Lactuca sativa var. longifolia

RHS Plant Profile

cos lettuce

Other common names

manchester lettuce, romaine lettuce

Annual Biennial

Cos and romaine type lettuces, usually forming tall heads of crisp green or sometimes red-tinted leaves, useful for salads. Plants can be up to 30cm high depending on the cultivar

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

0.1-0.5 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 1 year
Max Spread: 0.1-0.5 metres
Max Height: 0.1-0.5 metres

Growing Conditions

Chalk Clay Loam Sand

Moisture: Moist but well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: East–facing or South–facing
Exposure: Sheltered
Hardiness

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

H1A: under glass all year (>15C)
H1B: can be grown outside in the summer (10 - 15)
H1C: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20): H3

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Asteraceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Clump forming
Genus: Lactuca can be annuals, biennials, perennials or shrubs, with alternate leaves, milky white sap and daisy-like flowers in white, yellow or blue. The genus includes a wide range of wild plants, as well as species cultivated for their edible leaves (lettuce)
Name Status: Unresolved

How to Grow

Cultivation

Grow in full sun or afternoon shade on moisture-retentive, ideally neutral soil. Water when the soil is dry, ideally early in the morning. Sow a short row every fortnight to ensure continuity of cropping. Use cloches or biodegradable horticultural fleece to protect early and late crops. See lettuce cultivation for more information

Propagation

Propagate by seed. See sowing vegetable seeds

Suggested planting locations and garden types

Cottage and informal garden
Patio and container plants

Pruning

No pruning required

Pests

May be susceptible to slugs and snails

Diseases

May be susceptible to grey moulds; some resistance to downy mildews