Coco Coir as a Hydroponic Growing Media
Introduction
Coco coir is a soilless growing medium made from the fibrous husks of coconut shells. It offers excellent water retention, good aeration, and a near-neutral pH, making it a sustainable alternative to peat moss in hydroponic systems [1][2].
Making It Yourself (DIY)
- Source husks: Collect coconut husks and rinse to remove debris.
- Fiber separation: Soak husks in water for 24–48 h, then beat to loosen fibers.
- Washing: Rinse repeatedly until runoff EC is below 0.5 mS/cm.
- Buffering: Soak in a calcium-magnesium solution (2 g Ca & 0.5 g Mg per 100 g coir) for 12 h to prevent potassium lockout.
- Drying & storage: Spread fibers to air-dry, then compress into bricks or bags.
Specifications
| Specification |
Value |
| Water Retention |
Holds up to 10× its weight in water [1] |
| Aeration |
Good air porosity (~10–20 %) [2][4] |
| pH Neutrality |
Natural pH 5.5–6.8; ideal for most crops [1] |
| Reusability |
Reusable for 2–3 crop cycles with proper flushing [3] |
Plant Suitability
| Cultivar |
Suitability |
Notes |
| Lettuce (e.g. Buttercrunch) |
Excellent |
Consistent moisture favors leafy growth |
| Tomato (e.g. Moneymaker) |
Very Good |
Strong aeration prevents root diseases |
| Basil (e.g. Genovese) |
Excellent |
Fine roots thrive in loose fibers |
| Strawberry (e.g. Albion) |
Good |
May require pH monitoring for fruit quality |
| Peppers (e.g. California Wonder) |
Very Good |
High moisture retention aids fruit set |
Hydroponic System Suitability
| System |
Suitability |
Notes |
| Nutrient Film Technique (NFT) |
Good |
Works in small cubes at channel inlets |
| Deep Water Culture (DWC) |
Excellent |
Roots suspend freely; coir blocks support plants |
| Ebb & Flow |
Excellent |
Flood-and-drain cycles keep moisture balanced |
| Drip Irrigation |
Excellent |
Drips maintain even moisture without compaction |
| Aeroponics |
Moderate |
May hold too much water for fine mist systems |
Risks of Pests, Diseases, and Other Problems
- Salt buildup: Requires periodic flushing to avoid nutrient lockout [5].
- Nitrogen drawdown: Poorly buffered coir can tie up nitrogen early on [5].
- Pythium (root rot): Good aeration helps prevent it but stagnant zones can harbor pathogens [4].
- Algae growth: Cover exposed coir surfaces to block light.
Advantages and Disadvantages
- Advantages:
- Renewable byproduct of coconut industry
- Excellent water retention and aeration balance
- Near-neutral pH reduces adjustment needs
- Reusable for multiple cycles
- Disadvantages:
- Requires thorough buffering and washing
- Potential for salt and nutrient imbalances
- Bulk and shipping costs if not locally sourced
- Biodegrades over time; limited lifespan
Citations
- [1] Why is COCO Coir Perfect for Hydroponics and Aquaponics - https://www.plantbest.com/us/bloglist/why-is-coco-coir-perfect-for-hydroponics-and-aquaponics
- [2] Your Guide to Choosing a Hydroponic Substrate - https://re-nuble.com/blogs/re-nuble/your-guide-to-choosing-a-hydroponic-substrate
- [3] 5 Best Hydroponic Growing Media for Water Retention - https://www.greengenius.com.au/blogs/news/5-best-hydroponic-growing-media-for-water-retention
- [4] Soilless Growing Mediums – Oklahoma State University Extension - https://extension.okstate.edu/fact-sheets/soilless-growing-mediums.html
- [5] Coir – Wikipedia - https://en.wikipedia.org/wiki/Coir