Coco Coir: The Ultimate Guide

Coco coir is basically just a fancy name for coconut husk — the fibrous insides of a coconuts shell. It’s a sustainable, natural, and eco-friendly alternative to peat moss in pots. It’s compatible with all kinds of plants, and is super easy to use.

What Is Coco Coir?

It’s composed of partially decomposed coconut husks. It has an ideal pH of 6.0 to 6.5, and is available in two forms: fiber-rich or pithy fiber-less (pith is the hard part that you normally throw away). The smalgrains of coir are a great heat and light absorber, and are also excellent at holding water.

Why Is Coco Coir So Beneficial?

Coco coir is a great moisture, nutrient, and fertilizer-giver. The tiny fibers that make up the coir’s husk can bind nutrients like nitrates into the material. This means they’re optimal for soil pH, water holding capacity, and compostability. It’s also effective in warding off pests like fungus gnats and certain bacteria that cause root rot. At normal potting rates, it can help prevent root rot caused by overwatering as well as damping down opportunistic fungus larvae like white-fly maggots.

As far as we know it, coco coir in the context of gardening was introduced to the West in the 1,800s.

What Can I Use It For?

As a growing medium for plants. You can add it as a top dressing inside of pots, or use it as a soil additive with compost and other fertilizers for raised bed gardens that require minimal watering. This is a fantastic alternative to peat moss because coir is all-natural and sustainable whereas peat moss is not.

How Do I Use Coco Coir?

It’s easy! The first step is to figure out what form you’re buying. Then, simply follow the instructions on the package. For pithy coir, you need to mix it with compost and fertilizer before using it. With fiber-rich coir, you don’t need to do that. You can also use coir as a soil amendment alongside existing garden beds or in pots if you don’t want to create a whole new bed.

What Should I Know?

Coir is pH neutral (6), so it will not affect the acidity of your soil. However, if your soil is acidic (6.0 – 7.0) you should test the pH of your soil before you add any coir because it will increase it slightly. If your soil is neutral (7.1 – 7.5) or alkaline (above 7.5), then there’s no need to worry — it will not increase the pH of your soil even after months and months of use. Keep in mind, though, that the pH of your water will affect your garden’s pH just as much as coir itself.

Coco Coir Benefits and Uses

  • Make sure to wash it before use as it can carry coconuts residue from shipment.
  • Saves you money by not using peat moss.
  • Won’t harm or burn plants if used according to the package instructions.
  • Doesn’t require constant watering and can be left in the ground for up to three months (except fiber-less coir, which will deteriorate within a few weeks). I suppose that fiber-rich coir will last longer but there’s no guarantee in that department.
  • The only maintenance involved with coir-based potting mixes is watering. That’s it!

Coco Coir Concerns

If you use the fiber-rich version, you’ll need to stir it thoroughly before using it — especially if you’re using it in a raised bed. It tends to get clumpy when standing still, and I’ve noticed a lot of fibers tend to stick together.

It helps if you alternate stirring sessions with soaking some of the mixture in water for a few hours first. This will dissolve the fibers and make your mix much easier to work with once you’re ready to plant out into bigger pots or into your garden soil.

Coco Coir in Pots

Potting soil is made up of a combination of different components. In this case, the main component is coir. It’s the rest of the ingredients that vary from brand to brand.

For example, some brands of potting mix contain perlite while others contain vermiculite (fancy word for perlite with tiny dust-like specks of mica added to make it whiter).

Some brands also contain as many as three blends like Perlite + compost and Perlite + perlite + vermiculite. Sometimes they even mix those separately into different parts rather than just mixing them all together at once in one bag.

Types Of Coco Coir

  1. Coco pith – this type is made by removing the fiber from coconuts. It’s packed and sold in blocks that are compressed into bricks. It has a dark brown color, will expand a lot within water, and is lightweight.
  2. Coco fiber – also known as coco chips or coco peat, this type is made from the shredded coconut husk or shell rather than pith from inside the husk. It is lighter in color than coir pith (a creamy ivory) when it’s dry but will turn darker brown when wet. When dry it weighs a lot less than coir pith but expands just as much when soaked in water for an extended period of time.
  3. Coco chips – this type is made from coconut husk and is packed in small, irregularly shaped pieces. It is lightweight and will expand a lot.
  4. Coco bark – this type is made by dehydrating shredded coconut husk or coco fiber, then turning it into a powder for sale. This product weighs more than coco peat but is also lighter in color once dry (a creamy light green). When wetted, it expands less than coir pith or fiber but still expands a lot!
  5. Coir peat – this type of coir is created from the coconuts’ dried kernel (a porous piece of hard outer shell that surrounds the soft inner fruit).

Benefits of Coconut Coir

  1. Coconut coir has a very high cation exchange capacity, meaning it helps retain minerals in the soil.
  2. It does not contain any of the toxic materials found in some potting mixes such as fertilizers or pesticides.
  3. Coconut coir has a high content of organic matter and is therefore an excellent medium to use when growing plants like tomatoes or peppers that can’t tolerate saltier soils or those that like lots of nitrogen fertilizer like leafy greens and broccoli. It is used as a nutrient enhancer and it can retain up to 80% of its original weight after 3 months in the ground instead of the traditional 30%, making it much less expensive to buy and store for transplanting later!
  4. pH-neutral unlike some other substrates, coconut coir retains the soil’s natural balance of nutrients.
  5. Coconut coir is a great low-maintenance soil amendment for use in a culture planter or in planters such as our mobile raised bed garden boxes if you don’t have much time to devote and prefer to grow from seedlings when you can’t use pots.
  6. In addition, coconut coir can be used between trays of pots to enrich the top layers and improve drainage.
  7. Reusable: They are both durable and reusable due to their high resistance to cellulose degradation.

Drawbacks of using coco coir

  1. It is not suitable for plants that have a shallow root system or need to be transplanted often. These plants include tomatoes, peppers, cabbage and any leafy greens or crops of this type.
  2. It is not recommended for annuals (or vegetables) because it takes too long to amend after transplanting and the amount of salt may damage younger than 6 months old roots. The organic material can create anaerobic pockets in the soil which will prevent air circulation thus affecting root growth and plant growth in general.
  3. It is not recommended for acid-loving plants because cellulose damages their roots.
  4. The use of coco coir in a potting mix with peat and perlite can be a problem because it will take weeks if not months to fully break down compared to quarts and pumice pebbles which will become fully air porous after just a few days. Therefore, in order to make the potting mixture reach the correct density it would either need to be watered so much that it would kill the plants or would have to be watered less than usual (not enough) which may affect root growth.
  5. Potentially high salt content with their salted fish and meat, but the fact that a lot of water is used in salt curing certainly helps to reduce the final salt content of their foods. Note, too, that the amount of salt in the overall diet is also significantly reduced by a high intake of fresh fruit and vegetables.

How to get the best results from coco coir

There are three ways to use coco coir:

  1. As a soil amendment with other garden or potting mix ingredients;
  2. As a top dressing with other ingredients mixed in for top dressings and amendments;
  3. As a soil amendment within raised beds.

The first option is the easiest, but it will take longer for your coco coir to break down than pumice or peat used in a plain potting mix (or as an amendment inside raised beds).

The third option is the fastest because it uses air to break down the material and speeds up its breakdown by relying on aerobic and anaerobic bacteria on its own (the anaerobic bacteria breaks down the coco coir faster than aerobic bacteria).

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