Widely used in oriental cooking for the swollen base of its edible stems, lemon grass makes a fountain of gently arching foliage that can eventually reach 1.5m (5ft). Due to its tropical origins, this herb cannot stand frost, so should be grown in a container allowing it to be moved indoors after spending summer outdoors in a sunny position.
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Start seeds in small pots in spring. Sow thinly on the surface, pressing them down gently to ensure they are in good contact with the compost and water from beneath by placing the pot in a saucer of water. Germinate in a heated propagator.
When seedlings are large enough to handle, arrange three in a small pot filled with multi-purpose compost and place on a bright, frost free windowsill.
When roots show through the bottom move into a larger pot – it may be necessary to do this several times, plants eventually ending up in a 20cm (8in) pot, before the lemongrass is ready to be placed in a sunny spot outside in early summer.
Place plants in a sunny, sheltered position over summer and keep well watered.
Move plants back indoors in late summer, putting it in a bright, cool position and reduce watering, keeping the compost just moist. A minimum temperature of 5C (40F) is ideal.
When foliage starts to turn brown in autumn, cut back foliage to 10cm (4in).
As new growth appears in spring, feed plants weekly with a balanced liquid fertiliser.
Plants can also be raised from stems bought in shops. In spring or summer, place lengths of stem into small pots, put in sunny position and water. Roots should appear quickly from the base. When roots appear through the drainage holes at the bottom of pots move into a slightly larger container.
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.