL

Rockwool is another popular choice, and is a substance created using volcanic rocks with a wool texture, hence the name. Rockwool has a tremendous capacity to retain water, which allows for good hydration of the upper root system. Rockwool can be placed within a hydroponic basket, but can also be lodged directly into the top of a bucket or tank lid without.

Rockwool is another popular choice, and is a substance created using volcanic rocks with a wool texture, hence the name. Rockwool has a tremendous capacity to retain water, which allows for good hydration of the upper root system. Rockwool can be placed within a hydroponic basket, but can also be lodged directly into the top of a bucket or tank lid without.

  • PERLITE

Perlite is a volcanic glass that expands when exposed to high temperatures. It’s often used in garden soils to provide aeration, which is exactly why it’s beneficial to use as a hydroponic growing medium for cannabis.

Perlite is a volcanic glass that expands when exposed to high temperatures. It’s often used in garden soils to provide aeration, which is exactly why it’s beneficial to use as a hydroponic growing medium for cannabis.

  • COCO COIR

Coco coir is a good sustainable option for a growing medium. As the fibre from coconuts, coco coir allows for good aeration and moisture retention. Coconut fibres are also known to protect roots from infection due to the presence of plant-stimulating hormones.

2. CHOOSE A HYDROPONIC GROWING SETUP FOR YOUR PLANTS TO THRIVE IN

Now that you’ve selected a growing medium, it’s time to choose which type of hydroponic setup to use. All systems are similar in that they utilise a nutrient-enriched water solution. However, setups can vary widely depending on factors such as water exposure and circulation. Most of the following systems can be purchased, but those with DIY skills could easily make them by using buckets, drills, pumps, and air stones.

DEEP WATER CULTURE

Deep water culture is a good place to start for beginners, and is likely the cheapest option. Plants are placed in buckets filled with a nutrient solution and an air pump provides a constant supply of oxygen.

EBB AND FLOW

An ebb and flow (also known as flood and drain) system features water that, well, ebbs and flows. These systems consist of several buckets suspended above a growing tray that features a water inlet and outlet. Both of these waterways are connected to an external tank that contains nutrients, an air stone to aerate the water supply, and a pump to move water into the growing tray. The roots in these systems are not continuously submerged within water. Instead, water periodically floods the growing tray with fresh oxygen and nutrient-enriched water. Once the pump cycle ends, all of the water drains back into the external tank.

This system allows for periodic feeding. The time when the growing tray is empty allows growers to easily tend to plant roots and harvest plants.

DRIP SYSTEM

A drip system in hydroponics is very similar to a drip irrigation system when growing in soil. This system consists of a large tray filled with growing medium, such as clay pebbles. Plants are placed directly into the medium, and each has its own drip pipe nearby. An external water tank with a pump and air stones constantly supplies a drip feed of water over each plant. The roots of these plants are constantly exposed to air, and the excess water drips down the medium and back into the external tank.

NUTRIENT FILM TECHNIQUE

If deep water culture is the equivalent of growing cannabis plants in a pond, then the nutrient film technique is the equivalent of growing weed over a river. This system involves placing plants into a tube that is angled, so water can enter at one side and exit at the other via gravity. The roots grow down into the tube, where they are exposed to the flowing water. The water enters from a tank with an air stone and pump, and returns back once the cycle is complete.

WICK SYSTEM

A wick system is a basic hydroponic setup that uses a growing tray similar to the drip system filled with clay pebbles. Under the tray is a tank of water, from which several wicks exit and enter the growing medium. Water travels up the wicks and passively hydrates the medium. No pump is required for this system.

AEROPONICS

Aeroponics is perhaps the most futuristic version of hydroponic growing, and uses misted water dispersed through the air to optimise aeration and hydration. Plants are placed into the top of a large tank of water filling the bottom 25%. Under the water is a pump that sends water into misters underneath the root systems. This fine mist constantly soaks the roots, allowing plants to receive massive quantities of air and water simultaneously.

3. PREPARE YOUR SYSTEM TO ENSURE A SUCCESSFUL GROW

After choosing your system, it’s important to prepare it well to prevent any detrimental situations. The damp and dark nature of water tanks is an ideal growing environment for a host of pathogens. Before running your system, you will need to sterilise your equipment to minimise the chances of contamination. Wipe down all of your buckets, trays, pipes, and tanks with rubbing alcohol, hot water, and peroxide. Once your system is sterilised, begin following the instructions to set it up correctly.

YOU’LL NEED TO MAINTAIN YOUR SYSTEM REGULARLY

Every hydroponic system requires frequent maintenance to provide an optimal growing environment. Below are all of the major factors you need to be aware of.

A) ALWAYS MONITOR PH

You’ll need to constantly test the pH of the water to ensure an optimal growing environment. Nutrients are more available to plants when the environment is slightly more acidic. Therefore, a pH of 5.5–5.8 is required. Use a pH testing kit to take regular readings, and be sure to change the solution weekly to maintain this range. During flowering, a pH of 6 is preferred.

B) TRY TO KEEP YOUR WATER TEMPERATURE AT AROUND 20°C

Hydroponic cannabis has an ideal temperature of 20°C. This factor can be monitored using a water thermometer and altered using a water heater if the temperatures are too low.

C) PROVIDE THE CORRECT QUANTITY OF NUTRIENTS

Hydroponic plants require the same nutrients as their soil-based counterparts. The easiest way to go about feeding your plants is by purchasing hydroponic nutrient solutions that contain all of the required substances for both the vegetation and blooming periods. Products will also describe how often to add nutrients back into your system and how much dilution is required.

D) KEEP THINGS CLEAN TO AVOID CONTAMINATION

Both growing trays and tanks require emptying and cleaning around every two weeks. This process will keep the roots of your plants safe against invading pathogens and diseases. Repeat the same process mentioned above when initially preparing your system.

E) SELECTING A STRAIN FOR HYDROPONIC GROWING

Strain selection is an important factor of hydroponic growing. Plants grown within these systems are free to uptake nutrients extremely fast, which often results in explosive and rapid growth. For this reason, selecting a large, towering sativa variety won’t be your best choice, especially if your system resides within an indoor grow tent.

Smaller and more compact strains are ideal for indoor hydroponic systems. Beginning with a smaller strain is advantageous for several reasons. For one, it will let you cultivate several plants within a smaller space, allowing for more diversity and potentially bigger yields. Additionally, if your plants do go through a growth spurt, you’ll have room to deal with such sudden surges in height.

Below are two strains that we recommend for hydroponic growing.

WHITE WIDOW

White Widow is a perfectly balanced hybrid strain that features 50% indica genetics and 50% sativa genetics. She was created using parent strain White Widow S1, and provides a well-balanced high that stimulates and excites the mind whilst relaxing and stoning the body. A THC level of 19% ensures a powerful psychoactive experience that lasts several hours. These flowers contain a terpene profile that emanates grounding tastes and smells of earth and pine.

White Widow will reach a height of 60–100cm when grown indoors, making her an ideal candidate for the spatial demands of a hydroponic growing operation. Expect good yields of 450–500g/m² after a flowering period of 8–9 weeks.

Hydroponics is a method of cultivating plants, specifically cannabis in this case, in a solution of water and nutrients.