Stonewool Blocks in Drip Irrigation Systems

Posted on April 29, 2020 by Red Rock Block

Stonewool and Drip Irrigation: The Perfect Combo


In the commercial horticulture industry, there are many avenues a grower can go down for crop production.

One of the most common roads that they take is hydroponics. There are many benefits of hydroponics such as the versatility, conservation of resources such as nutrients and water, and the improvement of quality and yield in crops.

When selecting the medium for a hydroponic system there are many choices from coco coir, stone, clay, and stonewool.

The number one choice for a hydroponic system media is stonewool due to its many benefits and ability to integrate fully into a system with ease.

What is stonewool?

Stone wool is a natural product that has fiery origins. Before this media can be created, basalt rock is melted into a molten mass and spun into fine fibers that are then molded and packed into specific shapes for growing. Although it is made from rock, this material is very light weight and easy to work with. It is this ease of use that makes it one of the most used substrates in the horticulture industry. These fibers can be woven into plugs, slabs, cubes of various sizes and shapes, and granular products. Due to the ingredients being from minerals and rocks, this material is regarded as a natural product. Stone wool is diverse in the crop ranges from tomatoes, peppers, cucumbers, strawberries, herbs, and even flowers. Smaller operations can also take advantage of the substrate in their operations as well.

The original use of stone wool was not for the growth of plants, but rather for the construction industry as an insulation. Today it is still a commonly used insulation in construction projects around the world. It wasn’t until the late 1960’s that research was conducted to see the viability of the material to be used as a plant medium. After the tests and trials in Denmark, this material was developed and improved for better plant growth and today it is one of the top media to grow crops in both small scale and commercial operations.

What makes Stone wool so amazing? 


The way the fibers are woven and stacked, the stone wool has various shapes and characteristics. These properties range from aeration, moisture gradient, and moisture retention for crops. Through modification of the density and weaving of the fibers, various stone wool products are on the market for specific applications. One may offer drier root zones for crops that are particular in their watering, while another allows for excellent moisture retention in the root zone for the more ‘thirsty’ plants.

In the hydroponic field, stone wool has many advantages that make it the ultimate go to choice for the majority of the horticulture industry. Due to the nature of the material in which it is made and the techniques, this material is naturally sterile and free of pathogens such as insects, disease, and seeds of unwanted plants that in other media may stow away and take advantage of a perfect growing area in a greenhouse.  Well-known brands that have been built on standards and are trusted by industry professionals such as Cultilene or RedRock Block, have blocks that resist decomposition and can be reused for many growing seasons unlike many other substrates used in the industry that last only one growing season.

Stonewool is very durable and can be used multiple times over multiple growing seasons with little to no breakdowns. With the tight packing of the fibers, even with reuse, the risk of clogs in hydroponic systems are virtually nonexistent. This material is lightweight and is easy to handle and put into place. Once filled with water, however, the material becomes a strong and stable environment for a plant to grow. Smaller plugs can be used to start plants and once germinated and larger, these plugs and cubes can be transplanted with minimal stress to the plants by placing into larger stone wool blocks and slabs.  This reduces the risk of broken roots and stressed plants that can lead to stunted or slowed growth.

The material is also manufactured to give the best possible moisture and aeration levels in the root zone meaning healthy and happy root growth. The material also comes ready to use off the delivery truck. This cuts time and labor needs. There are many benefits of this material and based on the needs and goals of the operation, this material may be the perfect match!

Stonewool and Drip Irrigation: Will it Work? 

Traditional, simple hydroponic systems typically have a flood system in place to flood PVC or plastic tubing with water on a schedule. This water has nutrients as well to deliver the fertilizer to the roots and is then recirculated through the system. Drip irrigation is different in the application of water and the amounts used. It has many known benefits in traditional applications, however, not many know that this irrigation technique is an excellent accompaniment with stone wool applications as well.

One of the biggest mistakes of a stone wool system is the over-watering of plants. An irrigation method that controls the water well and doesn’t flood the blocks is one that has successful growth, development, and optimal yields. Flushing a system with nutrient solutions wrecks havoc on the plants and will reduce their ability to perform to the best of their abilities. Drip irrigation is a precise application of water directly to a root zone in set amounts either through timers or manual watering. Drip irrigation allows the grower to closely monitor and control the amounts of water being applied to the root zones of plants. Drip irrigation systems have many parts such as input controls, output controls, filters, tubing, and applicators. All of these in the system work together to apply the perfect amounts of water directly to roots zones.

Stone wool cubes, blocks, and slabs are designed and manufactured to minimize overall root disturbances while also having excellent moisture capacity. Irrigation in stone wool is slightly different than other growing mediums used in a commercial operation. Stonewool is best irrigated with short, frequent applications of solution that should be just enough to fill the moisture gradients. This is known as field capacity- where the substrate is fully drained, but still holds enough moisture for use by roots until the next watering. Drip irrigation is perfect for stone wool to meet the designed moisture requirements for plants due to its precise and low level water applications.

When using drip irrigation it is important to monitor the water content, EC, and temperature of the stonewool blocks to ensure proper water levels and fertilizer applications. This is no different than other growing media, as proper monitoring of the system is essential in knowing the needs of the plants being grown.

The use of drip irrigation and stone wool seems like a match made perfect for the commercial hydroponics industry. A grower should research their crops specific needs and gauge their goals to ensure that their operation can truly benefit from this perfect match.

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