The lemon-scented leaves of this bushy perennial will create a pleasant fragrance in your polytunnel. This plant is also a useful herb that can be used fresh or dried to make herbal teas or used to give a lemony-intensity to salads, sauces and a range of fish recipes. The leaves are best used fresh as a garnish rather than cooked. Dried leaves are also used in potpourris or drawer fresheners.
Lemon balm is usually bought as a ready-grown plant in the spring, though some cultivars can also be grown from seed. Seeds should be sown between March and May, into trays of compost, and covered with a thin layer of compost. They should then be placed into a propagator at a good and consistent temperature. Be aware that the seeds can take up to three weeks to germinate.
Plant your plants purchased online, from a garden centre or plant nursery, and plants you have grown from seed, into their own pots or containers as soon as they are large enough to handle, and into their final growing positions as soon as the weather has warmed sufficiently where you live and all danger of frost has passed.
Lemon balm will do well in any well-drained soil and will grow happily in sun or partial shade. They can be grown in a bed or border in your polytunnel or outside, or in a pot or container. For one lemon balm plant, a 20cm pot will be the perfect size. Water in your plants well and make sure that the plant is always well-watered throughout the summer months.
After flowering, it is a good idea to cut back your plants to encourage a new flush of leafy growth. Cutting back in early summer will also encourage ornamental, variegated varieties to put forth strongly-coloured growth.
You can rejuvenate congested clumps of lemon balm by lifting and dividing your plants in the autumn months.
A polytunnel will aid lemon balm as inside a polytunnel they will not suffer from the excessive winter wet when can cause the roots to sit in waterlogged conditions and reduce the likelihood of rot setting in. In a polytunnel, lemon balm should be able to survive over the winter months and return to growth in the spring.
Lemon balm should be harvested between July and September and used fresh as required, or dried for later use throughout the year.
