Once tossed aside in the production of all things coconut-related, coconut coir (or coco coir) has become a go-to amendment and growing medium in recent decades.  Many cannabis growers, and gardeners in general, have adopted coco coir for its unique utility and versatility.

Coco coir is the fibrous inner layer of a coconut's husk, providing the bulk of the protection for the inner flesh and milk that we love so much. 

After it's separated from the flesh and milk, a usable product is made by soaking, aging, and processing the coir. Like any growing medium or amendment, quality varies from product to product. Buying from a manufacturer that has properly harvested, prepared, and processed the coir is important.

Coco coir is a versatile tool in any grower's toolkit since it can be used for both soil-based and hydroponic grows. 

In soil, it's often used as an amendment. Coco coir adds structure to the soil by holding onto water while also helping to keep roots aerated. It is a popular alternative to peat moss, with the added environmental benefits that it's a quicker-growing renewable resource and a natural by-product of coconut production.

Coco coir can also be used as a hydroponic growing medium. Because it looks and feels like soil, coco coir is often recommended to growers who are new to hydroponics

How to use coco coir

There are different sizes and textures of coco coir products available, each with its own uses:

  • Coco peat (or pith). A very finely ground coir material that behaves much like peat moss, but unlike peat, it has a longer life since it can be reused. On its own, coco peat is so fine and absorbent that it would smother roots.
  • Coco fibers. Long slender ropes of coir material. These fibers aren't very absorbent and function to create needed air pockets in the growing medium. They do break down over time and need to be replaced.
  • Coco chips. These can be used as a clay pellet alternative. They create structure in the medium while also retaining water. They can also be used as mulch or a top layer.

While you can find each of these sold on their own, most coco coir products are a mixture of these three to provide optimal results as an amendment or medium.

You can buy ready-to-use coco coir products at your local home and garden center, though it's more often sold as tightly compacted dehydrated bricks that require rehydration before use. Because coco is so good at absorbing and retaining water, these bricks multiply into considerably more usable medium, making it much more cost-effective than buying ready-to-use.

When using it as a soil amendment, a standard rule of thumb is to make about 30% of your mix coir. 

If you're using coir as a hydroponic medium, follow standard hydroponic feeding procedures since coir is an inert medium that offers no nutrition to your plants. There are hydroponic fertilizers made especially for growing in coir, and these coir-specific products will have calcium and magnesium (often referred to as “cal-mag”) added to the formula since coir tends to not retain these minerals very well. In addition, most growers add perlite (about 30% of the mix) to coir for optimal results. 

Pros of coco coir

Coco coir has become a very popular tool in both the commercial and home gardener's tool kit since it's so versatile. There are many pros for using coco coir for growing cannabis, including the following.

It offers the benefits of both soil and hydro.

Coco coir offers the best of both worlds: it looks and feels like soil while offering the speedier growth and healthier root systems associated with hydroponic growing. A coco coir-based garden is also generally less expensive than a classic hydroponic system.

It has very high water retention.

Coco coir can retain up to ten times its weight in water, which is why it's so popular as both a soil amendment and a hydroponic medium.

It's more environmentally friendly.

Since coco coir is repurposed waste from the production of coconut products, it has an environmental leg up on other options like peat moss and clay pellets. It also has a longer usable life than peat, since it's more durable and can be reused. Not only that, but it's a more easily renewed resource than peat or clay.

Bugs don't like it.

Pests aren't as much of a concern with coco coir compared to soil, making it an excellent added layer of protection in pest management. While coco coir isn't immune to pests, most growers experience far fewer bug problems when using it. Fungus gnats are the most common concern with coir and are generally fairly easy to deal with.

Cons of coco coir

While there are several benefits for adding coco coir to your grow, here are a few things to keep in mind.

It's an inert medium.

While coir looks and feels much like soil, it's a completely inert medium that offers no nutrients to your plants. As an amendment, it must be combined with potting mix and/or compost. As a hydroponic medium, all the nutrients will be provided via fertilizers when watering. Coco coir often needs calcium and magnesium and iron supplementation in hydroponic grows.

It can suffocate roots.

Its ability to retain water can be both a pro and a con. When used in excess, it can actually smother roots, which is why it is added to soil as an amendment or used along with perlite for hydroponic cultivation.

It takes a little extra work.

Using bricks of dehydrated coco coir takes some extra time and effort in setup since they need to be rehydrated and then mixed to your preference for soil or hydro-based growing. It also takes a little extra work to research suppliers and make sure they are properly aging and processing the coir to be safely used in your garden.

The bottom line

Coco coir is made from the protective husk of coconuts. Formerly a waste product of coconut production, only in recent decades did we realize that this tough and water-absorbent material is very useful in gardening and horticulture. It's an environmentally friendly choice that offers a lot of versatility for both soil and hydroponic cultivation. As such, it has become a staple in both home and commercial cannabis growers' toolkits.

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The information contained in this site is provided for informational purposes only, and should not be construed as medical or legal advice. This page was last updated on September 29, 2021.