How Cultiwool offers the highest stone wool quality in the international market

For the last couple weeks the international horticultural industry has been through some trust issues and heated discussions, around the lower quality stone wool offered in the market by multiple companies. Many growers are experiencing abnormal growth morphology similar to how a fern might appear and even worse crop loss. Cultiwool always dedicated time to show how much quality matters to us, and what we do to maintain the highest quality possible. This article elaborates on what can make or even break a high quality horticultural stone wool and what growers should be looking for.

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Cultiwool helps you and your plants grow. We do this by combining European quality, innovation, and knowledge in a complete range. We focus on stone wool products of the highest quality with an eye for the smallest detail. At Cultiwool we have engineered our products (plugs, blocks, and slabs) in such a way as to fit the cultivation requirements of medicinal plants along with innovative features like the 'donut ring' and cross groove drain pattern. It is important, especially because of the unique aspects of a medicinal plants’ production; uniformity and hygiene/cleanliness.

High-quality stone wool vs. slag wool

In light of the current situation, we think it is important that you know that not all stone wool is created equal and there are several contributing factors as to why. This is the difference between high-quality stone wool (mineral wool) and slag wool.

High-quality stone wool like Cultiwool consists of volcanic rock, typically basalt. Stone wool is a furnace product of molten rock at a temperature of about 1600°C, through which a stream of air or steam is blown. More advanced production techniques are based on spinning molten rock in high-speed spinning heads like the process used to produce cotton candy.

Slag wool is produced in a similar fashion but uses a different material to create fine fibers. Slag wool is made from blast furnace slag, a waste byproduct of steel production. No need to say that this can never result in a homogeneous product. The industry estimates that over 90 percent of the slag used for stone wool is purchased directly from steel manufacturers. The remaining 10 percent is mined from waste disposal sites and landfills.

Preventing your plants from heavy metal contamination

A large concern for growers, when understanding the differences between high-quality stone wool and slag wool, is the possibility of heavy metal contamination utilizing a slag wool material. With increasingly strict measures being placed on heavy metals and medicinal plant products, growers must minimize all possible risks of contamination. At Cultiwool we highly value the importance of safe substrates. That is why we only use top-quality European stone wool: the best available. The stone wool used in the Cultiwool products is certified by RHP and all products meet the highest requirements related to heavy metals set by the horticulture industry.

Are you interested in conducting a trial with Cultiwool? Fill in the contact form on this page and we will get in touch with you. Also, if you have any questions regarding our stone wool products. Feel free to contact us.

Specialized production for consistent quality

It is essential to research products and their companies in the increasingly completive market, focusing on their production processes. Proper research and inquiry can save money and time, but most importantly, the crop and your investment. Stone wool and slag wool, commonly used for building insulation and soundproofing, are both highly fire-resistant and can be customized in terms of air space and shape. These hydrophobic materials resist moisture degradation, and their properties can be adjusted during manufacturing for specific uses like horticulture. Understanding these aspects is crucial, as they can reveal potential inconsistencies and imperfections in these products. This is what also makes stone wool an ideal substrate for horticultural purposes but must be dialed in.

The importance of homogeneity

In horticultural stone wool, especially for propagation involving delicate materials like cuttings, seeds, or tissue cultures, product homogeneity is crucial. It ensures equal growth conditions for plants in different stone wool plugs or blocks, making homogeneity a key differentiator between high and low-quality stone wool. Achieving this requires high-tech machinery, an experienced team, and high-quality starting materials. Many stone wool producers do not have a dedicated machining line for horticultural products. Not every stone wool-producing company can meet horticultural standards, leading to significant variability in product consistency among manufacturers. In horticulture, small functional details can greatly impact outcomes; both positive and negative. At Cultiwool, we prioritize these details and consistently maintain high quality in our products, as stone wool is fundamental to all our growing mediums, making its quality and consistency vital.

Stone wool & wetting agents

As mentioned previously, stone wool and slag wool are both hydrophobic materials. This means that a wetting agent must be applied to the stone wool products to maintain their near-perfect water-to-air ratio.

Surely you are already aware, that not all wetting agents are created equally. Lower-quality wetting agents can lose effectiveness over time reducing the blocks’ water retention capacity. This also brings up the importance of how this wetting agent has been applied to the fibers. One test in which we recommend is the soaking test. One thing you notice with Cultiwool is how quick the block will sink when placed in a bucket of water. A lot of lower quality slag wool and even stone wool will tend to float on water even sometimes requiring the grower to physically submerge the block in order to achieve saturation.

This test alone will show how consistent a wetting agent has been applied. Naturally, the wetting agent is pulled down through gravity but how it is applied can minimize this and reduce the chance of excessive channeling. In more simple words, the wetting agent is especially important at the first initial saturation of the stone wool products. Full saturation is crucial in order to minimize dry spots throughout the plants life cycle which is key to utilizing the total volume of your stone wool. This also gives more control with precise crop steering techniques.

Certified stone wool to maintain an ideal root zone environment & drive quality

A consistent product can allow the grower to optimize efficient watering and nutrient use, minimize excessive channeling, and create an ideal root zone environment. This leads to more consistent crop steering techniques and efficient dry backs to influence and drive quality. Using sensors, growers can control these features knowing they are working with a consistent product allowing for more precise control. Cultiwool is changing the standard of quality and consistency when it comes to stone wool and cultivations are noticing. Cultiwool is the RHP-certified substrate that upholds the strictest standards when it comes to high-quality horticultural materials.

About RHP certification

RHP has been the European knowledge center for growing media since 1963. With the RHP quality mark, you increase the security that the substrate complies with the quality requirements concerning, for instance, water uptake, air content, pH, EC, and nutrients. It also offers more security in that the substrate is pure and clean and that it can be used without risks to the cultivation. The RHP quality mark monitors the quality of growing media in the chain, from raw materials production to processing and delivery at the company of the user.

We would like to help you

We know we can provide you with the best stone wool available on the market. And we would love to show you. So, please feel free to get in touch with us. No strings attached. Questions, remarks, samples, and trial requests; all are welcome. Fill in the form below to let us know how we can help.