Levisticum officinale Stratify seed for 1-2 weeks by rolling it up in a damp paper towel in a ziplock bag and placing it in the fridge. This damp chilling period will result in higher and more even germination. Remove from fridge and sow indoors for transplants or sow directly outdoors after last frost. Sow seed .6 cm deep. Transplants can be put out around the last frost date.