Lemon Balm

Lemon balm is an easy to grow, bushy, low-maintenance perennial herb. It has lemon-scented leaves that give a lemony touch to salads, sauces, fish dishes and herb teas. It is also great to use in potpourri!

Sowing 

Lemon balm is easy to grow from seed but some varieties may only be available to buy as a plant. Sow late winter to late spring. Fill a pot or tray with peat-free seed compost, water it and then thinly sow the seeds on top. The seeds are small so try your best at spacing them out and thin later if necessary. Cover the seeds lightly with compost or vermiculite and water again carefully. Putting a plastic dome or cling film on top can help germination but make sure it has air holes for ventilation. Keep the soil evenly moist until the seeds germinate – if they dry out they will most likely not germinate at all. Having said that, be careful not to overwater!

Lemon balm will ideally need 15-20°C to germinate well and should appear within 3 weeks. Once the seedlings appear, remove from the plastic and place in a bright location to grow on.

Plant care 

There’s no need to thin the seedlings out unless the pot is very crowded, but when they are about 5cm high, transplant each seedling into 15-20cm pots using peat-free multi-purpose compost. Grow them on in cooler conditions.  

You can keep the pot in your Harvst Mini Greenhouse or put it outside in early summer after the last frost. To acclimatise the plants to outdoor conditions, lift them outside in a sheltered, lightly shaded spot during the day, and put them back in at night. Gradually increase the time outside – do this for about two weeks before leaving them out all the time. Try to keep the pots well watered, but if possible – water in the morning so that the leaves can dry up during the day to avoid fungal disease. 

Lemon balm can quickly become invasive in the garden by spreading seeds. Therefore, remove the flowers off the plant as soon as they appear so as not to miss the boat before they go to seed! 

Lemon balms are perennial plants that die back in winter and regrow in spring so do not throw them away when they look dead in the winter. Pot grown lemon balm will need dividing every couple of years. Simply lift and divide the crowded plant and repot into individual pots.

Harvesting 

Like most herbs, Lemon balm is best used fresh so harvest as required, preferably in the morning. You can start harvesting as soon as leaves appear in spring and continue through to the first frosts. 

Watch out! 

Lemon balm is generally problem free but powdery mildew, which appears as a white powdery deposit on the leaves, can happen. It’s best avoided by keeping the soil moist and growing in cooler conditions.

Pro Tip

Keep an eye on the flowers and cut them off as soon as they appear. Not only will they make the plant invasive if going to seed, the leaves will also lose their taste if you let it flower! 

Nerdy facts

The botanical name of Lemon balm is Melissa officinalis and it is said to aid in digestive ailments such as bloating, colic, indigestions and nausea.