Cut-and-Come-Again Lettuce on an Indoor Windowsill

Hearting lettuce indoors is a losing game — it wants more light than a window gives and takes ten weeks to get there. Loose-leaf lettuce cut young is the opposite: three weeks from sowing to the first cut, and three or four cuts from the same plants before you start again.

The setup

A tray 12–15 cm deep with drainage holes. Wider is better than deeper; lettuce roots are shallow.
Ordinary multi-purpose compost, levelled and firmed lightly.
A cool, bright spot. Lettuce is happier at 15–20 °C than in a hot bay window. Above about 25 °C it bolts.

Sowing

Scatter seed thinly across the surface — aim for a seed roughly every 2 cm — and cover with 5 mm of sieved compost. Water with a fine rose or a spray bottle so you do not wash the seed into corners.

Germination takes 5–10 days on a windowsill.

Varieties that work indoors

Loose-leaf varieties for indoor trays

Variety	Days to first cut	Cuts per sowing	Bolt resistance	Notes
Salad Bowl (green) Easiest	21–25	3–4	High	Forgiving of low light; mild flavour.
Lollo Rossa	25–30	3	Medium	Colour needs strong light or it stays green.
Oakleaf	24–28	3–4	High	Best texture of the four; slightly slower.
Little Gem	45+	1	Low	Hearts poorly indoors — grow it outside instead.

Timings are for a bright indoor windowsill at 18–20 °C. Sample data for demonstration — verify against your own sowings before publishing.

Cutting

When leaves are 8–10 cm tall, cut the whole patch with scissors about 3 cm above the compost. Leave the growing point intact and it regrows in 10–14 days.

By the fourth cut leaves get tougher and slightly bitter. That is the signal to tip the tray out, refresh the compost and start over.

Feeding and watering

Keep the compost evenly damp — not wet. A tray that dries out completely once will bolt or turn bitter, and it does not come back from that.

After the first cut, a half-strength balanced liquid feed every two weeks keeps the regrowth going.

Common problems

Long, pale, floppy seedlings — too little light, sown too thickly, or both. Thin them and move the tray.

Slimy patches at the base — damping off, caused by wet compost and still air. Water less, and crack a window for a few minutes a day.

Bitter leaves — heat or drought stress, or leaves left too long before cutting.

The rhythm that works

Sow a quarter tray every Sunday. From week four onwards there is always something ready to cut, and the whole thing takes about five minutes a week.