Lemon balm (Melissa officinalis) is a versatile, easy-to-grow herb, cherished for its distinct lemony scent and its applications in both culinary and medicinal practices. As a member of the mint family, its robust nature and aromatic leaves make it a popular and rewarding choice for home gardeners.
Optimal Planting Times
Starting lemon balm seeds indoors extends the growing season and allows for an earlier harvest. The ideal time is 6 to 8 weeks before your last anticipated frost date. This allows delicate seedlings to develop in a protected environment, shielding them from unpredictable outdoor conditions. Adequate lighting, such as from grow lights or a bright south-facing window, is important to prevent leggy growth.
For direct sowing outdoors, wait until all danger of frost has passed in spring. Soil temperatures should be 60 to 70°F (15 to 21°C) for optimal germination. While spring is the most common period for direct seeding, lemon balm can also be sown in late summer or early fall in milder climates, allowing the plants to establish before overwintering.
Planting Lemon Balm Seeds
Lemon balm seeds are small and do not require pre-treatment. They germinate best when exposed to light, so a thin covering of soil or vermiculite is sufficient. For indoor starts, a light, well-draining seed-starting mix is ideal.
When planting, lightly press seeds onto the soil surface or cover with about 0.5 cm of soil. If direct sowing outdoors, space seeds 3 to 6 inches apart, or sow in small groups for later thinning. Maintain consistent soil moisture during germination, but avoid waterlogging. A misting bottle or bottom watering prevents disturbing seeds. Germination typically occurs in 7 to 14 days at 65 to 75°F (18 to 24°C).
Nurturing Young Lemon Balm Plants
Once lemon balm seeds have germinated, adequate light is important for healthy seedling development. Outdoor plants thrive in full sun, while indoor seedlings require bright light or grow lights to prevent stretching. Maintain consistent soil moisture for young plants, reducing frequency as they mature, but ensuring the soil never dries out completely.
Thinning is necessary for proper growth and air circulation. Thin seedlings to a final spacing of 12 to 18 inches apart. For indoor seedlings, hardening off is an important process that gradually acclimates them to outdoor conditions over one to two weeks before transplanting. Once hardened off and the weather is suitable, indoor seedlings can be transplanted outdoors.