Lemon Balm in Zone 3B — Great Plains

Lemon Balm is a fantastic herb for Plains gardeners. The lemony, minty flavor brightens teas, salads, and even desserts. Plus, it's incredibly satisfying to grow your own herbs, especially when you can just snip off what you need right before using it.

Our extreme weather and short growing season here can be challenging, but Lemon Balm is surprisingly adaptable. With a little planning, you can easily enjoy a harvest from late July through late September (within our 118-day growing season).

Starting Lemon Balm indoors is an option, especially if you want a head start. Begin in early to late April, about six weeks before you plan to transplant.

Use seed trays with a good seed-starting mix. Keep them warm and provide plenty of light – a simple shop light works great. Remember to water from the bottom to avoid damping off. Given our variable spring weather, starting indoors gives you more control over the initial growth.

Transplant your Lemon Balm seedlings outdoors from mid May through mid June, after hardening them off. Hardening off is essential in our climate; gradually expose the seedlings to outdoor conditions for about a week.

Plant them 18-24 inches apart. Keep an eye on the weather forecast; a late frost or a hailstorm can be devastating to young plants. Wind protection is also essential to prevent damage.

Direct sowing Lemon Balm is a viable option, especially if you're a bit late getting started. Sow seeds mid May through late June.

Prepare the soil by loosening it and removing any weeds. Lemon Balm needs a soil temperature of at least 60°F to germinate. Plant the seeds shallowly, and keep the soil consistently moist until they sprout. Thin seedlings to 18-24 inches apart. Direct sowing eliminates the need for transplanting, but you'll need to be vigilant about weed control.

Lemon Balm needs consistent moisture, but it's not drought-tolerant, which can be tricky in our Plains climate. During the hot summer months, aim for about an inch of water per week.

Use the finger test to check the soil moisture: stick your finger about two inches deep. If it feels dry, it's time to water. Water at the base of the plant rather than overhead to minimize the risk of fungal diseases in our low-to-moderate humidity.

Signs of underwatering include wilting leaves and slow growth. Overwatering can lead to yellowing leaves and root rot. A layer of mulch, like straw or wood chips, helps retain moisture and regulate soil temperature, which is especially helpful with our extreme temperature swings.

Pruning Lemon Balm is pretty straightforward. Cut the plant back by about half in midsummer to prevent it from becoming leggy and encourage new growth.

Remove any flower stalks as soon as you see them. Lemon Balm is an aggressive self-seeder, and removing the flowers prevents it from taking over your garden. As the first frost approaches in mid- September, you can give the plant one final trim to tidy it up for the winter.

You can start harvesting Lemon Balm leaves as early as late July, and continue through late September. The best flavor comes from leaves harvested before the plant flowers.

Simply snip off the leaves you need, being careful not to damage the main stem. Regular harvesting encourages the plant to produce more leaves. As the first frost approaches, harvest as much as you can and consider preserving it by drying or freezing.

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

Aggressive Spreading

• What it looks like: Lemon balm popping up everywhere in your garden, even in places you didn't plant it.
• What causes it: Lemon balm spreads easily through seeds and rhizomes.
• How to fix/prevent it: Remove flower stalks before they set seed. Consider growing it in a container to restrict its spread.

Bolting

• What it looks like: The plant sends up a flower stalk prematurely, and the leaves become bitter or tough.
• What causes it: Triggered by heat or drought stress.
• How to fix/prevent it: Plant in partial shade, especially in the hotter parts of the Plains. Keep the soil consistently moist. Remove flower stalks as soon as you see them.

Powdery Mildew

• What it looks like: White or grayish powdery coating on the leaves.
• 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 properly. Remove affected leaves. A milk spray (1 part milk to 9 parts water) can be surprisingly effective.

Great Plains Specific Challenges: Our hot summers can cause bolting and drought stress. Consistent watering is key, and providing afternoon shade can help prevent bolting. The wind can also be tough on Lemon Balm, so plant it in a sheltered location or provide wind protection.

Lemon Balm plays well with several other garden plants. Tomatoes, squash, broccoli, and cauliflower all benefit from being planted near Lemon Balm. Its scent can help repel certain pests, like cabbage moths, that often plague brassicas. There are no known bad companion plants.