Leaf lettuce 'Black Seeded Simpson'

Sun

Full sun in cool weather; afternoon shade helps extend harvesting as temperatures rise.

Water

Keep the root zone evenly moist but not waterlogged. Shallow roots dry quickly, especially in containers.

Soil

Fertile, moisture-retentive but well-drained soil, ideally with a pH of 6.0-7.0.

Height

0.5-1 ft (0.15-0.3 m) in leaf; flowering stems can reach 2-3 ft (0.6-0.9 m)

Spread

0.75-1 ft (0.23-0.3 m)

Foliage

Broad, tender, light green leaves with crinkled surfaces and frilled edges, forming an open rosette rather than a firm head.

Growth

Fast; usually ready for full-sized leaf harvest about 40-50 days after sowing in suitable conditions.

Care needed

Medium

• Low allergen
• Edible

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Needs looking after

Pick your zone, country, light and whether you have pets.

1. Planting day

   0.5 ft (0.15 m)

2. After 1 year

   0.7 ft (0.22 m)

   full size

Full size in one season.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Growth rate

Fast

• Water at soil level whenever the surface begins to dry; avoid repeated drying out.
• Mix mature compost into the bed before sowing. Feed container plants lightly with a balanced liquid fertilizer if growth slows.
• Thin plants to 8-12 inches (20-30 cm) apart for full-sized rosettes.
• Apply a thin layer of clean mulch around established plants, keeping it clear of the central growing point.
• Provide afternoon shade during warm spells, but replace plants once they bolt or become bitter.

Pruning. No routine pruning is needed. Remove damaged outer leaves promptly, and keep the central growing point intact when harvesting individual leaves.

Pick baby leaves once they are about 3-4 inches (8-10 cm) long, often around 25-30 days after sowing, or harvest full-sized leaves at about 40-50 days. Take the outer leaves first, leaving the centre to grow, or cut the whole rosette at soil level. Harvest before a tall central flower stalk develops, when leaves usually become tougher and bitter.

Late winter

In mild climates, sow under cover for an early crop; in cold climates, wait until spring approaches.

Early spring

Sow shallowly outdoors once soil is workable, or plant hardened-off seedlings; protect from hard freezes.

Spring

Thin seedlings and sow a short row every two to three weeks while conditions remain cool.

Late spring

Harvest outer leaves regularly and keep the soil evenly moist.

Summer

Provide afternoon shade in warm areas; pause sowing during persistent heat if germination and leaf quality decline.

Late summer

Resume sowing as temperatures fall, allowing roughly six to eight weeks before regular hard freezes.

Autumn

Harvest remaining leaves and use fleece or a cold frame to protect crops from light frosts.

• Edge vegetable beds with low rows of frilled, light green foliage.
• Alternate with red-leaf lettuce for contrasting bands in a potager.
• Grow in patio containers or window boxes with drainage holes for convenient harvesting.
• Use as a short-season filler between young brassicas before they need their full spacing.

Garden styles it suits: Potager (kitchen garden), Edible landscape, Cottage garden, Homestead, Small-space and Family-friendly.

Plant it with: Radishes, Carrots, Spring onions, Beetroot, Calendula and Red-leaf lettuce.

Wildlife: Leaves attract slugs, snails, rabbits and deer. Plants allowed to flower may provide food for small visiting insects, but harvesting normally takes place before flowering.

• Slugs and snails: protect young plants with barriers, remove hiding places and hand-pick after dark; use an approved iron phosphate bait if needed.
• Aphids: inspect leaf folds and undersides, rinse colonies off with water and remove heavily infested leaves.
• Downy mildew: allow airflow, water at soil level and remove affected plants; avoid repeatedly growing lettuce in the same spot.
• Bolting and bitter leaves: sow during cool seasons, prevent drought stress and provide afternoon shade; replace plants once flower stalks develop.

Cultivated lettuce is not known to be toxic to people, cats, dogs or horses. The leaves are edible; it is not a substitute for a balanced animal diet, and large amounts may cause digestive upset.

• Leaf lettuce 'Grand Rapids' (Lactuca sativa 'Grand Rapids')

  Another green, frilled loose-leaf lettuce, often with more upright growth. The cultivars can be difficult to distinguish reliably by appearance alone; use labelled seed.

• Butterhead lettuce (Lactuca sativa (Butterhead Group))

  Usually has smoother, rounder leaves that overlap into a soft head, unlike the open, frilled rosette of 'Black Seeded Simpson'.

Lactuca comes from the Latin word for milk, referring to the milky sap, while 'Black Seeded' describes the cultivar's dark seeds.

Propagation. Grow from seed, sown about 1/8 inch (3 mm) deep in moist soil or seed compost. Germination is best in cool conditions and can be poor in hot soil; start seedlings somewhere cooler for warm-season planting.

Accepted botanical name

Lactuca sativa

In the US and Canada

Introduced in the lower 48 states, Pacific Basin, Puerto Rico and US Virgin Islands.

Native range

Iraq.

Measured

Average height 42 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.