How to Grow Lemon Balm From Seed

Lemon balm is a cool-tolerant perennial, so you have room to be flexible. Start seeds indoors 8 to 10 weeks before your last spring frost, or direct-sow outdoors once the soil has warmed and the danger of hard frost has passed. Because the seeds sprout slowly and unevenly, an indoor start gives you the most control, and a week or two of cold stratification in the fridge beforehand wakes them up more reliably. In mild zones you can also sow in early fall for plants that settle in over winter.

Lemon balm seeds are tiny and need light to germinate, so do not bury them. Press them gently onto the surface of moist, well-drained seed-starting mix or garden soil and leave them uncovered, or dust them with only the thinnest sprinkle of fine soil. Keep the surface evenly moist with a gentle mist or by bottom-watering so the seeds do not wash away, and hold the temperature around 65 to 75F. Be patient, because sprouting is slow and erratic and can take anywhere from 10 days to 3 weeks or more. Once seedlings have a couple of true leaves, thin or space them 18 to 24 inches apart, since each plant grows into a bushy clump.

Lemon balm is famously easy once it is up and growing. Give it full sun to part shade, with a little afternoon shade a bonus in hot climates, and water regularly to keep the soil evenly moist. It rarely needs much feeding, and a light dose of compost in spring is plenty. Pinch and harvest often to keep the plant bushy and full of fresh new leaves, and cut it back hard if it starts to look leggy. Snip off flower stalks as they appear to keep the leaves flavorful and to stop the plant from self-seeding around the garden. Lemon balm is a cold-hardy perennial across USDA zones 3 to 7, dying back over winter in the North and returning each spring; in the hot lower South, like Florida and the Gulf Coast, it grows fast but can flag in peak summer heat, so give it afternoon shade and steady water and it will bounce back as things cool.

Lemon balm is a friendly herb-garden neighbor, and its little flowers draw in bees and other helpful insects when you let a few bloom. These four make especially good companions, and you can add any of them in one click:

You can start snipping sprigs as soon as the plant is established and bushy, taking no more than about a third at a time. For the strongest lemon scent, harvest in the morning after the dew dries and before the plant flowers. Regular cutting is the best thing you can do for lemon balm, since it encourages a fresh flush of tender new leaves. Over a season you can cut a healthy clump back several times.

Lemon balm brings a soft, lemony, faintly minty note to the kitchen. It is best known steeped fresh or dried into a gentle herbal tea, hot or iced, and it has a long traditional place in the tea garden. Beyond the cup, tear the fresh leaves into fruit salads, summer drinks, and lemonade, scatter them over fish or chicken, or use them as a fragrant garnish. The leaves are at their most aromatic before the plant flowers.

• Slow, patchy germination: this is normal for lemon balm. Surface-sow so seeds get light, cold-stratify the seed for a week or two first, and keep the surface evenly moist and around 65 to 75F.
• Self-seeding everywhere: trim off flower stalks before they set seed, or grow the plant in a pot or bordered bed to keep it contained.
• Powdery mildew: a white dusty film in humid or crowded conditions. Space plants for airflow, water at the base, and cut the plant back hard to push clean new growth.
• Leggy, sparse plants: usually too little light or overdue for a trim. Give more sun and harvest or shear regularly to keep the clump bushy.