Lemon Balm in Zone 5A — Midwest

Lemon Balm is a fantastic addition to any Midwest garden. Its bright, citrusy flavor elevates teas, salads, and even desserts, and it thrives in our fertile soil. Plus, there's something deeply satisfying about snipping fresh herbs from your own backyard to brighten up a meal, especially after a long winter.

Our Midwest weather can be unpredictable, with late frosts in spring and summer heat spells, but Lemon Balm is fairly hardy. With a 157-day growing season, you'll have plenty of time to enjoy this herb if you plan accordingly.

Starting Lemon Balm indoors isn't strictly necessary in the Midwest, but it can give you a head start, especially if you're eager for an early harvest. If you want to get a jump on the season, aim to sow seeds indoors from mid-March through early April, about six weeks before you intend to transplant them outside.

Use seed trays or small pots filled with a good seed-starting mix. Keep the soil consistently moist by bottom watering (set the tray in a shallow dish of water and let the soil absorb it from the bottom). Place the trays in a warm spot with plenty of light – a sunny windowsill or under grow lights will do. Remember that our spring can be variable, so starting indoors protects against those unexpected cold snaps.

Once the danger of frost has passed – typically early to late May in the Midwest – it's time to transplant your Lemon Balm seedlings outdoors. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. Start with an hour or two of shade and increase the time and sunlight each day.

Choose a spot with full sun to partial shade and space the plants 18-24 inches apart. Midwest springs can be wet, so ensure the soil drains well. If we're having a particularly dry spell, water the transplants in well to help them establish.

Direct sowing Lemon Balm is a straightforward option in the Midwest. You can sow seeds directly into the garden from early May through mid-July. This works well since our fertile soil warms up nicely by May.

Prepare the soil by loosening it and removing any weeds. Sow the seeds shallowly and keep the soil consistently moist until they germinate. Thin the seedlings to 18-24 inches apart once they're a few inches tall. Direct sowing is a good option if you don't have space or equipment for indoor seed starting, but it does mean a later harvest.

Lemon Balm appreciates consistent moisture, but it doesn't like to be waterlogged. In the Midwest's moderate-to-humid climate, a good rule of thumb is to water deeply about once a week, providing around 1 inch of water. During summer heat spells, you might need to increase watering to two or three times a week.

Use the "finger test" to check the soil moisture before watering: stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water. Aim to water at the base of the plant rather than overhead to minimize the risk of fungal diseases in our humid conditions.

Signs of underwatering include wilting or yellowing leaves, while overwatering can lead to root rot. A layer of mulch around the base of the plant can help retain moisture and suppress weeds, which is especially helpful given our wet summers.

Pruning Lemon Balm is simple but important for maintaining its shape and preventing it from becoming too aggressive. In midsummer, cut the plant back by about half to encourage bushier growth and prevent it from becoming leggy.

Regularly remove any flower stalks that appear. This prevents the plant from self-seeding and becoming invasive, which can definitely be a problem in our fertile Midwest gardens.

As the first frost approaches in early October, you can give the plant one final trim. Leave some foliage to help it overwinter, as Lemon Balm is hardy and will come back next spring.

You can start harvesting Lemon Balm leaves as soon as the plant is established, usually from early July through mid-October in the Midwest. The leaves have the best flavor before the plant flowers, so keep an eye out for those flower stalks and remove them.

To harvest, simply snip off the leaves you need with scissors or pruners. Avoid taking more than a third of the plant at any one time to ensure continued production. Lemon Balm is best used fresh, as it loses its flavor when dried.

As the first frost approaches in early October, harvest any remaining leaves. You can use them fresh or make a batch of Lemon Balm tea to enjoy throughout the winter.

Here are some common problems you might encounter with Lemon Balm in the Midwest:

Aggressive Spreading

• What it looks like: Lemon Balm popping up in unexpected places throughout your garden.
• What causes it: This herb spreads easily through both seeds and underground runners. Our fertile Midwest soil only encourages this.
• How to fix/prevent it: Plant Lemon Balm in a container to restrict its roots, or be diligent about removing flower stalks to prevent seed dispersal. Regularly pull up any unwanted seedlings.

Bolting

• What it looks like: The plant sends up a flower stalk prematurely, and the leaves become bitter or tough.
• What causes it: Bolting is often triggered by heat stress, especially during our summer heat spells.
• How to fix/prevent it: Provide some afternoon shade during the hottest part of the day. Ensure the plant receives consistent moisture. Regularly prune flower stalks to encourage leaf production.

Powdery Mildew

• What it looks like: A white or grayish powdery coating on the leaves and stems.
• What causes it: Powdery mildew thrives in warm days, cool nights, and moderate humidity, which we often experience in the Midwest.
• How to fix/prevent it: Improve air circulation by spacing plants adequately. Remove affected leaves promptly. Spray with neem oil or a milk solution (1 part milk to 9 parts water).

Midwest Specific Challenges: The moderate-to-hot heat and moderate-to-humid humidity of the Midwest can create ideal conditions for powdery mildew and encourage bolting. Be vigilant about providing adequate water and shade during hot spells, and ensure good air circulation to prevent fungal diseases.

Lemon Balm makes a good companion plant for several vegetables in the Midwest garden. It helps repel certain pests that can plague our crops.

Good companions include tomatoes, squash, broccoli, and cauliflower. Lemon Balm repels tomato hornworms and squash bugs, and it can deter cabbage moths from attacking broccoli and cauliflower.

Avoid planting Lemon Balm near rue, as it can inhibit its growth. Also, be mindful of its aggressive spreading habit and don't plant it too close to delicate herbs or vegetables that might be easily overtaken.