Lettuce planting months by climate zone
The chart comes from the same data as the planting calendar. Tap a zone for its full calendar and the towns it covers.
| Zone | J | F | M | A | M | J | J | A | S | O | N | D | Sow or plant |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tropical | yes | yes | yes | Apr–Jun | |||||||||
| Subtropical | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | All year |
| Arid and semi-arid | yes | yes | yes | yes | yes | yes | yes | yes | Mar–Oct | ||||
| Temperate | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | All year |
| Cool | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | Aug–May | ||
| NZ warm north | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | Aug–May | ||
| NZ temperate | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | Aug–May | ||
| NZ cool south | yes | yes | yes | yes | yes | yes | yes | yes | Sep–Apr |
sow or plantnot recommendedthis month
The gaps in the chart are the extremes. Cool-zone and New Zealand gardens skip the depth of winter. The arid zone skips the hottest months, and the tropics sow only in the milder dry season. Lettuce can be sown direct or planted as seedlings, and is ready to pick in about 6–12 weeks.
Soil temperature: fast when mild, stuck when hot
The classic germination table by J. F. Harrington of UC Davis, republished by Oregon State University Extension, shows how tolerant lettuce is of cold:
| Soil temperature | Days for seedlings to emerge |
|---|---|
| 0 °C | 49 |
| 5 °C | 15 |
| 10 °C | 7 |
| 15 °C | 4 |
| 20 °C | 3 |
| 25–30 °C | 2 |
| 35 °C | little or none |
Lettuce germinates, slowly, in soil only just above freezing, which is why it can be sown through most of the year. Heat is the problem. A 2015 paper in Plant Physiology found that seed of most lettuce varieties fails to germinate when it soaks up water at 29 °C or more, a response called thermoinhibition. The seed company Starke Ayres puts the point where germination starts to suffer at 25 °C. It explains it as a secondary dormancy, triggered when seed soaks up water at high temperature. The seed isn't dead; it comes up once conditions cool.
Growing lettuce through summer
- Sow cool. Starke Ayres puts the ideal at 15–20 °C. Its remedies for heat are to pre-water the soil, which cools as the water evaporates, and to sow early in the morning, when soil temperatures are lowest.
- Raise seedlings somewhere cooler. Use a shady spot or indoors, then plant them out on a mild day.
- Choose heat-tolerant varieties and give afternoon shade. Heat makes lettuce bolt, sending up a flower stalk and ending the harvest.
- Keep the water up. Mulch around the plants, and see the watering calculator for run times.
Sow little and often
A whole row sown at once is ready at once and bolts at once. Sow a short row, or a few seeds in a punnet, every few weeks, so a new batch is coming on as the last one is picked. Loose-leaf types can be picked leaf by leaf over several weeks, which stretches each sowing further.
- Spacing: 20–30 cm apart, as in the calendar. The plant spacing calculator works out how many fit in your bed.
- Pots: lettuce is one of the few crops that manages in a small pot. The pot size guide gives 4–11 litres of mix.
- Rotation: lettuce is in the daisy family, so it fits into a crop rotation wherever there is space.
Questions
When should I plant lettuce in Melbourne?
Melbourne is in the cool zone, where the calendar gives every month except June and July. Spring and autumn sowings are the easiest. In summer, sow early in the morning into freshly watered soil and give the plants afternoon shade.
Why won't my lettuce seeds germinate?
Usually because the soil is too hot. Germination suffers above about 25 °C, and most varieties fail at 29 °C or more. Water the soil first to cool it, sow early in the morning, or start the seeds somewhere cooler. In cold soil they are slow, not dead: about two weeks at 5 °C.
Can you grow lettuce in summer in Australia?
Yes in temperate and subtropical areas, with heat-tolerant varieties, afternoon shade, plenty of water and seed sown in the cool of the early morning. In the tropics and arid zone the calendar leaves summer out, because the heat stops germination and makes plants bolt.
How often should I sow lettuce?
A few seeds every few weeks. Lettuce is ready in about 6–12 weeks, so small, regular sowings give a steady supply instead of a glut that bolts all at once.
Sources
- Oregon State University Extension, Soil temperature conditions for vegetable seed germination, after J. F. Harrington, UC Davis – lettuce germination range and days to emergence.
- Yoong F.-Y. and colleagues (2015), Genetic variation for thermotolerance in lettuce seed germination, Plant Physiology – seed of most cultivars fails to germinate at 29 °C or greater.
- Starke Ayres, Lettuce and thermodormancy – optimum 15–20 °C, germination compromised above 25 °C, secondary dormancy, pre-watering, early-morning sowing, primed seed.
- Planting months, spacing and harvest time: the GardenMaths planting calendar, from ABC Gardening Australia, the NT Government, Tui and others listed on each zone page.
Last reviewed 24 September 2026 · Report an error