Refinement of conventional and OMRI® fertilization of pot grown Solanum lycopersicum

P. Cockson, B.E. Whipker
A wealth of cultural and production information is available, however for organic production, quality information is often lacking or incomplete for pot grown culture. Therefore, this study sought to expand production guidelines and yield information in OMRI® produced tomatoes for magnesium and calcium fertility and compare these to values in a conventionally grown plants. Solanum lycopersicum ‘Ponchi™ F1’ and ‘Sweet and Sturdy™ F1’ (Prudac; Enkhuizen, NL) were grown as two groups in a greenhouse. The first group was grown with only OMRI® listed materials with nitrogen, phosphorus, and potassium held constant and varying rates of magnesium and calcium supplied (0, 7.35, 14.7, 29.4 ppm Mg and 0, 13.25, 26.5, 53.0 ppm Ca). The second group of tomatoes were grown conventionally using increasing rates of nitrogen with calcium and magnesium held constant (100, 200, 300 ppm N using 13N-2P2O5-13K2O-6Ca-3Mg fertilizer). Conventionally grown tomatoes had the largest biomass and the ‘Sweet and Sturdy’ also having the greatest biomass. ‘Sweet and Sturdy’ had no differences in green, red, and total fruit yields in the conventional group when compared to the organic group. However, the total plant dry weights were higher for the conventionally grown tomatoes when compared with the two highest rates of the OMRI® group. For the second harvest, red and green fruit dry weight between OMRI® and conventional was not significant but total fruit dry weights and total plant dry weight were higher in the conventional treatment when compared to some of the OMRI® treatments. The varied results seen between cultivars and among treatments shows that under certain treatments, both cultivars may be more successful when grown using OMRI® versus conventional fertility regimes. Both cultivars may perform well under an OMRI® fertility regime with the exception of the ‘Ponchi™ F1’ cultivar at the highest Mg and Ca fertility rates.
Cockson, P. and Whipker, B.E. (2021). Refinement of conventional and OMRI® fertilization of pot grown Solanum lycopersicum. Acta Hortic. 1305, 431-436
DOI: 10.17660/ActaHortic.2021.1305.56
tomato, OMRI®, calcium, magnesium, nutrition, fertility, organic

Acta Horticulturae