Cocopeat (coconut coir) is compressed coconut husk fibre — a renewable by-product of an industry our region has in abundance. Used correctly it is the best seedling and container medium available in Mauritius. Used incorrectly it grows sad yellow plants, and the reasons why are worth two minutes of your time.
What Cocopeat Is — and Is Not
- It IS an outstanding physical medium: it holds 8–10 times its weight in water while staying airy, and it re-wets easily after drying out (unlike peat or dried-out soil).
- It is NOT a fertiliser. Cocopeat contains almost no nutrients. Every plant grown in it must be fed — that is a feature (you control the feeding), not a flaw.
Hydrating a Block
- Place the 5kg block in a large tub or wheelbarrow.
- Add 20–25 litres of water gradually and let it drink for 30–60 minutes.
- Break it apart as it swells — you will end up with roughly 60–70 litres of fluffy medium.
- Squeeze test: a handful should feel like a wrung-out sponge, moist but not dripping.
The Rinse Question
Coir is washed during processing, but some batches retain natural salts (mainly potassium and sodium). If your cocopeat is unbuffered or you are unsure, rinse the hydrated coir once or twice with fresh water and drain. Seedlings are the most salt-sensitive stage — a rinse is cheap insurance.
The Mixes That Work
For seedling trays:
- 60% cocopeat + 40% fine sifted compost. Light, moist, and feeds the seedling for its first weeks.
For containers and pots:
- 40% cocopeat + 40% compost + 20% garden soil or coarse sand. Holds moisture through a coastal summer without waterlogging in a plateau winter.
For improving garden beds:
- Work a few litres per square metre into sandy or fast-drying soil — it behaves like a permanent moisture reservoir around the roots.
Watering and Feeding in Cocopeat
- Cocopeat's surface dries pale while staying moist beneath — judge by weight or finger, not colour.
- Because it holds no nutrients, feed container plants fortnightly with liquid organic fertiliser or top-dress with compost monthly.
- In the dry west of the island, cocopeat in the mix visibly reduces watering frequency — that is the main reason to use it.
Reuse
Old cocopeat from finished seedlings does not go to waste: refresh it with compost and reuse it for a season or two, then dig it into a garden bed as organic matter. Nothing leaves the system — the same circular logic as the rest of organic growing.
Cocopeat mixes for seedlings and containers are covered in Module 2 of the Grower Academy.