Plants grown from cannabis (sativa or indica) are hardy and can adapt very well to different conditions, and can therefore be easily grown on almost all plant substrates. The most common methods are growing in soil or in hydroponic systems with substrates such as rock wool, coconut, expanded clay, or Mapito.
Due to the benefits of using a hydroponic system, growing hydroponic cannabis has become very popular. However, to growers inexperienced with using such a system, it may sound off-puttingly technical.
No worries, we tell you exactly how to grow hydroponic weed in your grow room, including explaining what your options are for the best hydro systems and nutrients.
What is hydroponic weed?
Hydroponic is one of the most used methods of growing cannabis and is a very old cultivation method - archaeologists believe that the Hanging Gardens of Babylon was one of the earliest examples of a hydroponic garden. There are several types of hydroponic systems, but all are based on the same principle. The idea of hydroponic growing is simple; it is based on making the nutrients available to the plants by quickly absorbing fertilizers in an inert substrate such as rock wool, expanded clay or Mapito.
How to apply hydroponic systems to your cannabis plants?
By using an automatic irrigation system, either recirculating (the hydroponic nutrient solutions are being reused) or waste-to-drain (the excess nutrient solution is not reused), the marijuana plants are optimally supplied with essential nutrients. When using expanded clay, it is imperative to stabilize the pH of the substrate to avoid problems with the pH during the grow. If the expanded clay is not stabilized, many difficulties arise for the plants, and they will not be able to absorb the nutrients sufficiently, which in turn can create a nutrient deficiency. Also, in recirculating systems, when using unbuffered expanded clay, there are fluctuations in the nutrient tank, which can also lead to over- or under-fertilization.
In recirculating systems in which the nutrient solution keeps leaving the tank and running back, the pH and EC value can be easily changed by an unbuffered or contaminated substrate. These factors also play a role in waste-to-drain systems, albeit a smaller one.
It is essential to point out that in a hydroponic setup, the plant roots are exposed to the air, and constant irrigation is necessary so that the plants can develop without problems and do not dry out. As soon as a lack of moisture stresses the plant roots, they are severely damaged because they have no protection as in Coco substrate, in which the root ball is less exposed to the air and therefore dries out much more slowly than with expanded clay. On the other hand, if these factors are under control and no mistakes are made, the growth during the vegetative stage really explodes in such a hydroponic system.
The irrigation methods of the hydroponic systems sometimes differ enormously. There are systems like the Dutch Pot, which has permanent 24-hour watering. Some growers water their plants every 15 minutes; others prefer watering them for 15 minutes every hour. Depending on the selected system, an optimal irrigation program must be set, just like when growing in rockwool.
Every grower has to find the ideal watering time for the grow, as this depends on several factors: temperature, humidity, and ventilation. If the substrate dries out quickly, more waterings must be carried out, each with the development phase and needs of the plants' optimal EC value kept in mind. In hydroponic systems with rockwool or expanded clay, the nutrient uptake of the marijuana plants is more effective than in Coco, which is why the EC value should be slightly lower. The plants must also be checked every day to find an optimal EC value for each strain.
Advantages of growing hydroponic weed
When you grow hydroponic cannabis, you will find many serious advantages. Let's dig into that deeper!
1. Complete control of nutrients and pH value
Hydroponics allows you to control the nutrients your cannabis plants need completely. Dilute them with water and add them to the tank so there is zero waste, unlike adding nutrients to the soil which is comparatively ineffective as some of the nutrients always fail to make it to the roots. You can calculate accurate nutrient measurements to guarantee that your weed plants receive exactly the right amount each day. The risk of root burn from inadvertently giving too much fertiliser is eliminated. Many cannabis strains require a correct pH value to grow properly, and again, hydroponics ensures that the guesswork is removed when it comes to testing the pH value.
