Lemon Balm in Zone 5B — Great Plains

Lemon Balm is a garden workhorse in our Zone 5B Great Plains gardens. Its bright, lemony flavor elevates everything from iced tea to roasted chicken. Plus, it's incredibly satisfying to grow your own herbs, especially when they thrive in our prairie soil and intense sunshine.

Our region can throw curveballs: extreme temperature swings and the occasional hail risk. But Lemon Balm is surprisingly resilient. With smart timing and a little attention, you can easily enjoy harvests throughout our 178-day growing season.

Starting Lemon Balm indoors gives you a head start, especially if you're further north in the Plains where our growing season feels even shorter. Begin in early to late March, about six weeks before you want to plant outdoors. Use seed trays with a good seed-starting mix, and keep them warm.

Bottom watering is the best way to keep the soil evenly moist without disturbing the tiny seeds. Once seedlings emerge, make sure they get plenty of light. Remember our Plains springs often have variable temperatures, so keep an eye on your seedlings and adjust their environment as needed.

Transplant your Lemon Balm seedlings outdoors from mid April through mid May. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. This is especially important considering our extreme temperature swings.

Space plants 18-24 inches apart in well-drained soil. Keep an eye on the forecast. Late frosts are always possible in the Plains, so be ready to cover your young plants if needed.

Direct sowing Lemon Balm is a perfectly viable option for us Plains gardeners. Sow seeds from mid April through late July. Soil temperature should be consistently above 60°F for best germination.

Prepare your garden bed by loosening the soil and removing any weeds. Scatter seeds thinly and cover with a light layer of soil. Keep the soil consistently moist until seedlings emerge. Thin seedlings to 18-24 inches apart. Direct sowing is simple, but indoor starting gives you more control over the growing environment.

Lemon Balm needs moderate watering to thrive in our Great Plains climate. While it can tolerate more moisture than some other herbs, it's not drought-tolerant, and our summers can be scorchers. During the hottest part of summer, you might need to water deeply two or three times a week, especially if rainfall is scarce.

Use the "finger test" to gauge soil moisture: stick your finger about two inches deep into the soil. If it feels dry, it's time to water. Aim for about one inch of water per week, either from rainfall or irrigation. Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our low-to-moderate humidity.

Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to yellowing leaves and root rot. A layer of mulch around your plants helps retain moisture and regulate soil temperature, which is crucial in our variable climate.

Lemon Balm is a vigorous grower, so minimal pruning is key to keeping it in check. In midsummer, cut the plant back by about half to prevent it from becoming leggy and encourage bushier growth. This also keeps it producing fresh leaves.

Remove any flower stalks as soon as you see them to prevent the plant from self-seeding. Lemon Balm can be quite aggressive, and you don't want it taking over your garden. As the first frost approaches in mid- October, you can give the plant one final trim before winter.

You can start harvesting Lemon Balm leaves as early as late June, about 70 days after planting. Harvest leaves anytime throughout the growing season, but the flavor is best before the plant starts to flower. Continuous harvest is possible, and actually encourages more growth.

To harvest, simply snip off the leaves you need with scissors or pruners. Avoid taking more than one-third of the plant at a time to allow it to recover. Use the fresh leaves as soon as possible, as they lose their flavor quickly when dried.

As the first frost approaches in mid- October, harvest any remaining leaves. You can use them fresh or freeze them for later use. Even if the plant dies back in winter, it will usually regrow in spring.

Lemon Balm, while generally easy to grow, can present a few challenges in our Zone 5B Great Plains gardens. The top three problems are aggressive spreading, bolting, and powdery mildew.

Aggressive Spreading

• What it looks like: Lemon Balm popping up in areas where you didn't plant it.
• What causes it: Self-seeding and spreading through underground rhizomes.
• How to fix/prevent it: Remove flower stalks before they set seed. Consider growing it in a container to contain its spread. Regularly dig up and divide the plant to keep it under control.

Bolting

• What it looks like: The plant sends up a flower stalk prematurely. Leaves become bitter and tough.
• What causes it: Heat stress and long days can trigger bolting.
• How to fix/prevent it: Plant in a location with partial shade, especially during the hottest part of the day. Keep the soil consistently moist. Harvest regularly to encourage leaf production.

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves and stems.
• What causes it: Fungi that thrive in warm days, cool nights, and moderate humidity.
• How to fix/prevent it: Improve air circulation by spacing plants adequately and pruning. Remove affected leaves. Apply neem oil or potassium bicarbonate sprays.

Great Plains Specific Challenges: Our hot summers and variable rainfall can exacerbate these problems. Consistent watering is crucial to prevent bolting and reduce stress. Good air circulation helps to combat powdery mildew, especially during periods of higher humidity. Regular monitoring and prompt action are key to keeping your Lemon Balm healthy and productive.

Lemon Balm plays well with certain plants in our Plains gardens. It's a good companion for tomatoes because it repels tomato hornworms. Squash also benefits from Lemon Balm's presence, as it can deter squash bugs.

Broccoli and cauliflower thrive near Lemon Balm, as it helps to repel cabbage moths. Avoid planting Lemon Balm near rue, as it can inhibit its growth. Overall, Lemon Balm is a beneficial companion that can help protect your vegetables from pests.