How to Use Coconut Coir in Your Garden
An Ideal Seed Starter Plus Other Indoor and Outdoor Uses With Plants
The Spruce / Phoebe Cheong
Fact checked by Jillian DaraReviewed by Julie Thompson-Adolf
Coconut coir (pronounced COY-er) is a byproduct that comes from coconuts and has a variety of purposes. The fibrous husks of the coconut's inner shell are processed and used for products including rugs, ropes, brushes, and even upholstery stuffing. You're probably familiar with coir doormats and coir hanging basket liners. Coconut coir is rot-resistant, which also makes it perfect for outdoor use in the garden. Learn how coconut coir is also becoming increasingly popular as a potting mix and organic soil amendment, and how you can use it to benefit your garden.
How Coconut Coir Is Used in Gardening
Besides the use of coconut coir as a liner for hanging baskets, the material is commonly used as an ingredient of potting mixes for starting seeds. It is also used for garden beds and container plants, as well as a soilless mix for hydroponics and climbing plants.
Coconut coir is also used as a soil amendment for any type of soil. It improves the air porosity of soils, even when wet, and aids in moisture retention. Coconut coir absorbs 30 percent more water than peat and is much easier to re-wet when dry. It helps loosen the texture of clay soil and improve drainage. It also allows sandy soil to hold onto water longer.
What Is Air Porosity?
In gardening, porosity refers to your soil's permeability to both air and water. Depending on how big the pores are, a soil's pockets for permeability are called macropores or micropores. Plants need both air and water to survive and grow, so it's important to make sure your soil's porosity is appropriate for your plant.
Advantages of Using Coir Over Peat
Peat takes hundreds of years to form. Although many reputable firms in the peat industry are trying to harvest and manage peat at a responsible, sustainable rate, the demand is so high that alternative substances are needed. Coconuts grow throughout the year and can be harvested every two months, which makes them sustainable. Here are the advantages of using coir instead of peat:
Coir is slower to decompose than peat, so it lasts longer in the soil.
It is sterile and free of weed seeds.
It has a less acidic soil pH, generally in the 5.8 to 6.8 range. (Peat is in the 3.5 to 4.5 range.)
Coir improves air porosity in soils, even when wet, as well as improving moisture retention.
Since the coir's pH is already neutral, you do not need to add lime to sweeten the soil.
It is easier to re-wet when it dries out which helps plants recover from dry conditions quicker. As a result, water is saved because there are less irrigation requirements.
Disadvantages of Using Coir
Coconut coir does have some downsides as a gardening material. Here are the disadvantages:
Coir is compacted and requires proper processing to loosen it for use in the garden.
Because it retains water, there is a chance of salt buildup in the soil.
Like peat, coir has negligible amounts of calcium but since it has a neutral pH you still do not need to add lime to the soil.
Coir doesn't have much in the way of other nutrients, either. However, it is fairly rich in potassium and a handful of other micronutrients.
Coir is more expensive and sometimes harder to find than peat.
Types of Coconut Coir Products
Coconut coir goes by many names. You may find it labeled as coir-peat, coco-peat, coir fiber pith, coir dust, and other similar-sounding brand names. Dark brown coir is from mature coconuts. White coir, which is finer and softer, is made from immature green coconuts. Here are the forms in which you'll find coconut coir for use in your garden.
Bricks and Blocks
Horticultural coir is a peat-like substance that is commonly sold in machine-compressed bricks or blocks. It is not always easy to find brick or blocks of coir. When you do find it, do not use it right away out of the packaging. The blocks need to be properly soaked before use.
You will need to soak the coir brick to turn it into a loamy texture. An 11-pound brick (about 12.5 x 12.5 x 8 inches) will make approximately 16 gallons of coir. Take these simple steps to reconstitute your brick of coir:
Find a large container: Place the coir brick in a large container. The brick will increase about six times in volume; make sure your container is large enough to hold it.
Add water per the label's instructions: The instructions for an 11-pound brick typically suggest using 5 quarts of water but you may need more.
Help it reconstitute: After about 15 minutes the outer portion of the brick will have softened. Help speed the process by breaking and crumbling the softened sections and allowing the water to reach further into the center. Don't worry if it seems like all you have is a muddy mess. Once the entire brick is exposed, it will absorb the water.
Ready for use: When the whole brick has crumbled, the coir is ready to use. It will remain loose, even when dry, and will last for years.
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Chips
Coconut husks are chopped into coconut coir chips which are sold in bags and used to aerate soil. The chips are much coarser than finer coconut coir which is also used to amend soil. Chips are ideal for hydroponic plants since they offer plenty of aeration in addition to water retention.
Potting Soil
Coir is used in some indoor potting mixes, as well. Most potting mixes still contain peat, which is a non-renewable resource. However, you can mix up your potting mix blend quite easily using coconut coir. Since coir is organic and sterile, it's an excellent choice for starting seeds. If you are using it as a seed starter, it is often recommended the mix contain no more than 40 percent coir.
Baskets
Preformed coconut coir basket liners help to retain moisture in hanging plants that quickly dry out. Liners come in bowl or rectangular shapes to fit containers. Liners last about one to two years before they become ratty, depending on where you hang the basket (inside or outside), weather conditions, and how much you water your plant. Keep an eye out for deterioration and recycle them into your garden soil.
Pots
When buying potted plants at a garden center, look for pots made from coconut coir. Since it is a compostable material, coir is a good choice when planning a sustainable garden. You can simply place the pot directly into the ground when transplanting a plant, which further reduces its stress.
Coco Poles
Coco poles, also called coconut coir poles, are used as support to help climbing plants attain their height. Plants that benefit from coco poles include monsteras, philodendrons, and pothos. Coco poles are viable alternatives to sphagnum moss poles, also used for the same purpose. However, coco poles may not retain as much water as a moss pole.
Read Next: The Best Potting Soils For Indoor Plant Enthusiasts
Read the original article on The Spruce.
