Lemon Balm in Zone 6A — Southeast

Lemon Balm is a fantastic herb to grow here in the Southeast. Its lemony flavor adds a bright note to teas and dishes, and it thrives in our long summer. Plus, there's something deeply satisfying about snipping fresh herbs straight from your garden, especially when the afternoon thunderstorms roll in.

Sure, we have our share of challenges with the hot and humid summers, clay soil, and pests. But with a little planning and attention to timing, you can easily grow Lemon Balm during our long, 198-day growing season.

Starting Lemon Balm indoors is an option, but honestly, with our long growing season, it's usually not essential. If you're eager to get a head start, though, you can start seeds indoors from mid-February through mid-March – about six weeks before you'd want to transplant them outside.

Use seed trays filled with a good seed-starting mix. Keep them warm and provide plenty of light, either from a sunny window or a grow light. Bottom watering is a great way to keep the seedlings evenly moist without encouraging fungal diseases, which can be a problem in our moderate spring climate.

Transplant your Lemon Balm seedlings outdoors from early April through early May, once the risk of frost has passed. Be sure to harden them off first by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind.

Space the plants 18-24 inches apart. Keep an eye on the weather forecast – those late-season cold snaps can still happen!

Direct sowing Lemon Balm is a super easy option in the Southeast. Sow the seeds directly into the garden from early April through early August. The soil needs to be warm enough for germination, but that's usually not a problem for us!

Prepare the soil by loosening it and removing any weeds. Sprinkle the seeds lightly on the surface and gently press them in. Keep the soil moist until they germinate, then thin the seedlings to 18-24 inches apart. Direct sowing is great because it avoids transplant shock, but it does mean the plants will mature a bit later.

Lemon Balm likes consistent moisture, but it doesn't want to be waterlogged. Here in the Southeast, with our hot and humid summers and afternoon thunderstorms, watering can be tricky. The key is to find the right balance.

During the spring and fall, when temperatures are milder, check the soil moisture regularly. Stick your finger about two inches deep into the soil – if it feels dry, it's time to water. Aim for about 1 inch of water per week, including rainfall.

In the heat of summer, you might need to water more frequently, especially if it hasn't rained. Water at the base of the plant rather than overhead, which can encourage fungal diseases in our humid climate. Signs of underwatering include wilting leaves, while overwatering can lead to yellowing leaves and root rot.

A good layer of mulch around your Lemon Balm plants helps retain moisture and suppress weeds. Pine straw or shredded hardwood mulch works well in our region, and also helps prevent soil splashing during heavy summer rains.

Lemon Balm is a pretty low-maintenance plant when it comes to pruning. The main thing is to keep it from getting too leggy and to prevent it from self-seeding, as it can be quite aggressive.

In midsummer, give your Lemon Balm a good haircut, cutting it back by about half. This encourages bushier growth and prevents it from getting too tall and spindly. You'll also want to remove any flower stalks as soon as you see them, unless you want a Lemon Balm jungle!

At the end of the season, as the first frost approaches in late October, you can cut back the plant to a few inches above the ground. It will come back strong in the spring.

You can start harvesting Lemon Balm leaves about 70 days after planting, typically around mid-June. Look for healthy, vibrant green leaves – these have the best flavor. The flavor is best before the plant starts to flower, so keep an eye out for flower stalks and remove them.

To harvest, simply snip off the stems with scissors or pruning shears. Don't take more than a third of the plant at any one time, to allow it to keep growing. Lemon Balm is best used fresh, as it loses a lot of its flavor when dried.

Keep harvesting throughout the summer and into the fall, until the first frost. Even after a light frost, you can often still harvest some usable leaves.

Lemon Balm is generally easy to grow, but here in the Southeast, we face a few common problems:

Aggressive Spreading

• What it looks like: Lemon Balm pops up everywhere in your garden, even where you didn't plant it.
• What causes it: It self-seeds readily and spreads through underground roots.
• How to fix/prevent it: Remove flower stalks before they go to seed. Consider growing it in a container to limit 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 our summer heat and sometimes drought stress.
• How to fix/prevent it: Plant in a spot that gets some afternoon shade. Keep the soil consistently moist. Remove flower stalks as soon as you see them.

Powdery Mildew

• What it looks like: A white or grayish powdery coating on the leaves.
• What causes it: Various fungi that thrive in warm days, cool nights, and moderate humidity – all common in the Southeast.
• How to fix/prevent it: Improve air circulation by spacing plants adequately and pruning. Remove affected leaves. Apply neem oil or potassium bicarbonate sprays.

Southeast Specific Challenges: Our hot and humid summers, combined with our wet-summer rainfall, create the perfect environment for fungal diseases like powdery mildew. Be sure to provide good air circulation and avoid overhead watering.

Lemon Balm makes a great companion plant for several vegetables in the Southeast garden.

• Tomato: Lemon Balm can help repel pests like whiteflies and tomato hornworms.
• Squash: It can deter squash bugs and vine borers.
• Broccoli and Cauliflower: The strong scent of Lemon Balm can confuse cabbage moths, protecting these brassicas from their larvae.

Avoid planting Lemon Balm near plants. It generally doesn't have bad companions, but its aggressive nature could take over a smaller, less vigorous plant.