Influence of substrate pH on coleus growth

B.E. Whipker, D. Logan, P. Veazie, M.S. Ballance, K. Hicks, W.G. Owen
Three coleus (Coleus scutellarioides) cultivars (‘Big Blonde’, ‘Main Street Oxford Street’, and ‘Inferno’) were grown at six substrate pH levels to determine the effect of substrate pH on plant growth. Plants were grown for 7 weeks and measured for substrate pH and electrical conductivity, plant height, plant diameter, and shoot dry mass, along with calculating the growth index. The three cultivars varied in vigor, therefore to compare responses across all three cultivars, data was also analyzed on a percentage difference basis from their mean for each cultivar to determine overall trends. Substrates with lower levels than pH 4.7 or higher than pH 7.0 resulted in less plant growth. Optimal growth occurred between pH 5.3 and 6.3. This pH 5.3 to 6.3 range provides growers with an expanded pH range for growing coleus.
Whipker, B.E., Logan, D., Veazie, P., Ballance, M.S., Hicks, K. and Owen, W.G. (2024). Influence of substrate pH on coleus growth. Acta Hortic. 1389, 85-90
DOI: 10.17660/ActaHortic.2024.1389.9
nutrition, fertilizers, floriculture

Acta Horticulturae