Perilla 485
seeds are kept at room temperature for about a week before sowing. Seeds are often
soaked in gibberellic acid solution (50 ppm) for breaking dormancy. Seeds germinate
in 6–10 days, and the optimum temperature is 22 ∞C (Tanaka et al., 1997). Seedbeds
1.2–1.5 m wide and of convenient length are used for seed sowing. Pre-soaking is
essential for good germination. Seeds are then suspended in water and spread evenly
on the bed at the rate of 9–10 ml per m^2. Bed is then covered with sand and pressed down
using a board. The beds are covered with polythene sheeting to retain high humidity.
When Perilla is grown for green bud, harvesting is done when the cotyledons are
expanded fully and the first pair of true leaves has grown out; which takes about ten
days in summer and 15–20 days in other seasons. The purple variety (purple bud) is
harvested when two pairs of leaves have grown out. When Perilla is grown for heads
(head perilla) seedlings are transplanted in field and a basal dressing of 1.5 kg
nitrogen, 2 kg phosphorous and 2 kg potash are given per 100 m^2 area. The inflorescences
(heads) are harvested when five or six flowers open. The protocol for Perilla cultivation
is given in Table 29.1.
29.2.2 Cultivation in Korea
In Korea, Perilla is also an important oil seed crop, and the annual production is
around 36,800 tons. Perilla leaves are a by-product and consumed in a salted form or
wrapped form with meat and fish (Tanaka et al., 1997). The important cultivars for
seed production are Sciwon No. 8, Sciwon No. 10 and Guppo; many local genotypes
are also in use. Seeds are sown in open fields in April–June. Leaves are harvested
from mid-June to September. Winter cultivation is from October (sowing) to March
(harvesting). In winter, additional illumination is required for proper growth. Seed
rate is 3 kg/ha, and the plant density is around 250,000/ha. Fertilizer dose recommended
is: compost 1000 kg, N 4, P 2 O 5 3, K 2 O 2 kg/10 ares (1 are = 100 m^2 ). The hydroponic
system of cultivation is also prevalent in Korea and Japan. Both nutrient film and
deep flow techniques are used (Park and Kim, 1991).
Table 29.1 Procedure for Perilla cultivation in Hokkaido
Sowing time End of April–early May
Planting field Any kind of soil except for the field of natural growth and also the field in
which Perilla was cultivated the previous year.
Planting density 800 plants/are, row width 60 cm, spacing 20–25 cm.
Sowing 30 ml of seed per are. 68,000 seeds weigh 55 g (100 ml). Sow when the soil
contains enough moisture, lightly cover the seed with the soil and press it
down carefully.
Fertilizer Fertilizer standard (per are): N 1 kg, P 0.65 kg and K 0.66 kg.
Weeding Middle of June–middle of July. Remove the weeds before they grow too
thick when the weather is favourable. Tall weeds must be removed.
Thinning Thinning should be started after the 4th or 5th leaf has appeared and should
be completed before the plants reach a height of 15 cm.
Supplementary If the germination is poor, supplementary sowing is carried out on vacant
sowing hills.
Pest control Chemicals used to control insects such as striated chafer, aphid, spider mite
and cabbage army worm, must not be applied one month before harvesting.
Harvesting Hand or machine cutting applied so as to obtain as much as possible.
Drying Dry the leaves in the sun to a moisture content of about 13%.
(1 are = 100 m^2 ).
Source: (Tanaka et al., 1997).