Lemon Balm in Zone 6A — Great Plains

Lemon Balm is a workhorse herb for Great Plains gardens. Its bright, citrusy flavor is fantastic in teas, salads, and even desserts, offering a refreshing taste of summer even when the wind is howling. Plus, it's a reliable perennial that comes back year after year, giving you a steady supply of fresh herbs.

Like any gardening venture here, growing Lemon Balm in our region requires a bit of planning. We deal with extreme temperature swings and variable rainfall, but with a growing season around 188 days, you have a good window to get it established and enjoy its bounty.

Starting Lemon Balm indoors from late February through mid March gives you a head start on the season. This is useful if you want a more mature plant ready to go as soon as the weather breaks. Otherwise, direct sowing works just fine.

Use seed trays or small pots filled with a good seed-starting mix. Keep the soil consistently moist, but not soggy – bottom watering helps prevent damping-off. Place the trays in a warm spot (around 70°F) and provide plenty of light, either from a sunny window or a grow light. Remember, our springs can be variable, so starting indoors gives you more control.

Transplant your Lemon Balm seedlings outdoors from mid April through mid May, after the danger of hard frost has passed. Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the wind and temperature changes.

Choose a spot with full sun to partial shade and space the plants 18-24 inches apart. Our prairie soil is generally fertile, but adding some compost at planting time will give them an extra boost. Keep an eye on the weather forecast – a late cold snap can still happen, so be ready to cover your transplants if needed.

Direct sowing Lemon Balm is a simple and effective method, especially if you're not in a rush. Sow seeds from mid April through late July. The later you sow, the smaller the plant will be in the first year, but it will still come back the next.

Prepare the soil by loosening it and removing any weeds. Sow seeds thinly and cover them with a light layer of soil. Keep the soil consistently moist until the seedlings emerge. Thin the seedlings to 18-24 inches apart. Direct sowing avoids transplant shock, but the plants will take longer to mature.

Lemon Balm needs moderate watering, especially during our hot Plains summers. While it can tolerate a bit more moisture than some herbs, it definitely isn't drought-tolerant. Finding the right balance is key.

During the spring and fall, when temperatures are milder and rainfall is more frequent, water deeply once or twice a week, providing about 1 inch of water each time. In the heat of summer, especially if we're experiencing a dry spell, you might need to water every other day, or even daily, to keep the soil consistently moist. Use the "finger test" – stick your finger into the soil about 2 inches deep. If it feels dry, it's time to water.

Water at the base of the plant to avoid wetting the leaves, which can encourage fungal diseases, even with our low-to-moderate humidity. Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to yellowing leaves and root rot. To help retain moisture and suppress weeds, mulch around your Lemon Balm plants with a layer of straw or wood chips.

Pruning Lemon Balm is pretty straightforward. The main goal is to keep it from getting too leggy and to prevent it from spreading too aggressively. This herb is known for self-seeding, so stay on top of it!

Cut the plant back by about half in midsummer. This encourages new growth and keeps it looking tidy. Also, remove any flower stalks as soon as you see them to prevent self-seeding. As the first frost approaches around mid- October, you can leave the plant alone. It will die back in the winter and regrow in the spring.

You can start harvesting Lemon Balm leaves as soon as the plants are big enough, usually starting in late June and continuing through late October. The leaves have the best flavor before the plant flowers, so harvest regularly to encourage continued leaf production.

To harvest, simply snip off the leaves with scissors or pinch them off with your fingers. Avoid taking more than one-third of the plant at a time to allow it to recover. Lemon Balm is best used fresh, as it loses much of its flavor when dried. As the first frost approaches, harvest any remaining leaves and use them fresh or freeze them for later use.

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

Aggressive Spreading

• What it looks like: Lemon Balm popping up in unwanted areas of your garden.
• What causes it: Self-seeding and spreading roots.
• How to fix/prevent it: Remove flower stalks before they set seed. Consider growing Lemon Balm in a container to contain its spread. 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: Heat stress or drought stress.
• How to fix/prevent it: Provide shade during the hottest part of the day. Keep the soil consistently moist. Harvest leaves regularly to delay bolting.

Powdery Mildew

• What it looks like: A white or grayish powdery coating on the leaves and stems.
• What causes it: Fungal disease that thrives in warm days, cool nights, and moderate humidity.
• How to fix/prevent it: Improve air circulation by spacing plants properly. Remove affected leaves. Apply neem oil or potassium bicarbonate sprays.

Great Plains Specific Challenges: Our hot summers and variable rainfall can exacerbate bolting and powdery mildew. Consistent watering and providing afternoon shade can help mitigate these issues. The wind can also contribute to the spread of powdery mildew spores, so good air circulation is essential.

Lemon Balm is a helpful companion plant for several vegetables in the Great Plains garden:

• Tomato: Lemon Balm repels tomato hornworms and other pests that can damage tomato plants.
• Squash: It can deter squash bugs and vine borers, which are common problems for squash in our region.
• Broccoli and Cauliflower: Lemon Balm can help repel cabbage moths, protecting these brassicas from caterpillar damage.

Avoid planting Lemon Balm near any plants that prefer very dry soil, as its moderate watering needs might create too much moisture for them.