Flower Yield and Quality of Two Rose Cultivars Grown in Phenolic Foam LC Slab and Phenolic Foam RC Slab in Comparison to Perlite and Rockwool Slab

Abstract

Two standard cut rose (Rosa hybrida) 'Rock Fire' and 'Feel Lip' were propagated by single nodal cuttings. Each cutting with a five-leaflet leaf was stuck in a rockwool cube (Delta, 5 cm x 5 cm x 5 cm, (Grodan Co., Ltd., Denmark) on May 16, 2011. After 32 days, rooted uniform saplings were transplanted onto the four different growing media, perlite (Pergreen, No. 1, G-Biotech Co., Ltd., Korea), rockwool slab (Delta, 100 cm x 20 cm x 7.5 cm, Grodan Co. Ltd., Denmark), phenolic foam LC slab (100 cm x 20 cm x 7.5 cm, Smithers Oasis Co., Ltd., Korea), or phenolic foam RC slab (100 cm x 20 cm x 7.5 cm, Smithers Oasis Co., Ltd., Korea), laid out in a completely randomized design on a bench in a commercial grower's plastic house. The nutrient solution was supplied uniformly through a drip irrigation system. The irrigation frequency was dependent on amount of solar radiation. Yield and quality of harvested flower stems were measured for five successive harvests during a period of 11 months. Growth parameters measured were stem length, stem diameter, number of five-leaflet leaves per stem, stem fresh weight, number of harvested cut flowers per ten plants by grade, total yield, and tissue contents of inorganic elements. Measured growth parameters, such as stem length, number and quality of harvested stems, and contents of inorganic elements, were similar in all the tested growing media, except perlite in which these values were the lowest. The results obtained suggests that the widely used rockwool slab can be replaced with the new phenolic medium such as phenolic foam LC slab for commercial scale hydroponic productions of cut roses.