Coconut Coir Pros And Cons - Benefits And Drawbacks Of Planting In Coir

Cocunut husks
(Image credit: born1993 / Getty Images)

Love coconut and love our planet? Coconut coir may be the right growing media for you, as it is just the cast off clothing from a harvested coconut. Using this rather than discarding it is a win-win for environmental responsibility, and is becoming popular due to its use as a natural planting medium. You can plant directly in coir or mix it with other beneficial amendments.

While this is a great growing medium for many plants with a number of benefits, it's just as important to consider the possible cons of coconut coir as well. Bonnie and Becca will go over the most common coconut coir pros and cons here.

Reasons to Plant in Coconut Coir

(Bonnie's viewpoint) Most of us have had the mantra, "reduce, reuse, recycle" drilled into our brains over the last few decades. While it may seem a bit trite, the core message is one that could save our planet. Coconut coir is just the husk of the nut that has been soaked in water for up to 6 weeks and then spun into a fiber-like product. The fibers are extremely strong and can be stretched or compressed without damaging them. The coir is dried and pressed into pots, discs or just left loose and bagged up as a mulch. They're also commonly made into hanging basket liners.

  • Sustainability - I feel there are a number of reasons to plant in coconut coir, and one of the main reasons is its sustainability. You can reuse coconut coir, unlike many other planting mediums, such as peat moss. And, unlike peat moss, which is harvested from gradually declining bogs, coir is the result of a repurposed waste - the coconut husk. The average mature coconut palm can produce up to 150 nuts per year. Harvested and cleaned coconuts end up in our supermarkets, but all that shaggy coir was traditionally discarded or burned, increasing our carbon problems. With modern methods, the stuff is produced with minimal energy, and is lightweight to ship.
  • Increases aeration and retains water - Coir is well known for its ability to provide good aeration, which is great for plants. Coconut coir pros also tout its ability to soak up 10x its weight in water. When coir is used in hydroponic systems with nutrient solution, the roots uptake those nutrients more quickly than in soil mixes. Used as a planting medium, your plants will require much less watering.
  • Ease of use and few issues - Among the benefits of coir is its pH neutrality. Coconut coir pros usually recommend mixing the product with other plant amendments, but you can use it straight too. It also has anti-fungal properties and many pests avoid living in the stuff, minimizing insect and disease problems.
  • It doesn't cost much - Coir is also relatively inexpensive, especially if you get it in compressed forms. All you need to do is soak it and it will expand to nearly double the size. This makes for a lightweight, easy-to-transport plant substrate.
  • Different types to choose from - There are different forms of coconut coir. Coco pith (sometimes called coconut peat) is so absorbent that it could keep plant roots overly wet and should probably be mixed. Coco fibers allow for superior aeration and let oxygen into plant roots easily. Coco chips are excellent when mixed into soil, as they create air pockets while also retaining some water.

Disadvantages of Coconut Coir Planting

(Becca's viewpoint) I certainly agree there are advantages to planting in this medium, but let me mention there are disadvantages of coconut coir too.

  • Hard to find - First, it can be hard to find, at least locally. I found one bag at a Walmart and that was two or three years ago. After an extensive search, I had to order it. And the coir I ordered was in a block, hard to break down and then difficult to get wet.
  • Problems from salt - Some gardeners have experienced cons of coconut coir because of too much salt in the product. The electrical conductivity of water in growing medium that is too salty can prevent or deter the uptake of water by plant roots. It can also cause issues with the absorption of nutrients. This often happens because those harvesting the coir rinse the product in saltwater as opposed to fresh water. Know the distributor of the material before you purchase and, if the price seems too good to be true, check the fine print and call the company, if needed. Salt in the product has the potential to cause major problems.
  • Doesn't contain nutrients - Other drawbacks of planting in coir include nutrient addition, as this is an inert (no nutrients) medium. I prefer doing my own fertilization, but I know many of you expect nutrients to be in your potting medium. You can mix coir with another soil mixture at half and half to get some of the nutrients, but you likely still need to add fertilizer. Also, coir has the inclination to hold back calcium, magnesium and iron. While it stores and releases most added nutrients readily, because of a high cation exchange, you will possibly need to find a formula that has extras of those mentioned. I primarily use coir for growing succulents that need only limited nutrients, so it is not a problem, but may be for some other plants.

Using a product that would have otherwise been discarded or burned is an environmentally conscious decision. While it won't fit every plant's needs, it is a versatile and adaptable soil amendment that can take the place of endangered peat. Just make sure you consider all of its possible downsides too prior to use.

Bonnie Grant