Lettuce is one of the fastest crops — ready in 4-8 weeks. Resow every 2-3 weeks for continuous supply.
Varieties
| Variety | Days | Note |
|---|---|---|
| Head lettuce | 60-70 | Harvest in morning |
| Lollo Rosso | 50-60 | More heat-tolerant |
| Leaf lettuce | 30-40 | Continuously harvestable |
| Rocket/arugula | 25-35 | Peppery, very fast |
Sowing
- February to mid-October; resow every 2-3 weeks!
- Above 25-30°C head lettuce bolts — sow leaf lettuce only in July
🔗 Related articles
- Grey mould identification and organic control — common on lettuce in humid conditions
- Organic slug control — lettuce’s main pest
- Identifying mosaic virus — can also affect lettuce
- Why does head lettuce bolt above 25-30°C, while leaf lettuce doesn’t react the same way?
Head lettuce is genetically a cool-season plant that perceives high temperature as a stress signal, and responds by accelerating flower stalk formation to set seed as quickly as possible before the “dangerous” warm period ends — this is bolting. Leaf lettuce varieties come from less heat-sensitive breeding lines, making them more tolerant of summer heat and keeping them in a vegetative, leaf-producing state far longer before they start flowering.
- Why is it recommended to resow lettuce every 2-3 weeks instead of sowing a large batch all at once?
Lettuce has a short growth cycle (30-70 days depending on variety), so a single large sowing would mean all plants mature at the same time, producing an unmanageable quantity of simultaneously perishable crop in a short window. Staggered sowing every 2-3 weeks (“succession planting”) ensures there’s always a fresh batch maturing while the earlier sowing is being used, providing a continuous, manageable supply of fresh lettuce throughout the season.
- Why does evening watering specifically increase the risk of grey mould in lettuce?
Grey mould fungus (Botrytis cinerea) spores germinate most effectively on plant surfaces that stay damp for extended periods, and since lettuce’s loose, overlapping leaf rosette already dries slowly, evening watering keeps the foliage wet all night. Combined with the overnight temperature drop, this prolonged moisture creates an ideal microclimate for fungal infection, unlike morning watering, when daytime sun dries the leaves within hours.
- Why is the 25-30 cm thinning distance so important for head lettuce?
For head lettuce to form a proper head, the inner leaves need to grow in a tight, compact arrangement around each other, which is only possible if the root zone and canopy have enough space to develop fully without interference. In overly crowded conditions, neighbouring plants’ foliage meets too early, creating competition for light, and the plant either fails to form a closed head at all or produces only a loose, smaller head due to the restricted space.