Lemon basil

Lemon basil: how do you recognise it?

Habit

Annual, bushy herbaceous plant about 40 cm tall and 30 cm wide, with square stems.

Leaves

Narrow, light green and pointed, smaller than those of sweet basil (about 3–5 cm); in opposite pairs.

Flowers

Small white flowers in long spikes, from July to September; they attract bees.

Scent and flavour

Clearly lemony, fresh and sweet; much milder than lemongrass but far more fragrant than sweet basil.

Roots

Fibrous and shallow; in a pot it needs a pot at least 20 cm wide.

Flowering: July–September · Harvest and fruit: June–September · Sowing: March–May · Plants: May–June · Pruning: June–August

Why grow it?

• A fresh lemon flavour that ordinary basil lacks: lovely with fish, chicken, salads, rice and desserts.
• Strongly scented leaves, and attractive as an ornamental in a pot on the terrace.
• Quick to grow from seed: within a few months you have a full plant.
• The white flower spikes attract bees if you let them bloom.
• Suits a pot on the windowsill, the vegetable garden or a greenhouse.

Lemon basil: where does it grow best?

• Full sun and warmth: a sheltered, sunny spot in the garden, a greenhouse or a warm terrace.
• Humus-rich, loose, free-draining soil; sand or loam, acid to chalky.
• Moderately moist: do not let the soil dry out, but do not keep it soggy.
• Sheltered from wind and cold nights; below 10 °C the leaves turn black and below 5 °C the plant dies.
• Space plants 20–25 cm apart; in a 20–25 cm pot, one plant per pot.

Light

Sun

Soil type

Sand or loam

Acidity

Not fussy

Moisture

Normal

Size

0.4 m tall, 0.3 m wide

Hardiness

Frost tender: overwinter indoors (above 5 °C)

Goes well with

• Tomato: Suits the same warm, sunny spot, and goes together in dishes.
• Parsley: Another culinary herb for the same container.
• French marigold: Colourful flowers that attract bees and hoverflies in a pot or vegetable garden.

Lemon basil: when and how to plant it?

Plant in May–June.

1. Sow in March–May indoors at 20–25 °C, the seeds only lightly covered (3 mm) on moist seed compost. They come up in 5–10 days.
2. Prick out the seedlings when they have two true leaves and put them in small pots in a bright, warm place.
3. In May get them used to the outdoors gradually and put them outside only after mid-May (after the Ice Saints), when nights are warmer than 10 °C.
4. Plant them 20–25 cm apart, at the same depth as in the pot, in humus-rich soil.
5. Water in generously straight away and spread a thin layer of mulch around the plant.

Care

Water

Regularly, in the morning at the base; keep the soil lightly moist but not wet. Do not water over the leaves: that encourages fungus.

Feeding

Sparingly: a little organic liquid feed every 2–3 weeks is enough. Too much fertiliser gives soft leaves with less flavour.

Pinching out

Pinch out the tips regularly, above a few leaves: this gives a bushy plant and new leaves.

Flower buds

Pinch out flower buds as soon as you see them, so the plant keeps making leaves instead of going to seed.

Harvesting

Pick the tips of young shoots; never take more than a third of the plant at once.

Tip: Pinch out the tips and flower buds regularly: that keeps it bushy and gives leaves for months. Sow indoors and put it outside only when the nights are warm.

Lemon basil: when to prune it?

Pruning months: June–August.

When: From June to August pinch or snip out the tips regularly, as soon as the plant is 15–20 cm tall.

How:

• Pinch out the tip of each shoot, just above a pair of leaves.
• Remove flower buds as soon as they appear: the leaves then stay more tender and tasty.
• Never harvest more than a third of the plant at once; always leave enough foliage.
• Towards the end of the season, let a few tips flower for the bees.

Caution: It is an annual: it dies at the first frost. Harvest everything before the first night frost.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

March–May indoors at 20–25 °C, only lightly covered. This is the usual method; choose a warm, bright place and keep the compost moist.

Cuttings

In August–September cut a tip of 8–10 cm, remove the lower leaves and stand it in a glass of water; roots form in 1–2 weeks. Then pot up for the windowsill.

Lemon basil: how does it get through the winter?

Hardy to 5 °C: protect in harsh winters.

• Not hardy: it dies at the first frost and turns black below about 5–10 °C. Here it is an annual.
• In September harvest everything before the first night frost and use or preserve the leaves.
• Put a few cuttings or a potted plant on a warm, bright windowsill to keep harvesting for longer; the plant grows more slowly there in the short days.
• Keep seed from a healthy plant in a dry, cool place for the next sowing.

Diseases and pests

• Downy mildew: Yellow patches on the leaves and a grey-purple fuzz underneath, especially in damp summers. Water at the base, space plants widely and remove affected plants.
• Damping off: Young seedlings collapse. Use clean seed compost, do not overwater and ventilate.
• Slugs: Holes in young leaves or bare stems. Pick them off, put a barrier round the plant or grow it in a pot.
• Black leaves: Cold damage below 10 °C. Bring plants indoors or cover them on cold nights; only put them out when it stays warm.

Through the year

• March: Sow indoors at 20–25 °C.
• April: Sow and prick out. Keep somewhere bright and warm.
• May: Last sowing indoors. After mid-May, harden off gradually and plant out.
• June: Plant out. Pinch out tips and start harvesting.
• July: Harvest. Pinch out flower buds. Water.
• August: Harvest. Let some flower for the bees. Take cuttings.
• September: Last harvest. Pot up cuttings for the windowsill.
• October: Harvest everything before the first frost. Clear away.

Edible and useful

Leaves (June–September)

Cut the leafy tips from June to September, always above a pair of leaves; pinch out the flower buds. Lemon basil smells and tastes fresh, of lemon and basil: lovely on tomatoes, in salads, with fish and prawns, in Thai and Indonesian dishes and in lemonade.

Storing

Fresh, it keeps for a few days with the stems in a glass of water on the worktop; not in the fridge, where the leaves turn black. Dried, little flavour remains: make pesto instead, or freeze the chopped leaves in olive oil.

Caution: As a kitchen herb, lemon basil is safe. It is not hardy: put it outside only after mid-May, in a warm, sunny spot, or grow it in a pot on the windowsill.

Eating and using is at your own risk: see the terms of use.

Recipes

• Tomato salad with lemon basil (Dish · 4 people · 15 min)

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• Lemon basil is a natural hybrid of sweet basil (Ocimum basilicum) and American basil (Ocimum americanum).
• In Indonesia it is called kemangi and is eaten raw with grilled fish and spicy sambal.
• The lemon scent comes from citral, the same substance found in lemongrass and lemon peel.