Japanese perilla, or shiso, features prominently in the cuisine of eastern Asia both as an herb and edible green. The species grows vigorously and will quickly send up a clump of 24-inch-tall stems lined with red or green, frilly-edged leaves, which have a strong herbal taste reminiscent of fennel. Japanese perilla grows well from seed and requires virtually no care once established, but the flowers must be snipped off before turning to seed to keep the plant from becoming invasive.
Begin processing the Japanese perilla seeds one week before sowing them. Wrap the seeds in a moistened paper towel and place the paper towel inside a sealable plastic bag. Store the seeds in a refrigerator for one week to cold stratify them.
Combine equal parts compost and potting soil. Fill small, 3- to 4-inch peat pots with the mixture.
Place the peat pots on a nursery tray before moistening the soil since the pots become fragile once wet. Water each pot of soil with 1/8 cup of water.
Sow two Japanese perilla seeds in each pot by pressing the seeds into the surface of the soil. Sprinkle a scant layer of sand over each pot to anchor the seeds while providing plenty of light to prompt germination.
Place the nursery tray of peat pots on a warming mat set to between 18.3 and 21.1 degrees Celsius. Provide them with a source of bright light.
Mist the Japanese perilla seeds with a spray bottle every few days to keep the top 1/4 inch of soil moist at all times. Watch for germination in one to two weeks. Thin the seedlings to one per pot once they produce a set of mature leaves.
Plant the peat pots outdoors in full sun or partial shade once the seedlings reach at least 4 inches in height and have two or three sets of mature leaves. Space the plants 3 feet apart to provide ample room.
Wash your hands after handling Japanese perilla seeds since they are mildly toxic to humans.