Agriculture Resource Dive: Coco Coir

Agriculture Resource Dive: Coco Coir

Coco coir grow media pros & cons
As companies that work in the food and agriculture industry, all of us immediately take on the responsibility of ensuring that we’re leaving the food system in a better state than it was before we entered it. In order to do that, one of things we need to do is make sure that we’re informed about the abundant options of agriculture inputs that are out there. Once we have a holistic idea of what exists, only then can the controlled environment agriculture (CEA) operator choose the best option that aligns with their respective principles.

This week, we dive into one of the few compostable indoor farming grow media : coco coir

Coco coir is a byproduct of the coconut fiber industry. The outer layer of a coconut, known as the husk, is predominantly used for textiles and other coconut products. However, coco coir tends to be discarded, despite it holding a layer of usable fibrous threads. Farms realized this and therefore decided to use these leftover fibers by compacting them into bricks or sold loosely to be used as grow media.

There are two types of coconut coir. One is white coir which usually comes seeds that haven’t matured completely, which means the fibers aren’t as durable compared to those that come from older seeds. The next is brown coir which comes from more mature coconuts, making it stronger and more durable. The latter version is what is predominantly used as a grow media for indoor farming systems.

Most coco coir comes from Asia, specifically India, Sri Lanka, and Vietnam, with the largest importers being the US, China, and NetherlandsAccording to the India Brand Equity Foundation, USA is the largest importer of coir and coir products from India, accounting for 29.79% of the total value exported from India in 2021-22, followed by China as the second largest importer from India, accounting for 19.82% of the total value during the same period.

The actual process of producing coco coir is begins with coconuts going through a retting process, which is a curing method that naturally decomposes the husk’s pulp. Historically, coconut husks were soaked in water to decompose the husk’s pulp for six months or longer. However, now this process has been reduced to just over 1 week due to modern mechanical techniques. Following this, the coco coir is “defibered” by removed from the shells using steel combs. Once the coco coir is gathered from the husk, it’s then dried, pressed into bricks, discs, coir pots, or bagged as a loose mulch. The video below by Yash TV Creations provides a clear understanding of how coco coir is made.

How coco coir is extracted

Coco coir offers a strong combination of good water retention, reliable drainage, and ideal aeration. When teamed with the right nutrients, coco coir is able to reduce the amount of time that a plant spends searching for food, and thus growing. It also has a neutral pH range of 5.2–6.8, which some crops prefer. Be mindful however that cheaper coco coir that has not been processed properly could become acidic. However, nutrient support is still needed because this pH range can fluctuate over time. As a grow media, coco coir also boasts antifungal properties, allowing the roots to grow healthily. This also allows it to repel certain types of pests, making it easier for an indoor grower to maintain their system. Although coco coir is classified as an inert material, its low nutrient content is not a disadvantage compared to peat moss, as shown in the table below:

Nutrients in coco coir

From an environment perspective, indoor growers are able to help reduce the amount of waste that would have come from discarded coco coir. Harvested and cleaned coconuts may end up in our supermarkets, but all of the coco coir would have been discarded or burned, increasing our carbon problems. Furthermore, as a grow media, it is extremely lightweight due to its lack of water, as well as it being very compactable, reducing the carbon footprint from shipping due to saved space.

Coco coir can be stored for years. The downside of this is that it then runs the risk of becoming infested with pests or pathogens over time. To mitigate this, some sellers of coco coir will process it with chemicals or steam to sanitize it. However, these chemical residues can harm crop growth. For an indoor grower, knowing whether the seller has stored their coco coir properly, avoiding pests or pathogens, versus ones that have been chemically-doused is important. Avoiding those that have been manufactured using saltwater, and instead opting for coco coir that’s been soaked or rinsed out with fresh water will make a difference to crop health. Some indoor farms have seen that when there’s too much salt in the coco coir, it can deter the uptake of water by plant roots. It can also cause issues with the absorption of nutrients. Because of its high cation exchange rate, coco coir stores and releases nutrients as needed, but it tends to hold calcium, magnesium and iron. In other words, an indoor grower needs to boost their crops with those nutrients because it can get locked in the coco coir.

From an environmental and social perspective, there are certainly drawbacks. Firstly, the retting process used in coco coir production generates significant water pollution. Some of the major organic pollutants are pectin and several types of bacteria including salmonella.

Additionally, seeing as how a majority of coco coir comes from India, taking into considerations where we put our money and how that can impact an entire industry is imperative. Farmers in India still face significant challenges including no government regulations regarding how much or how little a farmer can earn.

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