Growing Cannabis In Rockwool 2021 | What You Need To Know! | ESTAGECRAFT

Growing Cannabis in Rockwool 2021 | What you need to know!

Growing Weed in Rockwool
(Last Updated On: December 13, 2022)

There are a number of ways you can grow cannabis in rockwool, including a number of different substrates to take advantage of. One substrate that is sometimes utilized is called Rockwool. It’s also known as mineral wool, and is essentially a type of rock that is a bit like fiberglass in the fact that it has pores and isn’t all the way solid.

It also has the ability to hold liquids to keep something moist if need be. Keep reading for information on how this can come in handy when you’re growing plants, and how to take advantage of its distinctive properties.

Growing Cannabis in Rockwool Cubes 2021

How to use it

The product is made by taking rock and ensuring that it isn’t all the way solid by heating it at very high temperatures. Essentially, it mimics lava in the fact that it makes the rock softer and able to be used for a variety of purposes.

Although this material is quite practical, it does have to be treated before you can use it, otherwise, the pH won’t be right. This is why you have to soak it for at least a day in a liquid that has the proper pH for growing plants, so that it can hold onto that value for the rest of the growth cycle.

After that happens, you can feel free to use it for whatever purpose you need.

What it’s used for

There are a number of different ways you can use Rockwool, so you should be aware of all the techniques before you start the process. Most people don’t carry out the entire progression of growing cannabis plants in Rockwool, but there are parts of the process where this material can come in quite handy.


One reason to use Rockwool is when you need to germinate seeds. Since they are able to keep the seed moist, this can be advantageous. You will still need to germinate your seeds for a few days prior to adding it to the substrate, but after that, you can place it in there to allow it to keep growing.

This permits the plant to start to develop into the vegetative stage without locking down roots. This means when it comes time to transplant the plants into soil, you can remove them without damaging any part of the plant, especially the delicate roots.

Making clones

Besides just germination, Rockwool is also used when you’re trying to make clones. It is done in the same manner where you place a young plant in it and let it grow. Then you simply take it out and place it into a more permanent home when you’re ready to.

Since there’s nothing for the roots to take hold of, they will grow but won’t become damaged, making sure they can be removed at any time.

Hydroponic growing

You can also use this material when you’re growing something hydroponically. It’s able to hold moisture and can be rinsed out and cleaned whenever you need to.

If you have ever grown anything using this technique before, you likely know that you have to flood the plants with water at least once a day or a few times a week, and you must flush out chemicals and toxins from time to time.

With Rockwool, this is quite easy to do. As a bonus, it also makes it easier to irrigate the entire grow system, which is another one of the most important steps.


This material is also a type of insulation, so you can use it to insulate any part of your operation as well. This also lets you know where you can purchase this product, if you need to buy some. You should be able to get some at home improvement stores, online, or at other specialty stores.

If you have to buy a lot of it, you will need to cut it into small squares to be able to use it. You can place these squares in plastic pots or wrap them up to use them effectively. Just be sure that you have the right type of protection for your eyes and face when you cut it, since you don’t want to be breathing in this stuff.

At hydroponic stores, you may even be able to buy small squares of it that won’t need to be cut or reshaped.

More reasons to use Rockwool

Besides helping a plant not to take root so they can be removed whenever you want, they also make sure that the pH doesn’t get out of whack. This can be especially important when you’re growing cannabis, and it will save you from constantly having to monitor the pH.

Since you took the extra time at the beginning to soak it, it’s able to keep the pH you gave it in the first place.

A system that utilizes Rockwool is easy to set up, although there are many steps to consider. You probably shouldn’t attempt to use it unless you have grown plants before. On the other hand, if you are informed about all the different techniques, there’s no reason you can’t get the hang of it with a little practice.

This isn’t necessarily for people with big gardens, as it’s better suited to growing just a few plants. This means you don’t have to have a lot of room to get started using this strategy. It can easily be done in your greenhouse, a shed, or similar.

Since this material is able to hold moisture, it can also keep the nutrients and fertilizer close to your plants at all times, which can make your products grow better and more efficiently. You might also end up using less of these products, since they will be working well.

Tips: Growing Cannabis in Rockwool

Even though Rockwool takes some of the guesswork out of growing, you still have to make sure everything else is fine; this includes the temperature, amount of light, and things like that.

You should treat it like a regular hydroponic setup if you are using it to grow your plants to maturity. Any aspect that’s not right can mess up the entire outcome, so be mindful of everything.

You don’t need to use Rockwool if you are planting outdoors, as it won’t work very well. It’s more of an inside technique, so be sure that you have a setup indoors that will work well with this substrate. Outdoor planting is better suited for soil, since it will be less fickle and you won’t have to watch it as closely.

This is a product that is unlike any other, which is a good and a bad thing. One bad thing about it is that it’s irresponsible to throw it away, since it’s not biodegradable. Do what you can to reuse it for different purposes, or find a way to recycle it.

Otherwise, it isn’t really worth using, if you don’t have a proper way to get rid of it.

Due to this substrate’s unique properties, it is impossible to overwater your plants when you’re using it. You can even leave the plants in the same piece without having to move them throughout the process.

Additionally, you’re less likely to encounter bugs when you use it, given that pests are more likely to attack plants that are rooted in soil.

While you can grow your plants their entire lives in Rockwool, most people do not. They usually transfer them to soil or something else once they are ready to hit the flowering stage.

This is a matter of preference on your part, however, and there are many ways to be sure that you’re going to yield the type of plants that you want. Read articles online and watch videos to see how some growers utilize this unique material, so you can decide for yourself how you want to use it.

It’s not only versatile, but it can be used for a number of different purposes, which makes it something that is a little special.


If you plan on growing cannabis in Rockwool, you’ll need to know what it is and how to work with it. Once you figure these things out, it isn’t really that hard to get started.

You can use this product to germinate seeds, start growing clones, or even through the entire growth process. The possibilities are endless, and this is a great thing to use if you like growing your cannabis hydroponically.

It’s easy to get the water and nutrients close to the plant and the roots will always stay healthy. Besides that, it resists bugs and will keep the proper pH when it’s been treated ahead of time.

You can’t just throw it away afterward though, so be sure to have a backup plan in place for when you don’t need it any more. Go ahead and check this stuff out to see what it can do; it may be something you want to work with for years to come.

growing cannabis in rockwool


Hey I'm Dennis, Thanks for stopping by. I'm a Horticultural Expert in growing marijuana indoors and hydroponics. I will be sharing my expertise in growing marijuana with LED Grow lights.

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