Lemon Balm / Sweet Balm
Melissa officinalis
description
Lemon Balm is a vigorous mint relative with softly textured lemon-scented leaves.
benefits
- Edible
- Suitable for containers
How to care for Lemon Balm
sunlight
Lemon balm naturally grows in sunny clearings and along woodland edges. Indoors, give it your brightest window to keep growth compact and leaves fragrant.
Bright light with some direct sun
An east, west, or unobstructed south-facing window works well. Aim for about 4-6 hours of direct sun when possible, especially in winter. It will grow in less light, but may become lanky and less flavorful.
Full sun
Full sun suits a well-watered plant, particularly outdoors or in a cool, airy window. In very hot indoor sun, check moisture more often and move it slightly back from the glass if leaves scorch.
watering
Keep lemon balm evenly moist, but never leave its roots sitting in water. It grows fastest with regular moisture and may wilt quickly when a small pot dries out.
Spring and summer
Water thoroughly about every 2-4 days in bright, warm conditions. Check first: water when the top 1 inch of soil feels dry, then let excess drain away. Hot sun, small terracotta pots, and vigorous new growth can shorten the interval.
Autumn and winter
In lower light or cooler rooms, water roughly every 7-10 days. Let the top 1-2 inches dry, but do not allow the whole root ball to become dusty dry. A larger pot, dense soil mix, or slow growth means it will need water less often.
humidity
Preferred humidity
Lemon balm grows well in ordinary home humidity. This hedgerow herb appreciates moderately moist air, but it is less fussy about humidity than it is about evenly moist soil and good airflow.
It usually tolerates around 30% humidity if it is watered promptly. Very dry air can make leaf edges crisp, cause faster wilting, and leave new leaves smaller, especially near heating or air conditioning.
If indoor humidity stays below about 30%, use a small humidifier nearby or move the pot to a brighter, less drafty room. Avoid stagnant, humid air above 60%, which can encourage powdery mildew.
temperature
Best for leafy growth
Native to southern Europe and western Asia, lemon balm is a hardy perennial but makes its softest, most fragrant leaves in mild conditions. It handles ordinary room temperatures well. Prolonged heat above 27°C (80°F) dries the pot quickly and can encourage flowering.
Established plants can overwinter outdoors in many climates and may die back after frost. Container roots are less protected, so shelter pots from repeated freezing below 0°C (32°F).
nutrition
March - August
Feed potted lemon balm about every 4-6 weeks with a balanced liquid fertilizer at half strength. Apply it to already-moist soil while the plant is making new leaves. Stop feeding in autumn and winter, or when growth slows. Plants growing in the ground usually need only a spring top-dressing of compost.
Nitrogen
Nitrogen supports the leafy growth you harvest. A gentle, balanced feed provides enough without pushing soft, overly lush growth with less fragrance.
soil
Moisture-retentive, well-draining soil
Lemon balm grows best in loose, fertile soil that holds some moisture without becoming soggy. Use a quality potting mix with compost, and add perlite or coarse sand if it feels dense or stays wet for days.
pH 6,0 - 7,5
This is slightly acidic to slightly alkaline, a range that suits most garden soil and standard herb potting mixes. Avoid strongly acidic mixes, and refresh container soil with compost each spring to keep it productive.