Coco Coir vs Rockwool
In the commercial and wholesale horticulture industry, many growers and cultivators are looking for solutions to gaining efficient yields without sacrificing their wallet; aka- profits! Having the solution while being eco-friendly is even better!
According to RF Agriculture – a wholesale commercial agriculture distributor – when a wholesale grower starts researching into eco-friendly options for AG, cultivation, propagation, and horticulture; coconut coir pulls up frequently as a top result. Rockwool will also appear as a popular growth medium, however, this is not an eco-friendly solution. These materials, although used with the same goal in mind, differ drastically from one another.
Coconut Coir is a natural byproduct of coconut husk as it is separated and woven into different materials such as hanging baskets, coir blocks, pots, discs, mulch, etc. This leftover material is washed and sanitized creating a durable and soft growing medium for plants that easily replicates the environment of normal soil. This material is then sold in various sizes from small scale to bulk coco coir through distributors such as RF Agriculture. According to them. coco coir has several benefits that make it an ideal growing medium for the commercial horticulture industry. “This growing medium has an increased water retention rating; meaning less water loss/use and excellent nutrient retention by cutting down on the need for nutrient applications throughout the growing season. This growing medium also deters fungal gnats and foliar diseases common of greenhouse crops,” they say. “Even though this material is biodegradable, it is durable- lasting for several growing seasons. This is ideal for a grower wanting to save on general material costs when and where applicable. Coco coir can also be used in many horticulture applications from traditional soil based growing to hydroponic systems. Due to its ideal properties, coco coir has been proven to increase crop yields while improving the production of crops grown by commercial greenhouses, CEA, cultivation, and hydroponic facilities.”
Rockwool is also known as stone wool or mineral wool due to how the material is made. Rockwool is created from melting basaltic rock down in high temperatures and then spun in a high powered vat to produce long fibers, which then get cooled by jets of air. These thin fibers are then compacted into cubes of various sizes. “These cubes are used by both commercial and small scale growers for use in a wide range of hydroponic system set ups and cultivation facilities. This material is the most widely used material in commercial hydroponic production due to excellent water retention, efficiency of water use, with excellent aeration properties allowing roots to receive adequate amounts of oxygen for proper plant growth and yields,” they continue.
According to RF Agriculture, this material also breaks apart easily, so that size adjustments can be made on the fly without the use of expensive tools. “Rockwool is also durable and will not degrade during the growing season. Furthermore, rockwool is naturally high in pH, and this should be taken into consideration if rockwool is to be used in any commercial AG operation. The high pH rating will affect plant growth along with the pH in a commercial hydroponic system. Rockwool is almost always used as hydroponic growing medium, so the application is short in the industry. Due to the material of rockwool, this is not an eco-friendly solution, as it has similar properties to that of plastic in the degradation process. It is because of this that rockwool that is no longer usable, will sit for well over a human lifetime and not decompose.”
Which Material should I use? Coco Coir or Rockwool?
RF Agriculture takes care to point out that the selection of material to use is both a grower’s preference, the application of the product, the types of plants being grown, along with general environmental conditions. “Coco coir falls under the category of loose media, while rockwool is under the category of contained media. There are three main stages of plant growth, all which require different levels of care. This should help with guiding a commercial grower in the direction of which material is the best for their specific AG application needs.”
Stage 1: Seed Germination
The first stage is seed germination. In this stage, the seeds are rehydrating, and the plantlets in the seeds are beginning to sprout. Temperature, water, and oxygen levels need to be maintained for proper plant germination to occur. Plants at this stage are delicate as they emerge from the seed. Drying out is a concern for plants at this stage, as the seed- like a sponge- requires some form of moisture in adequate amounts. The seeds also require temperatures that must typically be within a range of 75-89 degree’s Fahrenheit. A growing medium must be able to have some ability to retain warmth. During this time of rehydration, roots will emerge. The growth and health of these roots will determine the plant’s health throughout its life cycle. It is crucial to have the ideal environment for these roots to grow. This includes water, nutrients, and oxygen. This will ensure a happy and healthy plant during the entire growing season or cycle. In the first stage, starting a seed with a medium similar to soil is beneficial. According to the company, coco coir has the benefit of excellent moisture control and is able to retain nutrients while replicating a soil based environment. “With its ability to hold moisture, the seeds have a lower risk of drying out, which can cause stunting or halting growth of the seed and plant.”
Stage 2: Vegetative or Green Growth Stage
The second stage of growth is the vegetative or green growth stage. This starts after the roots have established enough to support growth. In the vegetative growth stage, a plant needs to have the support for the roots to grow so as to support the vegetative green growth of a plant. “If not supported, the plant will not grow to its potential,” the company remarks. “A plant in this stage requires higher amounts of nitrogen due to the formation of chlorophyll. Growth during the vegetative stage focuses on the formation of stem, branches, and leaves.” This stage will continue until it is hindered by a change in environment or a lack of nutrients and water. “A grower should be aware that in the early stages of vegetative growth, the plant is very delicate and requires careful handling until roots and green growth has been established. Coco coir can be used with the addition of nutrients added such as a fertilizer application specific to the crops needs. Coco coir is naturally pH neutral. This means that a grower does not have to worry of impacted plant growth due to pH increases from the growing media.”
“Rockwool can also be used in this stage through the use of larger grow cubes,” they continue. “Rockwool is traditionally used as a hydroponic media for larger plants such as tomatoes as they do very well with the larger cubes for support. After plants germinate in these cubes, the plants can then be transplanted into either soil or a hydroponic system. Care should be given to pH changes, as rockwool will begin to retain a higher pH. Periodic pH testing will need to be conducted throughout the growth cycle, more so than coco coir.”
Stage 3: Reproductive Stage
The third stage is the reproductive stage where the plants will flower and/ or fruit. The plant will concentrate all efforts on the reproduction and the continuation of the genetic line. All energies and attention is given to the production of flowers, fruits, and seeds. “Nitrogen is needed in lesser amounts,” the company explains, “while other nutrients such as potassium and phosphorus are needed in higher amounts. This is because the plant is slowing down the green vegetative growth stage focus and turning to reproduction cycle. Coco coir holds the nutrients in the soil for the plant to absorb while also providing the support needed for heavier plants in the fruit production stage. With the ability of coco coir to be neutral in nutrients and pH, the grow media can be customized to the plant’s needs at this stage.”
The Conclusion: Coco Coir
Overall the main concern for growth media is focused on the major changes in the life cycle of a plant; from seed, seedling, vegetative, flowering stages, establishing a healthy plant for maximum production, quality, and yields. Through these stages of life, a grower will need to determine the overall goals for the growing season and select a medium suitable for these goals. “For a commercial greenhouse, hydroponic, or CEA facility, the solution for budget-friendly, eco-based growing media that increases crop yields is coconut coir. This universal growing media, is a one of a kind solution to those wanting to improve their grow operations efficiently and effectively,” the company concludes.