Lemon Balm in Zone 6B — Northeast

Lemon Balm is a fantastic addition to any Northeast garden. Its refreshing lemon-citrus flavor is wonderful in teas, salads, and even desserts. Plus, it's incredibly easy to grow, adding a touch of bright green to your garden from late spring well into fall, and the bees love it!

Our short growing season and occasional late frosts can be a challenge, but Lemon Balm is quite hardy and adaptable. With a growing season of about 183 days here, you'll have plenty of time to enjoy a bountiful harvest.

Starting Lemon Balm indoors is certainly an option, especially if you're eager to get a head start. Begin in late February through mid March, about six weeks before you plan to transplant outdoors. This gives the seedlings a good head start before our unpredictable spring weather hits.

Use seed trays or small pots filled with seed-starting mix. Keep them warm and provide plenty of light – a grow light works wonders. Water gently from the bottom to avoid damping off.

Keep in mind that our late springs mean you'll need to keep an eye on the weather forecast and be prepared to hold off transplanting if there's a risk of frost. Direct sowing often works just as well, so don't feel pressured to start indoors unless you really want that extra head start.

Transplant your Lemon Balm seedlings outdoors from mid April through mid May, once the risk of frost has passed. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the cooler temperatures and stronger sunlight.

Choose a spot with full sun to partial shade and space the plants 18-24 inches apart. Keep an eye on the weather forecast – a late frost can still happen, even in late April. Be ready to cover the seedlings if necessary.

Direct sowing Lemon Balm is a perfectly viable option in the Northeast. Wait until mid April through late July, when the soil has warmed up a bit. Lemon Balm seeds need a soil temperature around 70°F to germinate well.

Prepare the soil by loosening it and removing any rocks or debris. Sow the seeds shallowly and keep the soil consistently moist until they germinate. Once the seedlings emerge, thin them to 18-24 inches apart. Direct sowing might mean a slightly later harvest, but it's often less work than starting indoors.

Lemon Balm prefers moderate watering. It tolerates slightly more moisture than some other herbs, but it's definitely not a fan of soggy soil. The key is to find that sweet spot, especially given our Northeast climate with moderate heat and humidity.

During the spring, when rainfall is generally even, 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 an inch of water per week, either from rainfall or irrigation. Water at the base of the plant rather than overhead, especially with our moderate-to-humid conditions, to help prevent fungal diseases.

In the summer, when temperatures climb a bit higher, you might need to water more frequently, especially if we're experiencing a dry spell. Again, use the finger test to determine if watering is needed. Signs of underwatering include wilting leaves, while overwatering can lead to yellowing leaves and root rot. A layer of mulch around the base of the plants can help retain moisture and keep the soil cool.

As we move into fall, reduce watering frequency as temperatures cool down and rainfall increases. Always adjust your watering schedule based on the weather conditions and the specific needs of your plants.

Lemon Balm requires minimal pruning. The main goal is to keep it from getting too leggy and to prevent it from spreading aggressively.

In midsummer, cut the plant back by about half. This encourages bushier growth and prevents it from becoming too tall and spindly. Remove any flower stalks as soon as you see them. Lemon Balm is a prolific self-seeder, and removing the flowers prevents it from taking over your garden.

As the first frost approaches in mid- October, you can give the plant one final trim. This helps to tidy it up for the winter, although the plant will likely die back to the ground. Don't worry, it will come back strong in the spring!

You can expect your first Lemon Balm harvest in late June through late October, about 70 days after planting. The best time to harvest is before the plant starts to flower, as the leaves have the most intense flavor at this stage.

Harvest the leaves by snipping them off with scissors or pinching them off with your fingers. Avoid taking more than one-third of the plant at a time to allow it to continue growing and producing. Lemon Balm is best used fresh, as it tends to lose its flavor when dried.

To encourage continued production, harvest regularly throughout the growing season. As the first frost approaches in mid- October, harvest as many leaves as you can. You can use them fresh or make a batch of Lemon Balm tea to enjoy throughout the winter.

Lemon Balm, while generally easy to grow, can have its share of problems in the Northeast. Here are three common issues you might encounter:

Aggressive Spreading

• What it looks like: Lemon Balm popping up in unexpected places throughout your garden, often far from where you originally planted it.
• What causes it: Lemon Balm is a prolific self-seeder. It spreads quickly through its seeds and can also spread through its roots.
• How to fix/prevent it: The best way to prevent aggressive spreading is to remove flower stalks before they have a chance to set seed. You can also contain the plant by growing it in a pot or raised bed. Be diligent about pulling up any unwanted seedlings as soon as you see them.

Bolting

• What it looks like: The plant sends up a flower stalk prematurely, and the leaves become bitter or tough.
• What causes it: Bolting is often triggered by heat stress or drought. While our summers are moderate, dry spells can still happen.
• How to fix/prevent it: Keep the soil consistently moist, especially during hot weather. Provide some afternoon shade if possible. Remove flower stalks as soon as you see them 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: Powdery mildew is a fungal disease that thrives in warm days, cool nights, and moderate humidity – conditions we often experience in the Northeast.
• How to fix/prevent it: Improve air circulation by spacing plants properly and pruning if necessary. Remove affected leaves promptly. You can also try spraying with neem oil or a milk spray (1 part milk to 9 parts water).

Northeast Specific Challenges: Our moderate heat and moderate-to-humid conditions can create a favorable environment for powdery mildew. Be vigilant about monitoring your plants and taking action at the first sign of trouble.

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

Good companions:

• Tomatoes: Lemon Balm repels tomato hornworms and other pests that can damage tomato plants.
• Squash: The strong scent of Lemon Balm can deter squash bugs and vine borers.
• Broccoli and Cauliflower: Lemon Balm can help repel cabbage moths and other pests that target brassicas.

I don't recommend planting Lemon Balm near anything you want to keep contained, as it spreads aggressively.