The white cedar, or Thuja occidentalis, is a hardy shrub-like tree that can withstand minimum winter temperatures down to about -35 to -40 degrees Fahrenheit. Part of the Cypress family, the white cedar is evergreen, long-living and tall, growing to 50 feet high or more at maturity. White cedar seedlings grow very slowly, gaining only an average of 3 inches in height each year. Getting white cedar seeds to germinate and the seedlings to grow can be difficult, so you must provide the right conditions to ensure success.
Place the white cedar seeds in a container filled with a handful of damp sand or topsoil. Store the seeds in the refrigerator for at least two or three months.
Fill a seed tray with moist topsoil mixed with organic compost or rotted bark mulch, with an optimal soil pH of 6.6 to 7.2. Sow the seeds in March, about 1- to 2-inches deep.
Maintain daytime temperatures between 84 and 86 degrees Fahrenheit and nighttime temperatures at 68 degrees Fahrenheit.
Place the seeds in bright, indirect sunlight. Keep the soil moist by watering it gently or misting it with water each day.
Move the seedlings into full light when they germinate and begin to sprout. Continue to water or mist daily. Transplant the seedlings outdoors in the spring when they reach about 12 inches tall and have strong, well-developed roots.