Winter Density
The variety that puts lettuce on the table in December and January, and the reason an August sowing is worth remembering.
Winter Density is a small dark green cos with the dense hearting habit of a butterhead, and it is genuinely hardy, which most lettuce is not. Sown in late August or early September and given a cloche, it sits through an Irish winter and gives you leaves in the months when the rest of the garden has stopped. It is equally good sown in spring for a summer crop, but it is the winter sowing that makes it worth a place in an Irish seed box. Arctic King and Valdor do a similar job if you cannot find it.
Quick facts
- Botanical name
- Lactuca sativa
- Type
- Open pollinated
- Category
- Cos, winter hardy
- Difficulty
- Easy, good first crop
- Hardiness
- Hardy, takes Irish frost
- In Ireland
- Cloche or fleece helps
- Germination
- 6 to 12 days at 10 to 20C
- Sowing depth
- 6mm
- Spacing
- 25cm apart, 30cm between rows
- Height
- 25cm
- Position
- Full sun
- Containers
- Grows well in pots
- Sowing to harvest
- 6 to 14 weeks
- Harvest
- All year
- Award
- RHS Award of Garden Merit
Sowing and harvest calendar for Winter Density
Months shaded below are the reliable windows for Irish conditions.
Where to buy Winter Density lettuce seeds in Ireland
Irish suppliers that stock this, so postage stays domestic and seed arrives in time to sow. These are plain links, not paid placements.
Order online
- Brown Envelope Seeds Irish Organic seed saved in West Cork, selected under Irish conditions Grows and saves its own certified organic seed in West Cork, so the varieties are already adapted to Irish conditions. Visit Brown Envelope Seeds , Co. Cork
- Quickcrop Irish Sowing and harvest months on every listing Ballymote based, lists sowing and harvest months per product and ships across Ireland. Visit Quickcrop , Co. Sligo
- Seedaholic Irish Heirloom and winter salad range, posted from Co. Galway Family run in Clonbur since 2005, deep heirloom range with detailed growing notes on every packet. Visit Seedaholic , Co. Galway
Why it suits Ireland
Nearly every crop on this site has a season that ends. Winter Density is one of the few that fills the gap, and in a climate where hard frost is the exception rather than the rule, an overwintered lettuce is far more realistic here than it is in most of continental Europe.
The limiting factor in an Irish winter is daylight, not cold. From November to February there are not enough hours to grow anything much, so the strategy is to grow the plant to a decent size before the light goes and then draw on it slowly. That is exactly what a late August sowing does.
The second Irish factor is rain. This variety is hardy enough for our winters but no lettuce is designed to sit in permanently wet leaf litter, so the cover is about keeping rain off rather than keeping frost out.
Growing notes
Sow in modules in late August, thin to one seedling, and plant out in late September or early October at 20 to 25cm apart. Wider spacing than summer lettuce is deliberate: air moving between the plants is what keeps botrytis out.
Clear every yellowing lower leaf through the winter, every couple of weeks. Left in place they rot into the crown and take the plant with them. Ventilate a tunnel or lift a cloche on any dry day, even in January.
Water sparingly from November to February and only in the morning. Overwintered lettuce needs far less than people expect, and a wet crown on a cold night is the main way these plants are lost.
Pick outer leaves through the winter rather than cutting heads. From late February let the plants run on and heart up, then cut whole in March or April. Anything still standing in May will bolt, so use it before it does.
Common questions
When exactly should I sow Winter Density for a winter crop?
Late August to the first week of September for most of Ireland, and you can push to mid-September on the south coast or if the plants are going into a polytunnel. The aim is a sturdy plant with six or eight true leaves by the end of October, because growth effectively stops in November when daylight drops. Sown too late it stays as a seedling all winter; sown too early in July it may bolt before winter arrives.
Does Winter Density need a polytunnel?
No, but it needs something. The plant itself will take frost, and that is not what kills it here. What kills it is weeks of rain sitting in the crown, which turns to grey mould. A cloche, a low tunnel of fleece over hoops, or even a sheet of clear corrugated plastic propped over the row will get it through. A polytunnel or greenhouse bed is easier and gives a bigger, cleaner crop.
How much will it actually grow over an Irish winter?
Very little between mid-November and mid-February, because it is short of light rather than warmth. Treat the plants as a standing store you draw on slowly rather than a crop that keeps producing, and take a few outer leaves from each rather than cutting whole heads. From late February the same plants put on a fast burst of growth and heart up properly in March and April.
Can I sow it in spring instead?
Yes, and it is a good spring lettuce in its own right. Sown from March it gives a compact dark cos in about eleven weeks, with better standing ability in a warm spell than a butterhead. It just does not have the same advantage over other varieties in summer that it has in December.
More lettuces to consider
Tom Thumb
Heirloom / Mini butterhead
The best lettuce for a container, a small plot or a first sowing with children, and it is ready faster than anything else.
Growing notes and stockistsWebb's Wonderful
Heirloom / Crisphead, iceberg type
The crunch of a shop bought iceberg with actual flavour, if you can give it space, water and a slug plan.
Growing notes and stockistsSalad Bowl
AGMOpen pollinated / Loose leaf, cut and come again
The most forgiving lettuce there is, and the one that turns a single sowing into six weeks of picking rather than ten days.
Growing notes and stockists