Capillary Irrigation for Container Nurseries: a practical alternative to overhead irrigation?

We compared overhead irrigation, irrigation using third-generation prefabricated capillary mats, and combined systems for plants in two container sizes: multi-cell trays and trade gallons. For each combination, we monitored applied water, fertilizer, magnesium and acid, plant losses, time spent on issues related to irrigation, and staff satisfaction. We also determined the costs of installing the capillary mats in new growing areas and adding capillary mats to growing areas with existing overhead irrigation. For the small plants in multi-cell trays, capillary mats plus overhead irrigation (essential during extreme weather and for initial watering-in) reduced applied water by 63% over overhead irrigation alone. This resulted in a $33.07 savings in fertigation costs per thousand plants per year. The cost to add capillary mats to existing growing beds with overhead irrigation was $27.55 per 1000 plants. For plants in trade gallons, capillary mat irrigation alone worked very well, reduced applied water by 70%, and resulted in much more pleasant working conditions. As the result of this study, we will be retrofitting our growing areas with third-generation prefabricated capillary mats.