Cos Lettuce
Lactuca sativa var. longifolia
Cos lettuce is a dependable cool-season crop that produces crisp leaves and upright heads in mild subtropical weather. Regular planting and steady moisture can provide fresh harvests across much of autumn and winter.
Overview
At a Glance
Peak Planting Window
April to September
Seasonal Role
Cool-season succession crop
Difficulty
Very Easy
Planting Method
Direct sow or transplant
First Harvest
6–10 weeks
Sun
Full sun to part shade
Water
High
Heat Tolerance
Low
Humidity Tolerance
Moderate (good airflow recommended)
Family
Asteraceae
Category
Vegetable
Planting Calendar
Monthly Planting Guide
Month-by-month suitability for coastal subtropical Australia.
Rationale
Why This Planting Window
Cos lettuce performs best through the cooler months, when mild temperatures support steady leaf growth and reduce the risk of premature bolting. Autumn and winter plantings generally produce the crispest leaves and most reliable harvests in coastal subtropical conditions.
Reference
Growing Information
Lifecycle
Annual
Ideal Soil Temperature
10–22°C
Germination
4–10 days
Transplant Ready
3–4 weeks
Soil
Fertile, moisture-retentive, well-drained soil enriched with compost
Soil pH
6.0–7.0
Plant Spacing
25–30 cm
Row Spacing
30–40 cm
Frost Tolerance
Moderate
In the garden
Plant Care
Feeding
Prepare the soil with compost before planting and apply a light balanced feed during active growth. Avoid excessive feeding, which can encourage soft, weak leaves.
Watering Guidance
Keep the soil consistently moist, particularly during warm or windy weather. Irregular watering can cause bitterness, poor head formation and premature bolting.
Avoid Nearby
- No significant planting conflicts for home gardens.
Watch out for
Problems & Prevention
Common Pests
Aphids, slugs, snails, caterpillars and leaf miners.
Common Diseases
Downy mildew, bottom rot and bacterial leaf spot.
Common Mistakes
Allowing plants to dry out, planting in excessive heat, overcrowding, poor airflow and waiting too long to harvest mature heads.
Picking
Harvest
First Harvest
6–10 weeks
Harvest Window
Harvest whole heads at maturity or pick outer leaves regularly for an extended harvest
Harvest Indicators
Harvest when heads are firm, upright and well filled. For continuous picking, remove the outer leaves while leaving the central growing point intact.
Standard
SGGS Details
Subtropical Gardener Growing Standard — profile metadata.
- SGGS Code
- VEG002
- Version
- 1
- Confidence
- High
- Seasonal Role
- Cool-season succession crop
- Crop Champion Month
- June
Explore