Lemon Balm in Zone 7A — Midwest

Lemon Balm is a fantastic herb for any Midwest garden. Its light, lemony flavor brightens up teas, salads, and even desserts. Plus, it's incredibly satisfying to grow your own herbs, especially with our fertile soil and adequate summer heat, which helps Lemon Balm thrive.

Midwest weather can be unpredictable, with cold winters and the occasional summer heat spell. But don't worry, with a little planning and attention to timing, you can easily grow Lemon Balm during our 193-day growing season. We'll make sure you get the most from your plants.

Starting Lemon Balm indoors isn't strictly necessary here in the Midwest, but it can give you a head start. If you're itching to get gardening before the weather settles, aim to sow seeds indoors from mid February through mid March, roughly six weeks before you plan to transplant.

Use seed trays with a good seed-starting mix and keep them in a warm spot with plenty of light – a sunny windowsill or under grow lights works well. Don't forget to water from the bottom to encourage strong root growth! Remember, our springs can be moderate-to-late, so be patient.

Once the danger of frost has passed – generally early April through early May – 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. This helps them adjust to the Midwest weather.

Choose a spot with full sun to partial shade and space the plants about 18-24 inches apart. Keep an eye on the forecast; we sometimes get unexpected cold snaps, so be ready to cover your young plants if needed.

Direct sowing Lemon Balm is a simple and effective method, especially if you're not in a rush. You can sow seeds directly into the garden from early April through late July. This gives you a wide window to work with.

Make sure the soil is well-prepared and the temperature is consistently warm enough for germination. Plant seeds about ¼ inch deep and keep the soil moist. Thin seedlings to 18-24 inches apart once they emerge. The downside? You'll need to keep the area weeded until the seedlings are established.

Lemon Balm prefers moderate watering, which fits right in with our Midwest climate. Unlike some herbs that thrive on neglect, Lemon Balm appreciates consistent moisture, especially during our moderate-to-hot summers.

During the peak growing season, aim to water deeply about once a week, providing roughly 1 inch of water. Use the "finger test" – if the top 2 inches of soil feel dry, it's time to water. With our moderate-to-humid conditions, it's generally better to water at the base of the plant to avoid promoting fungal diseases.

Watch for signs of underwatering, like wilting leaves, or overwatering, such as yellowing leaves. A good layer of mulch can help retain moisture and regulate soil temperature, a great way to combat heat spells. Remember, our wet summers often mean you can ease up on watering, but don't rely entirely on rainfall.

Pruning Lemon Balm is pretty straightforward. You don't need to do much, but a little attention goes a long way.

In midsummer, cut the plant back by about half to prevent it from becoming leggy and encourage bushier growth. Also, remove any flower stalks as they appear; this prevents self-seeding, which Lemon Balm is known for doing aggressively. As the first frost approaches in mid- October, you can cut the plant back to a few inches above the ground. It will return in the spring.

You can start harvesting Lemon Balm leaves as soon as the plant is established, usually around mid June. The plant will continue producing through late October. The best flavor comes from leaves harvested before the plant flowers, so keep an eye out.

To harvest, simply snip off the top leaves and stems, taking no more than a third of the plant at a time. This encourages continued production. As we approach the first frost in mid- October, harvest as much as you can and consider preserving it by drying (though the flavor fades). Use fresh lemon balm as often as you can.

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

Aggressive Spreading

• What it looks like: Lemon Balm popping up in unwanted areas of your garden, spreading beyond its intended space.
• What causes it: Lemon Balm self-seeds readily and can spread quickly through underground rhizomes. Our fertile soil only encourages it.
• How to fix/prevent it: Plant Lemon Balm in a container to contain its spread. Remove flower stalks before they go to seed. Regularly pull up 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, which we can experience during our summer heat spells.
• How to fix/prevent it: Provide shade during the hottest part of the day. Ensure consistent moisture. Remove flower stalks as soon as they appear to encourage leaf production.

Powdery Mildew

• What it looks like: A white or grayish powdery coating on the leaves, stems, and sometimes fruit.
• What causes it: Powdery mildew thrives in warm days, cool nights, and moderate humidity – conditions we often experience in the Midwest.
• How to fix/prevent it: Improve air circulation by spacing plants adequately and pruning. Remove affected leaves. Use neem oil or potassium bicarbonate sprays. A milk spray (1 part milk to 9 parts water) can also be effective.

Midwest Specific Challenges: Our combination of moderate-to-hot heat, moderate-to-humid humidity, and wet-summer rainfall can create ideal conditions for powdery mildew and encourage aggressive spreading. Monitor your plants closely, especially during periods of high humidity, and take preventative measures to keep them healthy.

Lemon Balm makes a good companion plant for several vegetables in the Midwest garden. It's said to repel certain pests.

Good companions include tomatoes, squash, broccoli, and cauliflower. Lemon Balm can help deter tomato hornworms and squash bugs, while also attracting beneficial insects that prey on cabbage worms that often plague broccoli and cauliflower. I haven't found any bad companions to avoid.