How to Grow Red Lettuce
Red Lettuce At a Glance
Difficulty
Moderate
Category
Vegetable
Sun Exposure
Full Sun, Partial Sun
Frost Tolerance
Frost Hardy
Cold Hardiness
Survives to -7°C
Plant Family
Asteraceae
Growing Season
Cool Season
Plant Lifecycle
Annual
How to Start It
★ Recommended for beginners
Lettuce handles light frost, so sow it from about 2 weeks before your last spring frost, and again in late summer for fall. Sprinkle the seeds thinly and cover them very lightly, no more than 0.5 cm, since they need some light to sprout. They come up in 2 to 7 days: thin the seedlings to about 15 cm apart (pull the extras so each has room, and eat them). Sow a short row every 2 weeks for salad all season.
Red lettuce grows just like green lettuce, and the more sun it gets, the deeper its red colour (in shade it stays greener). It loves cool weather: in summer heat the seeds will not sprout well and the plants bolt (rush to flower) and turn bitter. Loose-leaf types like Red Salad Bowl and Prizehead can be picked leaf by leaf for weeks.
When To Start
First chance to plant
30 Days Before Last Frost
Last chance to plant
30 Days Before First Frost
When should you plant Red Lettuce?
Your planting dates depend on your local climate. Sign up and add your location to unlock personalized dates.
Your Red Lettuce Planting Window
Start planting
May 15, 2026
Last chance
Sep 10, 2026
Your Red Lettuce Calendar
Set your location to turn these into exact dates and reminders.
Sow red lettuce outdoors now, then again every 2 weeks
2 weeks before your last frost· every year
Optional: start red lettuce indoors in small cells
6 weeks before your last frost· every year· optional
Pick the outer red lettuce leaves, the centre keeps growing
4 weeks after your last frost· every year· optional
Did you water your red lettuce seedlings today? Keep the top of the soil damp until they are up and growing.
About 1 days after you plant it
Time to thin the red lettuce seedlings: snip the extras at soil level so each one has room to grow.
About 17 days after you plant it
Your red lettuce is growing! Keep the soil evenly moist so the leaves stay tender.
About 20 days after you plant it
Your red lettuce is nearly ready! Cut the outer leaves first and let the centre keep growing.
About 34 days after you plant it
Picking time may be here: check your red lettuce.
About 40 days after you plant it
The Journey Ahead
Red Lettuce's Lifecycle
Seedling
Mature Plant
Seed Production
Step 2
Planting & Sprouting
Expect sprouts in 2–7 days
Growing Tips
- 1Give red lettuce full sun in spring and fall for the best colour, and afternoon shade in summer.
- 2Mix compost into the soil before sowing, since fast leaves need rich, loose soil.
- 3Water lightly and often so the soil never dries out, because thirsty lettuce turns bitter.
- 4Water with compost tea every 2 weeks to keep the leaves coming.
- 5Pick slugs off by hand at dusk, and wash aphids off with a spray of water.
- 6Sow summer crops in the shade of taller plants, such as tomatoes, to keep them cool.
Seedling Phase
Step 3
Growth & Maturity
~40
Days to Maturity
20 cm
Mature Height
25 cm
Mature Width
Pests to Watch For
Diseases to Watch For
Mature Plant
Step 4
Harvesting
Harvest Window
45 days
When to Pick
Cut outer leaves or harvest whole head
How to Harvest
- 1Start picking when the outer leaves are about 10 cm long, usually 4 to 6 weeks after sowing.
- 2Cut or snap off the outer leaves at the base and leave the centre to keep growing.
- 3Pick in the morning, when the leaves are cool and crisp.
- 4Pull the whole plant once it starts to stretch tall in the middle, because that is the sign it will soon turn bitter.
- 5Rinse the leaves in cold water, spin or pat them dry, and keep them in a bag in the fridge for up to a week.
Step 5
Saving Seeds
How to Save Seeds
Lettuce flowers pollinate themselves, so seeds grow true as long as the variety is not a hybrid (hybrid F1 seeds will not), and keeping varieties about 3 m apart is plenty. Let your best plant (not the first to bolt) grow tall and flower in summer. About 2 to 3 weeks after flowering, the heads turn fluffy and white like a small dandelion. Shake the heads into a paper bag every few days, since they ripen a few at a time, then pick out the bits of fluff. Store the seeds labelled in a cool, dark, dry place, where they keep about 3 years.
Seed Production
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