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Written By Lara Wadsworth |
If you have gardened, had a house plant, or even been to a garden center in your life, chances are you have heard of peat moss. Peat moss is highly popular in the gardening world as an organic soil amendment and growing medium for seed starting, potting mixes, and microgreens. However, it has some significant drawbacks, especially from a sustainability standpoint. Peat bogs are a scarce resource that is in the process of being restored but with limited success. The alternative? Coconut coir! It is similar to peat moss in many essential ways but with a few key differences. Unlike peat, coco coir is harvested as a natural waste product of coconut farming. All of this and more I will discuss, so keep reading!
One of the biggest reasons that peat moss is so ideal for use in the garden is its water retention properties. Peat is a plant fiber naturally created in unique wetland bogs. It acts as a sponge to hold onto water and slowly release it as the plant needs it. It is often chosen as a soil amendment or as the base for soilless potting mixes because it can be sterilized and controlled much easier than soil. Peat is also fairly low in pH, meaning it is acidic compared to soil or other growing mediums; this can be an asset for altering the soil’s pH when used as an amendment, or it can be used to grow acidic-soil-loving plants.
Another big reason that peat moss is popular is that it is lightweight. Unlike soil, when peat is hydrated, it can be incredibly heavy to use or transport. Peat is light, even when wet. Therefore, it is ideal for large-scale use and transport for commercial sale and is often chosen for potted plants to make them easier to move around.
The biggest problem with peat is how it is harvested. Peat moss is a partially decomposed organic material derived from sphagnum moss and other plant matter that is found in waterlogged, acidic environments called peat bogs. It is harvested by draining the bogs, allowing the peat to dry, and then collecting it using specialized machinery. In order to have that convenient bag of peat moss ready to go in your local garden center, entire ecosystems are being destroyed. Peat bogs take thousands of years to form naturally, and therefore, as far as our human time scales are concerned, they are considered non-renewable resources. By harvesting this moss, we are destroying habitats, disrupting water flows, losing biodiversity, promoting erosion and soil degradation, wasting a valuable resource, and increasing the amount of carbon in the atmosphere. Healthy peat bogs are fantastic at sequestering carbon out of the atmosphere and into the earth, reducing greenhouse gasses and reducing the effects of climate change. Without these precious bogs, we will lose that tool.
Besides the environmental impact of peat moss, there are other reasons to ditch it. As mentioned before, the pH is quite low, meaning it is acidic. This can be beneficial in some scenarios, but if used too liberally, it can negatively impact the nutrient absorption of plants that typically favor a more neutral pH level. In addition, if not watered consistently, peat moss used in potting mixes can dry out too severely and cause problems with water absorption in plant roots. In this case, the mix needs to be completely replaced to save the plant, as dry peat loses its water-retentive properties and becomes hydrophobic. This often happens in houseplants. Therefore, it is not a one-and-done material but is rather ‘disposable’ and further contributes to its decline. Lastly, peat moss has zero nutritional value to plants. Any nutrients that a plant needs must be added to the peat. This means that additional fertilizers are still necessary for plants to grow.
Thankfully, not long ago, the horticultural community started catching on to the fact that peat moss isn’t as fantastic as we originally thought. The horticulture industry has been proactive in managing and restoring peat bogs sustainably. Partnerships with universities, best management practices, and environmental stewardship have been at the forefront of these efforts. The goal is to preserve as much of the peatlands as possible, minimize environmental impact, and reduce carbon emissions. The best way that you as an individual can help is by utilizing more sustainable alternatives. If there is no demand for the product, there will be less incentive to harvest and sell it. While there are certifications for responsibly produced peat, it is still not the best option regarding sustainability.
Let me introduce you to my friend coconut coir. Coco coir is derived from the shredded husks of coconuts and stands out as a sustainable and eco-friendly alternative to peat moss in gardening and horticulture uses. This readily available resource really can be the answer to all of our peat problems.
The biggest benefit of coco coir is that it behaves similarly to peat moss in a horticultural setting, yet it is incredibly sustainable. As a waste product from an already established industry, using coco coir reduces waste while preventing peat harvesting! Coconut coir is abundant and has a low carbon footprint.
Unlike peat, it has excellent water retention properties that do not diminish with time. This feature reduces the need for frequent watering, conserves water, and saves time and effort for gardeners.
Coconut coir is also suitable for organic gardening practices as it is produced and processed without pesticides. It is versatile in various gardening applications, similar to peat, yet it has a neutral pH; therefore, it needs to be amended less frequently than peat! Some of its most popular uses include amending garden soil to increase the organic matter contents, seed starting, potting plants, and growing microgreens.
