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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.

Beginner’s Guide:How To Grow Weed Using Hydroponics

Growpackage Eco Farm
Oct 6, 2019 · 14 min read

What Is Hydroponic Cannabis?

The common nickname for cannabis — “weed” — comes from its ability to grow almost anywhere, unde r 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.

Advantages of hydroponics weed growing for beginners

There are a lot of benefits you acquire by hydroponics growing of the weed. The benefits of growing hydroponically include the following:

Growing hydroponic weeds ensures that the plants grow faster than with traditional methods. This is because they come in direct contact with the nutrients and can absorb more of it. Most of the experts have said that weed & cannabis plants grow 20% more quickly in hydroponics rather than in soil.

Growing weed hydroponically allows you to harvest in large quantities. Even in this case, the yields are about 20–25% more than that of the soil growth. You will need less space for each plant to grow.

Gardeners usually have a tough time cleaning up the mess caused by the overgrowth of weeds. You need to keep a check on the growth and pull out when it is in the soil. Though, this is not the case with hydroponics growing. You can’t get overgrowth of weeds in the soil because there is no soil.

Less disease and pests

Many plants are usually damaged due to the soil-borne diseases. However, with hydroponic growing, you are saved against that risk since no soil is used. The usage of soil usually caused a lot of diseases and pests which makes it tough for the gardeners to control the environment.

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.

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 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 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 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.

Choosing Your Hydroponic Garden System

Aeroponics — This method of hydroponics goes without a growing medium, although a small amount may be used to germinate the seed or root a cutting. Plant roots are suspended mid-air inside a chamber kept at a 100% humidity level and fed with a fine spray of nutrient solution. This mid-air feeding allows the roots to absorb much needed oxygen, thereby increasing metabolism and rate of growth reportedly up to 10 times of that in soil and there is nearly no water loss due to evaporation. The mist is created by special nozzles to the root system on a regular basis. The roots are held inside a water proof and light proof container which helps create a high humidity area.

Continuous flow / Top feed system — This is the system you often see pictures of. Using a 2″ or 4″ PVC tube with holes cut into the top at regular intervals for the plants to sit in a holder or pot. The nutrients are continuously fed down the PVC pipe over the root system.

Deep Water Culture (DWC) + Recirculating direct water culture systems (also known as RDWC) + BubblePonics — This is a simple yet effective way to grow, it is similar to the mist Aeroponics system in some ways. However the concept is to submerge the plants roots in the nutrient system, now without air they would die, so you add an air rock like used fish tanks. If you pump significant air through the system the bubbles maintain oxygen to the roots and they grow really well.

Drip Irrigation — A great way to save water and nutes. Used throughout large outdoor farming systems to cut down on waste, small droppers are placed right next to the stem or roots of the marijuana in their pots within the medium. Small drops of the nutrient system will drip out regularly to feed the plant. Very low evaporation and good for stealth grows too because it is silent.

Ebb and Flow — As discussed above the nutrient solution floods a tray situated above the reservoir and then ebbs back into the reservoir in the process feeding the plants with their roots situated to the tray.

Nutrient Film Technique (NFT) — Similar to the Ebb and Flow technique but it is more circular. The tray above the reservoir is tilted and the nutrients fed in from the top and let to drain in a thin film down the tray back into the reservoir, it lets roots feed and have access to air.

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 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.

Royal Dwarf presents another logical option for an indoor hydroponic setup. This strain combines Skunk and ruderalis with the aim of creating a compact plant capable of good yields and moderate potency. Royal Dwarf is sativa-dominant and offers a motivating and inspiring head high fuelled by a THC level of 13%. Each hit of this strain is infused with tastes of sweetness complemented by notes of citrus.

Expect indoor plants to reach a stealthy height of 40–70cm, produce yields of up to 200g/m², and run from seed to harvest in as little as 8 weeks.

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 hydroponic grow tents.

Hydroponic Cannabis Supplies:

3 or 5 gallon bucket (one for each plant)

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)

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…