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How to Grow Lemon Balm Indoors

The Spruce / Krystal Slagle

Lemon balm is an ancient herb native to southern Europe that is closely related to mint. It features similar wrinkled, oval-shaped leaves and boasts a fresh citrusy smell and scent that many home cooks love to add to salads, soups, and more. Lemon balm also has a unique medicinal history—its use as a curative can be traced back to ancient Greece and Rome, where its leaves were used in a variety of tonics and teas, and its essential oils were extracted to aid with digestive issues.

The versatile herb is a rapid grower outdoors—after planting in early spring, it’s not unusual to see a lemon balm plant grow to over a foot tall (sometimes, even two!) in just a single season. For that reason, many gardeners choose to plant lemon balm in containers, whether grown indoors or out, in an attempt to control its invasive nature. Like many other herbs, lemon balm prospers best outdoors but can be grown successfully inside as well, as long as proper attention is paid to its unique needs.

Botanical name Melissa officinalis
Common name Lemon balm
Plant type Herbaceous perennial
Mature size 1.5–2 ft. tall, 1.5–3 ft. wide
Sun exposure Full sun, partial shade
Soil type Well-drained
Soil pH Neutral to acidic
Bloom time Summer
Flower color White, pale yellow
Hardiness zones 3–7 (USDA)
Native area Europe
Toxicity Non-toxic

Lemon Balm Care

A hardy perennial shrub that is tolerant to USDA zones 3 through 7, lemon balm can be grown year-round indoors, as well as outdoors in warmer climates. Even if you’re seasoned at growing lemon balm outdoors, there are several things you’ll need to modify slightly in order to successfully grow it in your home. Lemon balm will need significantly more sunlight when planted indoors and can be more susceptible to afflictions like powdery mildew and root rot, not to mention browning leaves, which can indicate issues like cold air or excessive sunlight.

Lemon balm also has the tendency to bolt if exposed to too much water or not maintained properly. If you notice small flower buds beginning to form on your lemon balm plant, take care to pinch them off quickly. Once the plant blooms, the flavor of its leaves will change, causing them to taste bitter. To cook with your lemon balm, harvest the leaves as soon as the plant is established and putting out regular new growth. Take care to never remove more than about 25 percent of the plant’s mass at any one time.

Light

In both indoor and outdoor environments, lemon balm loves a sunny spot. However, unlike an outdoor lemon balm plant—which can tolerate a bit of shade—those planted indoors need ample sunlight, at least five to six hours a day. Place your herb containers near a windowsill that gets ample light throughout the day. If you notice your plant getting a lot of harsh direct rays or turning brown on its leaves, rotate it periodically to avoid burning.

Lemon balm plants prefer a slightly sandy, well-drained soil. Most basic potting soils will work just fine, but if you find your mixture is a bit dense or stays too moist between watering, combine it with sand or a drier soil varietal like a cactus mix. Additionally, the pH of your soil should be neutral to acidic, with a specific level between 6.7 to 7.3 providing the best environment. When selecting a container to house your lemon balm plant in, choose a pot with ample drainage holes to minimize the risk of the herb becoming waterlogged or the roots rotting. One made of clay or terracotta can also be helpful, as the porous material will help to wick any added moisture from the soil.

Water

When it comes to watering your lemon balm plant, always err on the side of under-watering, rather than over-watering. The reason: Like many herbs, lemon balm plants can recover easily from wilt (created by thirst) but will quickly die or bolt if watered too much. Your exact watering schedule will depend on the environment in your home and the plant’s sun exposure levels, but a good general rule of thumb is to water in small quantities (do not saturate) as soon as the first inch or so of soil in the pot has dried up.

Temperature and Humidity

When it comes to its indoor environment, the lemon balm plant is not particularly picky. In general, it’s best to keep your herb away from any drafty air that is too cold or too hot, such as in front of an air conditioner or next to a radiator. Additionally, lemon balm does not need a humid environment to thrive, so you won’t have to worry about increasing the moisture levels in the air with a humidifier.

Fertilizer

While lemon balm does not require additional feeding beyond what nutrition its soil provides, you can treat it with a light liquid fertilizer every few weeks to encourage growth. Keep in mind, fertilizing some herbs has been known to decrease the potency of their scent and/or flavor—if you’re growing lemon balm specifically for cooking, you can likely skip fertilizing it and still be just fine.

Propagating Lemon Balm

Lemon balm is what’s known as a self-seeding plant, meaning outdoors it spreads its seeds to further its growth (hence why some gardeners consider it invasive). However, most indoor growers won’t see their plants set seeds. Instead, it’s advised to discard your lemon balm plant if it bolts (goes to flower), in part because the taste and potency of the leaves will be diminished. It’s easy to start new plants from packaged seeds (they will germinate in a little over a week) or simply buy new seedlings at your local garden center.

How to Grow Lemon Balm From Seed

Lemon balm seeds need ample light in order to germinate and grow. To start your plant from seed, begin them in a shallow pot or dish, barely covering the seeds with more than a sprinkle of soil (this should be done about six to eight weeks before the last frost if you want to transplant the herb outdoors). Expose the dish to ample light and just enough water to keep them from drying out (its helpful to use a spray bottle instead of a watering can for this stage) and germination should take place in 10–14 days. Once the seedlings are large enough to handle easily, you can transplant them into a traditional pot with soil.

Common Diseases

Lemon balm has no serious pest issues, but can be susceptible to powdery mildew. To prevent it from developing, plant your lemon balm with ample room separating it from other plants to allow for good air circulation. If powdery mildew does develop, remove the infected leaves, and treat with a mild fungicide.

Successfully grow lemon balm indoors with tips for germinating from seed, maintaining the proper conditions, and harvesting.

Lemon Balm

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Description

Lemon balm is an upright, bushy, herbaceous perennial. Leaves are light green, arrowhead shaped, somewhat hairy and coarse textured. Lemon balm grows to about 10-24 inches tall. Flowers may be white, pale yellow or pink.

Culture

Lemon balm can be grown in full sun to partial shade in soils that are moist but well drained. It can be propagated by seeds, division or stem cuttings. Lemon balm is often confused with mint in regards to how it grows and spreads in the garden. While mint can spread rapidly by underground stems, lemon balm spreads by setting lots of seed and can, if allowed to go unchecked start to overtake the garden. To prevent spreading, prune flowering stalks before they have a chance to set seed. To keep plants vigorous, thin plants out in mid-summer by cutting out stems to open up the plant to better air circulation. Lemon balm can also be cut back to about one-half its height to encourage fresh, vigorous new growth. Watering after this heavy pruning helps the plant recover quicker.

Harvesting

Stems can be cut as needed anytime during the season preferably before flowering. While fresh lemon balm is superior to dried, cut stems can be bundled, hung in a warm, dark, well ventilated location to dry. After drying, strip leaves from stems and store in a sealed container. Leaves can also be frozen for later use.

Lemon balm can be used to flavor many different types of dishes. It can be added to salads, stews, soups, fish, pork and egg dishes. It is also used in making jellies, teas and vinegars and to compliment fruit.

Popular Varieties

‘Compacta’ – A more compact form of lemon balm that is also sterile which means the flowers do not set viable seed. This help to prevent spreading in the garden.

‘Aurea’ – Foliage is an attractive variegated yellow in spring and fall.

Lemon Balm You may also like: Description Lemon balm is an upright, bushy, herbaceous perennial. Leaves are light green, arrowhead shaped, somewhat hairy and coarse textured. Lemon balm