Can You Use Rockwool Insulation for Hydroponics?

Out of many necessary ingredients, growth substrates are a crucial part of hydroponic technology.

Insulation is one of the most tricky parts of hydroponics. As a result, smart gardeners are always looking out for cheap alternatives.

Many of them end up with the artificial product made out of rocks and sands are known as Rockwool insulation. They are very similar to those used in home constructions and growth substrates for the plants by many gardeners.

I would say, smart choice indeed!

Yes, you heard it right; they are often used in hydroponic systems to regulate the demand of substrates for plants to culture.

A detailed hydroponically usage of the Rockwool insulation is left in this article.

Can You Use Rockwool Insulation for Hydroponics?

Yes, Rockwool insulation can be more or less used in hydroponic systems to regulate the same. But, the guaranteed outcome from Rockwool insulation may be lesser compared to the hydroponic Rockwool.

To use the Rockwool insulation in your hydroponics, you first need to have a clear idea about it. With that said, they are growing substrates required in the hydroponic system for the growth and development of plants.

Rockwool insulations are made from basaltic rocks. They are the molten form of stones manufactured by spinning them into fine fibers.

This fiber is used as blocks, cubes, granular products, and growing slabs. They are also known as the essential substrates for hydroponics.

Now that you know about them, you should also interpret that they can equally grow your plants hydroponically.

The reasons behind which you can use or should use them are many. Among them, their availability becomes a crucial part.

Rockwool insulations are something that is so much readily available. You can almost find them everywhere, including a hardware shop.  While, in terms of hydroponic Rockwool, you may require them to order online.

Again, Rockwool insulations are comparatively cheaper. So, you may not find practical reasons not to use them!

Hydroponic Rockwool vs. Rockwool insulation, Which is Better?

In growing plants hydroponically, substrates come to be a crucial ingredient out of many other such required things.

Rockwool insulation and Hydroponic Rockwool are two such components used as substrates in this process. But, for the best outcome and results, one needs to be careful with every small matter. So it also goes for both of them when they are selected as the growing mediums for your plants.

It is not at all acceptable to make your plants suffer from the new growing media without seeing the impact caused by it. And, many times while selecting the media, people get confused about choosing between them.

To solve this, today we have come with some presentations to know which is better for you.

Presence of added chemicals

Among many differences, one of the fundamental differences between Rockwool insulation and hydroponic Rockwool is the presence of chemicals. There is a different rate of added chemicals that remains in both of them for performing their tasks.

In Rockwool insulations, there is an excess of these added chemicals to make them fire-resistant. This purpose is actually to make them eligible for home use.

But, this presence of excess chemicals can threaten your plant’s life in some cases.

You can comparatively find fewer chemical additives in hydroponic Rockwool, specially made to suit the hydroponic system.


The first thing that may hit your mind is that they work are preservatives when it comes to formaldehyde. Although you are not wrong, besides preserving foods, they are also used for other purposes.

In Rockwool insulation, this chemical is used for binding. But, after the job, it is removed. However, this doesn’t mean that you can completely get rid of it. Which is to say, it remains with some of the traces on the Rockwools.

As numerous blocks of these insulations are used for the plants, the action of this chemical also increases. As a result of which, the growth of your plant’s decreases.

This decrease in growth can lead up to 27% and 5% to reduce water storage. Besides this, the intake of such plants can also cause many side effects like irritation of the throat, nose, eyes, etc.


The usage of asbestos is banned in Rockwool for its increased chance of causing cancer. So, you cannot generally find them now on any of your Rockwool.

But, around the country, especially in the old homes, you can still find their traces that are harmful to you and the plants.

The nutrients level throughout the leaves of your plants is reduced. A result of which is the reduction of the plant’s growth. Plants’ growth is stunned due to this.

The intake of such plants can also cause skin irritation in humans.

With all that being said, you cannot individually select which is better than the other. The fact depends on the individual’s perspective.

If you want to go through more availability and economical way of cultivating, you can go for the Rockwool insulation. But, again, if you are ready to invest the best out of yourself for minimizing the negative impact on your plants, don’t hesitate for the hydroponic Rockwool.

But, the best selection would be the hydroponic Rockwool. According to its naming, it is made to serve this hydroponic system.

Growth of the Plants Using Rockwool Insulation Hydroponically

Despite this material’s availability, you would not find the best outcome once you use them in your cultivation.

The results and the outcomes may start to get compressed if you go exploring with the Rockwool insulation. There is hydroponic Rockwool to sustain this system; people also become eager to go with the Rockwool insulation found in the local shops.

But, in actual they are not suggested for your plants as they overall decrease the rate of growth of the plants. You’ll start to see the immediate consequences right after implementing them on your plants!

What are the Treatments for Rockwool Insulation to Make them Eligible for Use?

As told before, Rockwool insulations are not the right way to go with your hydroponic cultivation. But, when you don’t have an option or a choice at the cultivation time, you need to pick them anyway.

For this, you have to aid them with the proper treatments that can help your plants to grow to minimize the side effects

Proper washing of the insulation

The best way to wash out the chemicals from Rockwool insulations is to wash them out! Proper washing of the insulations includes some reasonable steps.

To wash them ideally, soak them in the solution of detergent and water. Keep them for 24 hours inside the answer until they drink the solution thoroughly. As a result, chemicals inside these insulations will be removed to their extent.


Rockwool’s is the best holder of water. That is to say; water storage is relatively high in them. But, in the case of insulations, they do not store as much water as the hydroponic Rockwool.

Soak them in a bucket full of water. They should be soaked until a single bubble in the water prevails. As a result, these will serve the plants with great content of water for their growth.


Sterilization also becomes a crucial factor in the case of using Rockwool insulations for your plants. In this process, they are made free from bacteria. This process is mainly done for reusing them.

Hydrogen peroxide is best in terms of sterilizing them. To resist any disease and infections, this method is supreme. Particles of impurities are removed through this.

Adjustment and balancing of the pH levels

The other most essential factor in the growth of any plant is the pH level. The pH level of the insulation will also affect the pH level of the whole system.

Rockwool insulation has a pH level of 7.8. This makes them a primary compound. But, the pH level of the solution of growing plants cannot be essential. They need to follow a neutral condition.

As a result, the pH level of the insulation should be dragged back to the line. This can be done by soaking them in pH adjusting solutions.

Cutting of the Rockwool insulation

Cutting of the insulations is essential as they also contribute to the growth of your plants. Therefore, not only the type of Rockwool but also the size of them also matters.

It is essential to ensure the placing of your plants on the blocks of insulations. Rockwool remains in the form of small and more significant cubes. They also tend to change their shape.

As a result, they should be cut so that a sustainable situation for your plants is built. Again, they should have an outer covering with paper so that their shapes are maintained.

Final Words

Rockwool can be a smart insulation option for hydroponic vegetable growers (Link: Easiest plants to grow Hydroponically). It offers a lot of options along with a lower price tag. Remember, insulation plays a central role in maintaining optimal growth in aeroponics and hydroponics techniques.

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