Lemon Balm in Zone 6A — Midwest

Lemon Balm is a fantastic herb to have in your Midwest garden. Its citrusy, minty flavor brightens up teas and salads, and it's incredibly easy to grow in our fertile soil. Plus, the bees absolutely love it, which is always a win for a healthy garden ecosystem.

We all know Midwest weather can be a bit unpredictable, especially in the spring, and we sometimes get those summer heat spells. But don't worry, Lemon Balm is pretty resilient, and with our 178-day growing season, you'll have plenty of time to enjoy a bountiful harvest.

Starting Lemon Balm indoors is an option, but honestly, it's not usually necessary for us Midwest gardeners. However, if you're eager to get a head start or want to ensure you have a few established plants ready to go, you can start seeds indoors from early to late March, about six weeks before our typical transplanting window.

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 great. Don't forget to bottom-water your seedlings to encourage strong root growth. Keep in mind that our spring can be moderate-to-late, so be patient and don't rush the transplanting process.

Once the danger of frost has passed – usually mid April through mid May around here – it's time to transplant your Lemon Balm seedlings outdoors. Before planting, be sure to harden them off by gradually exposing them to outdoor conditions for about a week.

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

Direct sowing Lemon Balm is a simple and effective way to get it growing in your Midwest garden. You can sow seeds directly into the ground from mid April through late July. This method is less work than starting indoors, but your plants will take a little longer to mature.

Make sure the soil is well-drained and the soil temperature is consistently above 60°F. Sow seeds about ¼ inch deep and space them 18-24 inches apart. Keep the soil moist until the seedlings emerge.

Lemon Balm appreciates consistent moisture, but it's not a fan of soggy soil, which is something to keep in mind with our wet summers here in the Midwest. During the spring, when temperatures are cooler and rainfall is more frequent, you might only need to water once a week, if at all. Let the rain do its job.

As we move into summer and experience those moderate-to-hot days, increase your watering frequency to 1-2 times per week, depending on rainfall. The "finger test" is a reliable way to check if your plants need water: stick your finger about two inches into the soil. If it feels dry, it's time to water. Aim for about 1 inch of water per week, either from rainfall or irrigation.

Water at the base of the plant to avoid wetting the foliage, which can increase the risk of fungal diseases in our moderate-to-humid climate. Signs of underwatering include wilting or yellowing leaves, while overwatering can lead to root rot. A layer of mulch, like straw or shredded bark, can help retain moisture and regulate soil temperature, which is especially helpful during those summer heat spells.

Lemon Balm is a pretty low-maintenance plant, but a little pruning goes a long way. In midsummer, when the plant is at its peak, cut it back by about half to prevent it from getting too leggy and to encourage new growth.

Be sure to remove any flower stalks as they appear, unless you want it to spread aggressively. Lemon Balm is known for self-seeding, and it can quickly take over your garden if you let it. As we approach the first frost around mid- October, you can give your Lemon Balm a final trim, but leave some foliage for the winter.

You can start harvesting Lemon Balm leaves as soon as the plant is established, usually around late June. The best flavor is before the plant starts to flower, so keep an eye out for those flower stalks and harvest before they open. You can continue harvesting throughout the summer and into late October.

To harvest, simply snip off the leaves with scissors or pruning shears. Avoid taking more than one-third of the plant at a time to ensure continued production. Lemon Balm is best used fresh, as it tends to lose its flavor when dried, but you can still dry or freeze it if you have a surplus. As the first frost approaches, harvest as much as you can and preserve it for winter use.

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

Aggressive Spreading

• What it looks like: Lemon Balm popping up in unexpected places throughout your garden.
• What causes it: Self-seeding and underground runners allow it to spread quickly.
• How to fix/prevent it: Remove flower stalks before they go to seed. Plant it in a container, or create a physical barrier in the ground to contain the roots.

Bolting

• What it looks like: The plant sends up a flower stalk prematurely, and the leaves become bitter and tough.
• What causes it: Triggered by heat, long days, or drought stress.
• 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 leaves regularly to encourage continued leaf production.

Powdery Mildew

• What it looks like: A white or grayish powdery coating on the 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 as needed. Remove affected leaves. Apply neem oil or potassium bicarbonate sprays.

Midwest Specific Challenges: Our moderate-to-hot summers and moderate-to-humid conditions can create an ideal environment for powdery mildew. Be sure to provide adequate spacing and air circulation to prevent this fungal disease. Additionally, keep an eye on moisture levels, as Lemon Balm prefers consistent moisture but doesn't like to be waterlogged, which can be a tricky balance with our wet-summer rainfall.

Lemon Balm is a great companion plant for several vegetables in the Midwest garden.

• Tomatoes: Lemon Balm repels tomato hornworms and other pests that can damage tomato plants.
• Squash: It attracts pollinators, which are essential for squash production.
• Broccoli and Cauliflower: Lemon Balm can help deter cabbage moths, which are a common pest of these brassicas.

Avoid planting Lemon Balm near rue or other members of the mint family, as they can compete for resources and attract similar pests.