2. Increased yields
The effective fertilisation leads to improved growth and maximize yields, the end goal of most weed cultivators. Your precious plants don't have to waste energy trying to get nutrients from the soil. Hydroponics means that they are free to focus on putting their energy on developing strong stalks and lovely leaves and buds.
3. A better way of using space
A hydroponic setup uses less space as the soil needs a lot of space for the roots. You can group your plants more closely together, and more hydroponic plants mean more weed, once the flowering stage begins! It's also less messy than a soil-based system, no need to spend ages sweeping spilt compost from floors.
4. The roots are visible so you can quickly diagnose problems
Observing the root system is an excellent way to spot signs of nutrient deficiency or stress as problems are usually revealed more rapidly than the parts above ground. If the roots are not white, you need to take action - brown or dark roots are only seen in unhealthy plants.
5. Speedy growth rates
Hydroponics provides direct access to the nutrients your cannabis needs, close monitoring of pH and constant oxygen supply. As long as you have adequate lighting and good temperature control, hydroponic plants will grow faster than soil plants. They are supplied with everything they need so that practically no energy is wasted. Plants which grow healthy and vigorously are also more resistant to diseases.
6. No need to worry about pests and diseases
Many pests and diseases thrive in soil. Hydroponic growing instantly offers the answer to all these risks.
Disadvantages of hydroponics
Besides the advantages of growing plants hydroponically you have to be aware of the disadvantages in order to decide if growing hydroponically is the best option for your culture. So what are the disadvantages?
1. Initial investment costs
The cost of the equipment is more expensive with hydroponic growing, than growing plants in soil. However, after several successful grows, you will almost certainly realise that the investment in a hydroponic cannabis setup is worth your money.
2. Learning curve
Although hydroponic cultivation is not difficult, it requires a solid plan of action. You learn it by doing it so take your time and enjoy the learning process
Building a hydroponic system for growing weed
The following list encompasses all the apparatus you need to build basic indoor hydroponic systems. We recommend buying each item separately at the lowest possible price, so you can reserve more funds for expensive, but essential (LED) grow lights and heating.
This is what you need
A grow space
A growing medium
Weed seeds
Mesh or net planting pots
Hygrometer to measure humidity and a thermometer
A carbon filter
LED Lights
A ventilation fan and an oscillating fan
Ducting tubes
Pump or airstone
Lighting hangers
Hydroponic reservoir and tray
Nutrients
pH and PPM meters
The best hydroponic growing mediums for growing marijuana
One of the first things you need to do is choosing a growing medium — this is a substance that supports the axis between the stem and roots. The growing medium allows the roots to descend into the water to access nutrients. There are many types of medium you can use for your hydroponic marijuana grow, each with its own set of advantages and disadvantages. It'a matter of experience to see which is best for you, no hurting in trying out what works best for you and your hydroponic gardens.
1. Clay Pebbles
Clay pebbles are highly popular as they are inexpensive and easy to use; just watch the pH levels as they may need to be altered because of the clay. Place in a basket with gaps for the plant roots to penetrate into the water.
2. Rockwool or mineral wool
Rockwool is also a common choice and is a substance made from spinning fibres from basaltic rocks into a wool texture. Rockwool is really good at retaining water, which enables proper hydration of the top root system. However, it is not very environmentally friendly and is also potentially harmful to your own health.
3. Perlite
Perlite is an amorphous volcanic glass that swells when it is exposed to high temperatures. You may have come across it in compost to prevent compaction and to provide aeration, and it serves the same purpose when used in hydroponic cannabis plant grows.
4. Coco Coir
Coco coir is the hairy fibre from coconuts and enables proper aeration and moisture retention. Coconut fibres also help protect roots from being affected by plant-stimulating hormones.
Best hydroponic system for weed
No matter which of the hydroponic methods you use, you will always need a water solution enriched with nutrients. However, some installations vary according to various factors such as circulation and water exposure. You can buy hydroponic grow setups online, or you can save money and build one yourself if you have DIY expertise.
