Value of Volcanic Ash as an Additive for Cocopeat Growing
Volcanic ash has notable potential as an additive to cocopeat in horticultural and agricultural
applications. Below is an evaluation based on available research and practical findings.
Volcanic ash is rich in a variety of minerals, including silicon, iron, magnesium, calcium,
potassium, and trace elements, which are often present in much higher concentrations
compared to organic substrates like cocopeat.
When used as a soil amendment, volcanic ash can improve soil fertility, supply essential
nutrients, and enhance plant growth and yield. For example, studies have shown that
volcanic ash can increase calcium levels, which encourages tuber growth in potatoes2.
In regions such as around Mount Etna, volcanic ash has been credited with making soils
exceptionally fertile, supporting robust crop growth and reducing the need for chemical
fertilizers.
Physical Properties and Water Management
- Volcanic ash improves soil structure, making it more aerated and better drained, which is beneficial when mixed with cocopeat—a substrate already valued for its water retention and aeration 3
- The unique ability of volcanic ash to retain water can help reduce drought risks and ensure more consistent moisture availability for crops.
Plant Health and Disease Resistance
- The mineral content of volcanic ash, particularly silicon and magnesium, has been linked to improved chlorophyll production and overall plant health. In soilless cultivation, substrates with volcanic materials have maintained higher chlorophyll content and sustained plant vitality better than cocopeat alone.
- Plants grown with volcanic ash often exhibit greater robustness and resistance to disease, likely due to the natural supply of protective minerals
Sustainability and Environmental Impact
- Using volcanic ash as a natural fertilizer or soil conditioner reduces reliance on chemical fertilizers, making it a more sustainable and eco-friendly option for growers.
- Volcanic ash is stable and resistant to degradation, meaning it can last for many years in substrate mixes, unlike some organic materials that break down more quickly
Practical Applications with Cocopeat
- Volcanic ash can be mixed directly with cocopeat to create a substrate that combines the excellent water retention and aeration of cocopeat with the mineral richness of volcanic ash.
- Studies on biofilters show that combining cocopeat and ash (in various ratios) can be effective for adsorption and filtration, indicating good compatibility and functional synergy between the two materials
- Potential Limitations
- While volcanic ash increases some nutrient levels (e.g., calcium), studies have shown that the overall nutrient content in plant tissues may not always be higher than with pure cocopeat or control treatments2. However, the levels remain within the acceptable range for healthy growth.
- The pH of volcanic ash is slightly acidic to neutral (around 5.9), which generally complements cocopeat’s pH, but growers should monitor substrate pH to avoid imbalances.
Summary Table: Volcanic Ash vs. Cocopeat as Substrate Additives
| Property | Cocopeat | Volcanic Ash | Combined Use (Mix) |
|---|---|---|---|
| Water Retention | High | Moderate to High | High |
| Aeration | Good | Improves further | Excellent |
| Nutrient Content | Low (mainly K) | High (multimineral) | Balanced, enriched |
| Disease Resistance | Moderate | Enhanced | Enhanced |
| Longevity/Stability | Degrades over time | Very stable | Improved |
| Sustainability | Renewable | Natural, abundant | Highly sustainable |
Conclusion
Adding volcanic ash to cocopeat substrates offers multiple agronomic benefits:
- Enhanced mineral nutrition
- Improved substrate structure and water management
- Greater plant health and resilience
- Increased sustainability and reduced environmental impact
The combination is particularly valuable for soilless cultivation and sustainable agriculture, making volcanic ash a promising additive for cocopeat growing systems