Lastly, it is easy to compress coco coir and transport large amounts of it in a relatively small space. This makes it perfect for mail orders, emergency stashes, and people who don’t want to be lugging around huge bags of potting soil. Simply rehydrate by adding water and watch as it expands.
The disadvantages of coco coir are few yet worth mentioning. The biggest complaint I have heard concerning coconut coir is that it is said to have high salinity. This is because coconut trees are largely produced in coastal areas where salt is more likely to be present in the fibers. However, you don’t need to worry about this problem if you buy from a reputable company like True Leaf Market. In the processing of coco coir, it is washed many times, and the sodium is easily leached out.
Salinity is measured by using an EC value. The coco coir sold by TLM has tested with an EC of approximately 0.5, which is normal for healthy soil! A substance isn’t considered saline until the EC value is above 4.0.
The only other disadvantage of this medium that I’m aware of is that it also doesn’t naturally have many nutrients. This is part of what makes it great for growing microgreens while requiring added fertilizer for more mature grows. Amended forms of coco coir contain trace minerals and some potassium and phosphorus. Using an organic fertilizer with nitrogen to boost plant growth can be beneficial if you are using an all-coco-coir medium.
This past year was my first using coconut coir exclusively for my house plants, starting my garden seeds, and for microgreens growing. I must say, I was thoroughly impressed. It performed even better than some of the times I have used peat-based potting soil for these purposes. For my house plants and outdoor potted plants, I used the Minute Soil+ Max Water Retention Mix, and I will never go back! I went from needing to water my plants every few days to being able to go two weeks between waterings in some cases. Plus, it was easy to hydrate on my own and mix it up. I have had no problems with root rot or dryness. In fact, there are just a couple of plants I haven’t repotted with this mix yet, and I can seriously tell the difference. I need to water those growing in traditional potting mixes much more frequently.
I also loved using pure coco coir for seed starting. Its low nutrient profile is an advantage in this scenario, as there is no fertilizer to burn young seedlings. The coconut coir also changes color when it is wet or dry. It isn’t dramatic, but you get the hang of watching it. It is almost black when wet, but when dry, it is a lighter brown color. This made it easy to know when my seedlings needed to be watered. I had no problems with damping off! I used the 12-Cell Seed Starting Set, and this, combined with heating mats and grow lights, is my magic sauce for starting seeds inside!
For plants that need several weeks indoors, like tomatoes or peppers, we recommend mixing pure coco coir with perlite to provide adequate pore space for root growth.
While peat moss has long been a gardening staple for its water retention, lightweight nature, and adaptability, its environmental costs are undeniable. The destruction of peat bogs for harvesting disrupts ecosystems, accelerates climate change, and depletes a resource that takes millennia to regenerate. Fortunately, coconut coir offers a sustainable, versatile, and eco-friendly alternative that mirrors many of peat moss’s benefits while bypassing peat’s drawbacks. By switching to coir, gardeners can enhance their gardening practices and contribute to global efforts in environmental preservation. The small choice to opt for coco coir over peat moss can have a profound impact, aligning our gardening habits with a more sustainable future.
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Lara Wadsworth, True Leaf Market Writer |
I am a native of Southwestern Michigan, where I also reside, and I love all things plants! I got a Bachelor's Degree in Horticulture and found the first work-from-home job I could get. Now, I spend my days writing for TLM, playing with my dog, eating delicious food with my husband, and plotting my next landscape or gardening move. I believe everyone should get down and dirty in the soil now and then. Happy Gardening!
5 comments
i appreciate that you are voicing the very real problems with mining peat, which, when removed from peat bogs, releases far more CO2 into the atmosphere than deforestation does. My concerns with coir arise from the transportation of the product. True Leaf Market is located in the Southeast, which may not be distant from the origins of the product. My plant nursery is in Colorado, and for us, the environmental drawbacks of long-distance shipping of coir are similar to the drawbacks of peat. In addition, our water has a high pH, which, combined with the salinity of coir, makes the growing medium too alkaline. We are investigating newly introduced products that are made from shredded recycled paper. Will keep you posted on our trial results. Thank you!
This was a well written and informative article. Thank you!
I have tried starting plants in Coco Coir pots, then planting the potted seedling directly in the ground, assuming that the pot would eventually decompose and integrate into the soil. However, I have found that, a year or so later, the Coco Coir pot would still be in the ground, completely intact, with the seedling roots trapped inside. So I don’t use Coco Coir pots any longer.
What about salt content
Coco coir has a disadvantage that it has a high salinity and must be washed three times before use in gardening, hug! Too mush salt for the soil and plants.
Is there something that could be done for this? Your thoughts please.