Development of growing substrates block for cut Dendrobium orchid production

Abstract

Development of new mixed growing substrates block for commercial cut-flower Dendrobium and the study of the substrates effect on Dendrobium cv. ‘Ear Sakul’ orchid’s growth was conducted to solve problem of shortage and rapid decomposition of traditional material as coconut husk. Agricultural wastes and by-products were mixed with cement base to produce the growing substrate in different ratios. The experimental design was randomized complete block design (RCBD) with 8 treatments and 10 blocks. Size and weight of growing substrates block are 23 x 33 x 8.6 cm, and 3.8 – 5.3 kg per piece, respectively. Comparative strength of the growing substrates block is 3,710 – 6,764 kg while the coconut husk is 1,786 kg, resulting in higher strengthening of the growing substrates than the coconut husk. In addition, all mixed substrate block has  higher water absorption ability than commercial cement block (29.1 – 54.1% and 8.4%) water absorption ability. After two years of cultivation, Ear Sakul cut flower which grown in the substrate T2 (cement 25% sand 15% and 60% rice husk chacoal) or T3. (cement 25% and 75% rice husk charcoal) or T4 (cement 25% sand 15% and 60% rice husk ash) were not different in plant growth in term of plant height (47.1 – 50.2 cm), number of pseudobulb (6.5 – 7.4 bulbs), number of front bulb’s leaves (6.1 – 6.8 leaves), and front bulb’s leaf area (239.6 – 303.9 cm²) when compared with control substrate inflorescence and flower quality was also indifferent among the treatments i.e. the number of inflorescences (7.5 – 8.4 inflorescence/clump), inflorescence length (43.9 – 45.7 cm) and vase life (19.6 – 20.6 days). It was concluded all mixed growing substrate block (T2, T3, and T4) have potential to use as new growing substrate for cut flower Dendrobium production in replacing of the coconut husk. They possess high strength, and simply transplanting method and long last properties in compared to the coconut husk