1. Deep water culture
Deep water culture is an excellent place to start for growers who are inexperienced with growing hydro plants, and is probably the least expensive option. Cannabis plants are placed in buckets filled with a nutrient solution, and an air pump provides a constant supply of oxygen.
2. Flood and drain system
A flood and drain system (also known as ebb and flow system) This type of hydroponics system consists of several buckets hung over a growing tray which has two waterways; an inlet and outlet, both of which are connected to an external tank that contains nutrients. A flood and drain system is a very stable method of cultivation and is highly recommended for novice growers who need a secure hydro system that will still provide great results.
3. Drip system
A drip system is an active hydroponic cannabis system, which means that it utilises a pump to supply your plants with regular nutrients and water. It is also known as a micro-irrigation system. The system features small emitters to drip the nutrients directly onto your cannabis plants.
4. Nutrient film technique
If deep water culture is similar to growing cannabis plants in a pond, then the nutrient film technique equates to growing weed over a river. This system involves placing weed plants into an angled tube so that water can flow in one side and leave the other via gravity. The roots descend into the tube, where they are exposed to the flowing water. The water enters from a tank with a pump and airstone and returns once the cycle is complete.
5. Wick system
A wick system is a simple hydroponic setup that features a growing tray. A tank of water is placed underneath from which several wicks exit and enter the growing medium. Water flows up the wicks and hydrates the medium without a pump being required.
Best nutrients for hydroponics
In hydroponics, the nutrients a healthy plant need are mixed with the water the plants receive. Here you have two options, when it comes to choosing a nutrient solution:
1. Liquid food
With liquid food, the nutrient solution needs to be mixed with a certain amount of water. The plant then absorbs the nutrient enriched water, allowing the plants growing strong during the vegetative stage.
2. Capsules
The capsules are slightly different. These have to be mixed with water, but they will sink to the bottom anyway, no matter how much you mix. When the plant is hungry, it secretes a specific acid that ends up in the water and causes the capsules to disintegrate. The nutrients in the capsules are thus released and mix with the water. The nutrients are then absorbed in the same way as with liquid food. If the plant absorbs some of the water, it automatically absorbs the nutrients in the water. The handy thing about this system is that you can easily give the plant a lot of nutrients, without running the risk that the plant will immediately consume everything.
Hydroponics can seem daunting but the effort is worthwhile
Hydroponics can seem off-puttingly complex to a novice grower. All the various components and methods are a lot to take in. Our advice is to start small, select a reliable hydro weed strain, and regularly tend to the needs of your plants. Using a hydroponic marijuana system is very rewarding, and your hard work will pay off with quick harvest time and generous yields.
It's important to remember that, to produce good weed using hydroponics; it is still choosing the right cannabis seeds. You could spend lots of money on expensive hydroponics systems but fail to produce a good crop of weed. A potent strain of genetics is essential, when you grow marijuana seeds and aim to reach their potential. It will all be worth it, when they blossom into high-quality buds filled with sticky resin.
What have we learned?
When you grow weed you have many different options to approach your grow. One of the options is using hydroponic setups. With such a setup you not only automate the amount of water the cannabis plant receive, but you can also control the nutrient levels rather accurately. This can help maximize yields and your plants grow faster too. As the plant roots are constantly exposed it is also easier to diagnose any diseases.
If you want to try out your first hydroponic cannabis grow, you do have to invest in some extra equipment, and it takes some time to learn how to properly apply these method. But once you have your equipment and found the method that fits your cultivations, you might choose for hydroponic grows for the rest of your growing career.
In case you want to learn more about the art of growing cannabis, you can visit our Learning Center. You can also combine your hydroponic grow with growing techniques, learn more about those in our advanced grow guide. In case you are ready to star your next grow right now, visit our weed seeds catalog, where we offer many different varieties like our photoperiod feminized seeds and our fast growing autoflower seeds.