At a glance
- The secret to lettuce all summer is successional sowing: sow a small portion every two to three weeks instead of a whole bed at once.
- Loose-leaf and cutting lettuce crop for weeks, because you only pick the outer leaves and let the heart grow on. A head lettuce, by contrast, you harvest all at once.
- Lettuce germinates poorly in heat. Above about 22 to 25 degrees the seed takes a germination pause. Sow cool, in the evening or lightly shaded.
- Lettuce is a light germinator: only press the seed in, do not cover it with soil. Successional sowing runs from CW 12 to 34.
Almost every gardener knows the feeling: in June twenty lettuces head up at once, half of them bolt before you can eat them, and from July on there is nothing. Yet the answer is not more lettuce, but smarter timing.
Sow small batches two to three weeks apart instead of one big bed, and you harvest fresh heads evenly from spring into autumn. Combine that with loose-leaf lettuce that keeps regrowing, and you have practically never too much and never too little. That is exactly what we look at.
Head lettuce or loose-leaf?
The difference decides how you harvest. The head lettuce forms a firm head that you cut whole. Then the plant is gone and the space is free for the next batch.
The loose-leaf or cutting lettuce forms no firm head but a loose rosette. You only ever pick the outer leaves and leave the heart standing. New leaves grow from the heart, often over many weeks. For a continuous harvest it is the key.
Four types of lettuce for the bed
The right lettuce for every season
- Loose-leaf and cutting lettuce
Loose rosettes like oak-leaf or Lollo. Pick leaves again and again, leave the heart. The steady supplier. See the profile: oak-leaf lettuce.
- Head lettuce
The classic with a soft, closed head. Harvested whole, ideal for successional sowing. See the profile: head lettuce.
- Romaine and Batavia
Upright and crisp, more heat-tolerant and bolt-resistant than the tender head lettuce. The right choice for high summer.
- Lamb's lettuce for winter
The tough gap-filler for the cold season, sown from late summer on. See the profile: lamb's lettuce.
How to get successional sowing right
Sow little and often
Every two to three weeks, sow only as many plants as your family eats in that time. A short row or a few little pots is plenty.
Only press in, do not cover
Lettuce is a light germinator. Scatter the seeds thinly and only press them in, or sift the thinnest layer of soil over them. Sown too deep, it does not germinate at all.
Mix pre-growing and direct sowing
Pre-grow one part on the windowsill and plant it out as a sturdy seedling, sow another part direct. That way you bridge the moods of the weather.
Do not plant too deep
Set head lettuce so the heart stays above the soil. Sitting too deep, it rots easily at the base. Keep 25 to 30 cm spacing depending on the variety.
Keep picking loose-leaf lettuce
With loose-leaf lettuce, only ever take the outer leaves and leave the heart. That way you harvest from one plant again and again over weeks.
- Typ
- Annual leaf vegetable
- Familie
- Daisy family
- Standort
- Sun to part shade, some shade welcome in summer
- Aussaat
- Successional · CW 12 to 34
- Ernte
- May to October · CW 18 to 42
- Wasserbedarf
- Even, water in the morning
In high summer lettuce likes to strike at the germination stage already. The reason is a built-in safety catch: in heat above about 22 to 25 degrees the seed takes a germination pause, so it does not sprout into a drought.
Getting lettuce to germinate in high summer
On hot days, sow only in the evening when it cools, and keep the seedbed evenly moist and shaded. An even surer trick: put the moist seeds in the fridge for one to two days before sowing. The cold lifts the germination block.
Bolting in summer
Long days and heat make lettuce bolt: it pushes up a flower stalk and turns bitter. That is not a fault but its natural programme. For summer, choose expressly bolt-resistant varieties and, if in doubt, harvest a little earlier.
Not more lettuce, but a little more often. Small batches beat the one big bed.
The core rule for continuous lettuce
Frequently asked questions
Why does my lettuce bolt before I can harvest it?
The triggers are long days and heat, often together with drought stress. The lettuce switches to flowering and turns bitter. The remedies are bolt-resistant summer varieties, even watering and timely harvest.
Why does my summer sowing not germinate?
Because lettuce takes a germination pause in heat. Above about 25 degrees the seed just lies there. Sow in the evening, keep it cool and moist, or pre-soak the seeds in the fridge for one to two days first.
How exactly does loose-leaf lettuce work?
You only ever pick the outer, larger leaves and leave the inner ones and the heart. From there the plant regrows. That way you harvest a single plant over many weeks instead of cutting it whole.
Why does my lettuce taste bitter?
Bitterness comes from the start of bolting or from drought stress. Harvest young, water evenly and in the morning, and choose mild, bolt-resistant varieties in summer. After cutting, cold water helps make the leaves crisp.
Can I grow lettuce in winter too?
Yes, with the right kinds. Lamb's lettuce and winter purslane defy the frost, and under fleece you harvest almost all year. Chard too supplies leaves for the kitchen for a long time.
Sources
- Julius Kühn Institute: growing lettuce in the home and allotment garden
- German Federal Centre for Nutrition (BZfE): lettuce, growing and storage
- Related in the magazine: The garden in July and Sowing carrots without carrot fly
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