Reducing peat and growth regulator input in camellia pot cultivation

Abstract

Regulating plant development plays an important part in Camellia japonica L. pot production. Cultivation usually occurs on peat-based substrate and growth control is performed with triazoles application. However, there is an increasing need for suitable peat alternatives and more effective protocols. This study evaluated the effectiveness of three different dosages (50, 100, 200 mg/l) and two application protocols (foliar spray, once or twice) of paclobutrazol on two C. japonica cultivars grown on eight different substrate mixtures. The substrates were composed of four peat substitutes (local green compost, pumice, composted coconut peat, and pine bark) mixed with the standard substrate at 30-40% by volume. Treated plants showed reduction in most of the growth-related parameters, enhancement of ornamental value and an overall plant health improvement. Basically, one application of paclobutrazol 50 mg/l was sufficiently active. Among substrates, pine bark appeared to be a suitable partial peat alternative. Considering their lower cost and effective performances, pumice and coconut peat proved suitable alternatives, too.

Keywords

• flowering
• plant development
• paclobutrazol
• ornamental plants
• substrates