Why Growers are Crazy for Coco Coir
By Kathleen Marshall 23 September 2020
Takeaway: Coco coir is an ideal grow medium because it holds water exceptionally well while still promoting good drainage and aeration. It is also easily renewable, unlike peat moss.
Coco coir, derived from the coconut hull, is made from the fibrous material between the outer husk and the actual coconut.
Originally, coir was used for making cordage and ropes in ancient India. It has also been used for making mats and other flooring materials.
In the 1980s, it was first used commercially in Holland to grow roses and lilies. Because coir worked so well to promote root growth, growers started using it for hydroponic gardening in place of peat moss.
Coco Coir has Amazing Water Holding Abilities
Coco coir is an ideal grow medium because it holds water exceptionally well while still promoting good drainage and aeration. It is also easily renewable, unlike peat moss, which has been the subject of controversy for some time now because it is considered a non-renewable resource.
An average coconut tree produces 150 coconuts a year, so there is a continual supply of a product that would otherwise be considered waste. Peat bogs, on the other hand, seem to be disappearing at a faster rate than they can be reasonable renewed. Some say that peat bogs take as long as 25 years to renew, while coco coir is constantly being made.
Coconut fiber provides good aeration for plants and also retains water well, which are just a couple reasons coco coir has become a favored grow medium.
The material also prevents nutrients from leaching.
Coco Coir has a Neutral pH Value
The pH of coir is also a huge benefit—while peat moss is considered acidic with a pH of 3.3 to 4, coir is closer to an ideal, neutral pH between 5.2 and 6.8. This means coco coir is ready to use for most plants without adding lime.
Nutritionally, coco is also an excellent choice. Depending on the source, it is rich in potassium, iron, manganese, copper and zinc. If you are growing hydroponically, this needs to be taken into consideration so you can provide the correct balance of nutrients.
Coir has a high cation exchange rate that allows it to store nutrients and release them as needed. On the flip side, coir tends to hold on to calcium and magnesium, so you may need to adjust your nutrient mix accordingly.
Coir promotes the growth of beneficial bacteria because of compounds called lignins. Not only will beneficial bacteria thrive when lignins are present, helping to minimize harmful bacteria, but if you add beneficial microbes to your hydroponic system, they will be optimized. This means better growth, higher yields and less disease.
Coco Coir is Packed with Nutrients
Coconuts are essentially giant seeds, and as such, the coir fibers are rich in hormones and bio-stimulants that encourage plant growth. In nature, this helps new coconut trees grow, but when used as a grow medium, other plants benefit from those natural growth enhancers as well.
Coir resists compaction and breaking down, so it can last as much as three times longer than peat moss. This should be considered when you look at the cost of coir versus peat moss. Coir is actually comparable in price, but because it lasts longer, it may be the more economical choice. Shop around, though, as prices vary.
How to Use Coco Coir as a Potting Medium
Coir resembles soil in its ready-to-use form and can be purchased in bags. It is also available in tightly packed, lightweight bricks, which is what you’ll often get if you order coir through the mail. The bricks are easily expanded—up to six times the original size—by adding water. Don’t worry about adding too much water.
When re-hydrating, as well as when watering plants, excess water just drains off. So, you won’t have a soggy grow medium, nor will you have to worry about overwatering your plants. Even when coir feels dry to the touch, it still retains plenty of water in its tube-like fibers so you won’t need to use as much water as you might when using other mediums.
Coco coir can be used as a potting medium and is an excellent medium to use for indoor plants, either on its own as a soilless grow medium, or mixed with other material, such as potting soil or perlite. Each pot should be filled loosely with coir, planted and watered well.
Repotting is just as simple. Wet the coir thoroughly, turn the pot upside down and tap firmly while supporting the plant until it slides out of the pot. Add some additional coir to the new pot and place the plant into its new container. Fill the new pot with more coir and water well.
How to Use Coco Coir in Hydroponics Systems
To use coir in a hydroponic system, you will need to make a few changes to how you would normally do things. First, choose coir that is specifically for hydroponics, not the kind sold as decorative mulch.
Second, be sure to rinse the coir well because it is naturally high in salts, and while high-quality coir should be already rinsed, it is always better to be safe than sorry. Rinse until the water running off is clear. After rinsing, you will find that coir tends to clump. Just break it apart with your hands so it is loose before planting.
And finally, you might need to use a nutrient mix that is specific for coir growing. This is because of coir’s ability to hold and release certain nutrients, as mentioned earlier. Even if you have the perfect nutrient balance in the reservoir, you may still see signs of deficiencies if you don’t take account for how coir provides those nutrients to your plants. Many of the companies that sell coir products also offer coir-specific nutrients.
Recycling Used Coco Coir
When you are ready to recycle your used coir after many uses, it can be mixed into your garden soil outdoors. Because it is so fibrous, it is excellent for breaking up clay soil and improving the ability of sandy soil to hold water and nutrients. You can even use it as a mulch to inhibit weeds and keep the soil moist. There is never any need to throw away coir—its value for growers seems endless.