How to Grow Lavender from Seed
(1) 6-12 WEEKS FROM FROST-FREE PLANTING TIME: Sow seeds in trays indoors about 6-12 weeks before the traditional outdoor planting time (in northern climates, plant seeds indoors roughly late March or any time in the month of April). Use a commercially-sterilized soil especially formulated for starting seeds (pH neutral between 6.7 and 7.3 is best). We like Pro-Mix Organic Seed-Starting Mix. Never use soil taken from your garden, as it may contain pathogens or parasites which can kill fragile seedlings. Sprinkle the seeds on top of the soil. If using a plastic seedling tray, plant one seed per slot. If planting in a division-free container, space the seeds 1/2 to 1 inch (1.27 to 2.54 cm) apart. Gently press the seeds into the soil (no deeper than 1/8 inch).
(2) SOIL TEMPERATURE IS CRITICAL: For an optimum germination rate, keep the soil temperature around 21 degrees (C) [70F]. We recommend putting those seed trays on a heating pad, available from most garden supply centres or mail order.
(3) LIGHTLY WATER THE SOIL. Keep the growing soil damp but not soggy, and water the seeds in the morning so that the soil can dry during the day. Soil that is too damp and cool will invite fungus to grow, and fungus will destroy your seeds.
(4) GIVE SPROUTED SEEDS PLENTY OF LIGHT. 16-18 hours per day under a growing light is ideal, but if you do not have a growing light, then after the seeds sprout, move the seed trays to a location which receives plenty of direct sunlight. If no such location is available and you do not have a growing light, then a third option is to place a fluorescent light above the seedlings and allow them to sit in the artificial light for at least 16 hours a day.
(5) TRANSPLANT TO A SMALL POT. Once your plants have six or more leaves, it’s time to put them into a small pot about 2” (5 cm) in diameter, filled with fresh potting soil.
(6) FINAL STEP: Once your seedlings are about 3 inches (7.5 cm) tall and daytime temperatures consistently remain above freezing, you can then “harden them” by placing them outside for increasing amounts of exposure to the outdoor environment. Start by putting them outside in a shady area; then increase the amount of time in the sun each day, but bring them inside at night. After all danger of frost has passed, the seedlings can be planted in the ground in well-drained soil with full sun.
(7) ADDITIONAL RECOMMENDATIONS:
a. Seedlings will develop into hardier, more attractive plants if you do not allow them to blossom the first year. Instead, pinch off the top part of each branch or blossom head. This will encourage vigorous root growth, as well as new branches will sprout from within the core of the plant, giving it a richer, fuller appearance. You can let your lavender fully blossom from the second year on.
b. By way of a fertilizer, once you have planted your starter plants in the ground, you can then sprinkle one tablespoon each of a time-released, all-purpose fertilizer and if you have clay soil, also a tablespoon of pelletized lime. Repeat this process once per year in the spring. Fertilizing lavender is optional; they’ll do just fine if you forget. As long as your lavender plants have a sunny, well-drained location, they will be fine. For the most part, lavender thrives on neglect.
c. Lavender is NOT an indoor plant; it needs to be planted outside. Do not move lavender plants past the 15th of September in northern climates (especially very young ones). Plants need time to establish roots prior to winter. Also, do not prune lavender plants in the fall, except for cosmetic removal of old flower stalks. (Pruning of lavender is optional, but if undertaken, should be done in the springtime only -- no more than 1/3 the length of each branch).
d. For additional information, see our “Lavender 101” flyer at www.lavendercanada.com (scroll to the bottom of the home page). Also follow along on our Facebook page for year-round care instructions: https://www.facebook.com/seafoamlavender/