Coco coir is an incredibly versatile peat free growing medium that many gardeners swear by for their indoor and outdoor gardens. Whether it’s tomatoes, microgreens, flowers or using it as a mulch - there are countless uses for this unique and sustainable growing medium.
However there are a few things you need to know about coco coir, such as managing nutrients and selecting responsibly produced coir, if you are going to use it to its full potential. In this article we will cover:
- What is coir and how is it produced
- The advantages and disadvantages of coir
- How to use coir for microgreens and vegetables
What is coir and how is it produced
Coco coir is a natural fibre derived from the shredded husks of coconuts. This tough fibre is used widely for everything from doormats, ropes and brushes to upholstery padding and of course countless applications in the garden. The fibrous husks are stripped from the shell, shredded, washed, dried in the sun and screened into varying grades. The coir is then compressed into blocks with hydraulic presses, ready for use.
However not all coir is created equal. Many producers sterilise their coir with methyl bromide, a powerful and toxic chemical used as a pesticide. It is highly damaging to the environment and has no place in the garden or in our food. That’s why we take extra care to source 100% certified organic coco coir and are one of the few companies in Europe to do so.
The advantages and disadvantages of coir
Coco coir decomposes relatively slowly meaning it can benefit soil for a long time. It is composed of strong cellulose fiber with a high lignin content meaning it has a very high water holding capacity. Coir can help improve the texture of sandy soil by adding beneficial properties such as good aeration and water retention. For clay heavy soils, coir can be used to aid drainage and aeration. Slow decomposition and limited compaction results in a very stable, fluffy and open structure that air can penetrate which in turn promotes larger, healthier roots.
Coir can also be used as a very effective mulch, keeping water in the soil where your plants need it and seeing them through any tough dry spells.
Coir is naturally inert, meaning it has zero nutritional value to your plants. While this can be seen as a disadvantage, it means that for plants with specific nutrient requirements you can add the exact levels of the essential nutrients your plants need. When mixed with a rich compost or worm castings, coco coir also becomes a versatile potting mix. You can vary the nutrient levels to suit whatever you happen to be growing. Coco coir is the key component of many peat free composts on the market currently.
Coir also boasts natural anti fungal properties and may help resist soil borne diseases such as Pythium and Phytophthora. Because the top layer of coir dries out very quickly, this can help deter certain moisture loving pests.
A disadvantage of some coir products is that they can have a very high salt content due to being washed with salt water during the processing stages. This is more common with lower quality inorganic coir products and can be avoided by buying from reputable sources. (Such as ourselves!)
How to use coir for microgreens and vegetables
As mentioned above, coco coir is inert and therefore will not sustain a large plant without the addition of nutrients. Microgreens however can sustain themselves from the starches stored in the seed and can grow without any additional amendments for up to 2 weeks. That said, we like to add about 20% peat free compost or worm castings to our coir along with some perlite, which will create the absolute optimal conditions for strong, healthy and large crops of microgreens.
For plants and veggies, the addition of nutrients is a must. There are many coir specific fertilisers on the market that, unlike fertilisers that feed the soil microbes which in turn feed your plants, contain minerals and nutrients in a form that are directly available to your plants. For growing vegetables in coir, a 50/50 mix of coir to compost with the addition of some perlite will give you a fluffy and breathable potting mix that your plants will simply adore!
We hope this guide has been useful in learning about coco coir. We stock coir blocks from as little as one Litre, which will fill our standard microgreen trays, all the way up to 70 litre bales for larger projects.
Get in touch with us any time to discuss your needs and we can work out a plan that works for you.