Comparison of Coconut Coir, Rockwool, and Peat Cultivations for Tomato Production: Nutrient Balance, Plant Growth and Fruit Quality

Summary

This field trial evaluated coconut coir (CC) as a potential sustainable alternative to rockwool and peat-vermiculite substrates for protected tomato production. Coconut coir demonstrated advantages in potassium and sulphur uptake, photosynthetic rate, fruit weight and total yield compared to both conventional substrates, with lower overall nutrient loss (uncredited nutrient). However, blossom-end rot remained a physiological challenge under CC cultivation, suggesting that whilst CC shows promise as an environmentally preferable substrate, management strategies to prevent calcium-related fruit defects require further optimisation.

Regional applicability

Findings are relevant to United Kingdom protected horticulture and ornamental nursery sectors seeking to reduce reliance on peat and rockwool. Coconut coir adoption in UK commercial tomato production would require local validation under temperate glasshouse conditions and addressing of the reported blossom-end rot issue. The environmental benefit of coir (reduced peat extraction) aligns with UK sustainability policy, though coir sourcing and transport emissions merit consideration.

Key measures

EC and pH in root-zone solution and drainage; mineral ion concentrations; nutrient uptake (K, S, P); photosynthesis rate; individual fruit weight; total fruit yield; fruit organic acid content; blossom-end rot incidence across 13 fruit trusses

Outcomes reported

The study compared three growing substrates (coconut coir, rockwool, and peat-vermiculite) for tomato production, measuring effects on nutrient balance, plant growth, fruit yield and quality. Key outcomes included nutrient uptake patterns, photosynthesis rates, individual fruit weight, total yield, organic acid content, and incidence of blossom-end rot.

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