The physical properties of rooting media for the establishment of plugs in a greenhouse are
modified according to variations in the greenhouse environment throughout the season. In this
study, we established a standard for rooting media for the production of plug seedlings for each
growing season (summer, winter and spring∙fall). Eight types of peatmoss (PM) and 4 types of
perlite (PL) commonly used in Korea were collected and blended with the ratio of 7 parts PM to 3
parts PL (v/v) to make 32 different rooting media blends. We determined the total porosity (TP),
container capacity (CC), air-filled porosity (AFP), pH, and electrical conductivity (EC) of the 32
media blends, and 6 media blends were selected for seasonal use. We also conducted additional
analyses for plant easily available water (EAW), buffering water (BW), cation exchange capacity
(CEC), and nutrient contents in the 6 media blends. The TP, CC, and AFP of the 32 media blends
ranged from 64.7 to 96.0%, 42.9 to 90.1%, and 1.3 to 27.8%, respectively, indicating that the
physical properties were strongly influenced by the type of PM and PL. The pH and EC of the
PMs ranged from 2.96 to 3.81 and 0.08 to 0.47 dS∙m-1, respectively. However, after blending the
PM with the PL the pH was raised and the EC was lowered The media blends selected for the
summer growing season were Blonde Golden peatmoss (BG) + No. 1 perlite size < 1 mm (PE1)
and Latagro 0-10 mm (L1) + No. 2 perlite size 1-2 mm (PE2). These two media blends had 89.8-
90.9% of TP, 80.8-81.3% of CC, and 9.0-9.7% of AFP. The media blends selected for the winter
growing season were Sfagnumi Turvas (ST) + PE2 and Latagro 20-40 mm (L3) + PE2. These
media blends had 79.9-86.7% of TP, 60.4-74.9% of CC, and 11.8-19.6% of AFP. The TP, CC, and
AFP of two media blends, BG + No.3 perlite 2-5 mm (PE3) and Orange peatmoss (O) + PE3,
selected for the spring and fall growing seasons, respectively, were 85.2-87.3%, 77.9%, and 7.4-
9.4%, respectively. The percentage of EAW of the media blends selected for the spring, summer,
and winter growing seasons ranged from 24.2-24.9%, 22.0-28.6%, and 18.0-21.8%, respectively, but the percentages of BW were not significantly different among the selected root media blends. The pH, EC, and
CEC of the 6 selected media blends ranged from 3.11-3.97, 0.06-0.26 dS∙m-1, and 97-119 meq·100g-1, respectively.
Horticultural Science and Technology
