Fern Research in Northern Thailand
Volume 2 Number 4 - December 1994
M.L Charuphant Thongtham
There has been considerable research at the Doi Pui Research Station, Chiang Mai and the University of Kasetsart on the use of ferns, both native and exotic, as a cash crop for the hill tribes of northern Thailand. The products are pot plants, cut-leaf ferns for fresh and dry flower arrangements and pickled young fern fronds. The latter have been exported to Japan. There are at least 30 species of ornamental fern that are suitable for pot plant production and out of these 18 species have been commercially propagated by spore culture. Fresh fonds of Davallia, Nephrolepis and Rumohra are in used in the cut-leaf fern trade. Apart from the bracken fern (Pteridium aquilinum var. wightianum) which is collected from the wild for food (it is the dominant fern covering almost one-third of the total highland area from an altitude of 3,800-5,400 feet above sea level) there are about 12 other species of fern used by the hill tribes for food and medicine.
For spore culture the best medium is sterilized clay-soil for terrestrial ferns and sterilized stag horn fern fibre for epiphytic ferns. In the highlands most ferns require 13-16 months to grow from spores to 3-4inch plants. For cut-leaf fern cultivation in the highlands a spacing of 40 cm. between rows and 20 cm. between plants in the row was recommended. Plant spacing of 10-30 cm. provided significantly longer marketable fronds than wider spacing. Shade level for growing ferns should be maintained at 50% shade for better quality of both cut and potted ferns. The most suitable growing media of ferns in the highlands was composed of forest topsoil and well-decayed leaf mould in the proportions 1:3.
Trials have also been conducted to find the best growing media for export and domestic consumption. A 1:1 ratio of rice husk and wood shavings was promising as a growing medium for export, while forest topsoil, coarse sand, leaf mould and cow manure at a 1:1:1:3:1 ratio was suitable for domestic use. Several trials are being made to evaluate the use of soiless media in potted fern culture for export and domestic use in the lowland. Several fertilizer trials were conducted in the highlands using ferns in plots and pots. It was found that 15-15-15 (N-P-K) at the rate of 5gm/8" pot/2 months or about 400Kg/rai/year is the most suitable for cut-leaved ferns in plots (1 ha. is approximately 12 rai). Slow release fertilizer (14-14-14) should be provided at a rate of 4gm/8" pot/3 months for ornamental pot ferns.
At present there are 29 species of ornamental fern being mass propagated by extensive spore culture at the Doi Pui Research. For transport the fresh fronds must be wrapped in wet newspaper and packed in cardboard boxes lined with a polythene sheet. The vase-life of the cut fern from the highlands is about one week.