Container Geometry and Substrate Hydrophysical Properties Influence ‘Albion’ Strawberry Mother Plant Growth and Daughter Plant Production

Container geometry alters the distribution of air and water in soilless root zones, but its contribution to ‘Albion’ strawberry mother plant propagation has received limited study. Two greenhouse experiments evaluated four constructed polyvinyl chloride containers that differed in diameter, height, and volume: 15S2 (15.24-cm diameter × 11.0-cm height; 2.0 L), 15S3 (15.24 cm × 16.5 cm; 3.0 L), 10T2 (10.16 cm × 24.7 cm; 2.0 L), and 10T3 (10.16 cm × 37.0 cm; 3.0 L). Expt. 1 used a substrate containing 50% coarse perlite, 25% sphagnum peat, and 25% coconut coir (P50), whereas Expt. 2 compared P50 with 20% coarse perlite and 80% coconut coir (P20). Each container treatment in Expt. 1 and each container–substrate treatment combination in Expt. 2 had 10 single-plant replicates. Standardized substrate physical-property testing showed that P50 had 22.8% air space and 52.3% container capacity, whereas P20 had 10.4% air space and 78.9% container capacity. In Expt. 1, daughter plant number did not differ among containers (eight or nine per mother plant), although total plant dry mass differed. In Expt. 2, crown diameter, total plant dry mass, stolon-network dry mass, and daughter plant number differed among the eight container–substrate treatment combinations. Daughter plant number was greatest in 15S3-P20 (34) and 10T2-P50 (33), both of which exceeded 15S2-P20 (25); the remaining combinations were intermediate. The 15S2-P20 combination had the greatest mean crown diameter, whereas 10T3-P20 produced greater total and stolon-network dry mass than 15S2-P20. Responses therefore could not be attributed to container height, volume, or substrate air space alone. These results support managing container geometry and substrate hydrophysical properties as a coupled root zone system when designing greenhouse strawberry mother plant propagation systems.