Lemongrass is an ingredient used in a range of Asian recipes and is a wonderful addition to home growing for anyone who enjoys Thai or other East Asian cuisines. Lemongrass will need to be grown under cover and, likely, kept indoors in a humid, warm space over the winter months, but other than its requirement for heat, this is a plant that is actually relatively easy for the UK gardener to grow. While in most parts of the UK, your lemongrass will be able to be brought outside in the summer months, a polytunnel will give your plant that extra little bit of warmth and protection from the vagaries of the British weather. Since you will be moving your lemongrass around, it is best grown in containers in the UK.
Lemongrass can reach up to 1.5m tall with optimum growing conditions. You can either buy small lemongrass plants from a garden centre or plant nursery or you can grow your own from seed, starting in the early spring. Sow seeds thinly on the surface of the growing medium and firm them down – this is to make sure they are in good contact with the soil and water they will need to germinate. For the best germination rates it is a good idea to use a heated propagator.
You should then pot up the seedlings into their own containers and then move to larger pots again whenever roots show through the bottom of the pot they are in. Seedling should be kept on a bright, frost-free windowsill until it is warm enough to transfer them to the polytunnel or a sheltered spot outside in the early summer.
Lemongrass will grow well if well watered over the summer months and kept in a relatively humid atmosphere. As the end of the season draws near, however, reduce and then nearly stop watering all together – water just enough to keep the soil just moist. A minimum winter temperature of around 5 degrees Celsius over the winter is perfect. In some areas, this may be achievable in an unheated polytunnel, though most people may choose to bring their lemongrass inside in case of any unexpected frosts.
Lemongrass can simply be harvested by chopping off stems as required at any time. You should be able to harvest little but often throughout the whole year. Lemongrass imparts a citrus flavour but will take up a lot less space than a lemon tree or another citrus fruit tree. The leaves can also be harvested and used to a make a tea.