Why Hardy Salads Earn Their Place

By the time September arrives, the summer lettuce has usually bolted, the slugs have had their fill and the vegetable patch looks a little sorry for itself. Yet this is precisely the moment to sow again. British winters are mild enough, on the whole, to keep a steady supply of leaves coming from the plot right through to March, provided you choose the right varieties and give them a little shelter when the weather turns.

The trick is to stop thinking of salad as a summer crop. Hardy winter leaves are built for short days and cold soils. They germinate in cooler temperatures, shrug off a light frost and, crucially, they do not bolt at the first hint of a grey afternoon. Sow them now and you will be cutting fresh mizuna for a Boxing Day sandwich while the rest of the garden sleeps.

The Reliable Trio: Winter Lettuce, Land Cress and Mizuna

Three crops do the heavy lifting in a cool-weather salad bed, and between them they cover crisp, peppery and tangy flavours.

• Winter lettuce. Look for hardy butterhead and cos types rather than the frilly summer varieties. 'Winter Density' is a stalwart, forming tight little hearts that stand through hard frost. 'Arctic King' and 'Valdor' are equally dependable. Sow them in modules and plant out while the soil is still warm, giving each plant 25–30cm so air can move between the leaves.
• Land cress. Also sold as American cress, this is the closest thing to watercress you can grow in open ground. It has a sharp, peppery bite, germinates in seven to fourteen days and keeps producing for months if you pick outer leaves only. Space plants about 15cm apart and keep the soil consistently damp.
• Mizuna. A Japanese mustard green with deeply serrated leaves and a gentle, warming heat. It is quick — often up within four to seven days — and forgiving of poor light. 'Tokyo Beau' is a good green-leaved strain, while the red types add a welcome flush of colour to winter plates.

If you have room, add corn salad (lamb's lettuce) and claytonia to the mix. Both are hardy, low-growing and happy to be tucked in at the front of a border.

Sowing Timing and Getting the Bed Right

The single biggest mistake is sowing too late. Winter salads need to reach a decent size before growth stalls, so aim to have them in the ground by mid-September in most parts of the UK, and by the end of the month in the milder south west. Further north, or on heavy clay, sow under cover a fortnight earlier.

Prepare the bed a week in advance. Fork it over, remove any large stones and work in a couple of buckets of well-rotted compost per square metre. Winter salads are not hungry crops, but they do need a soil that drains. Waterlogged roots in January will rot far faster than frozen ones.

Because germination can be patchy in cooling soil, I sow most of these into modules or seed trays in a cold frame and transplant the strongest seedlings. This wastes less seed, avoids the seedlings being washed out by autumn rain and lets you see exactly what you have. Firm the transplants in well and water them once, then leave them be.

Cloches, Fleece and the Art of Stretching the Season

Protection is what turns a modest autumn crop into a genuine winter harvest. A few degrees of warmth and a reduction in wind chill make an enormous difference to how much a plant grows between November and February.

• Fleece. Horticultural fleece of around 17gsm will see most hardy salads through several degrees of frost. Lay it loosely over hoops so it does not touch the leaves, and weight the edges with soil or bricks. On mild, still days, lift it to let air circulate — damp, stagnant air under cover invites botrytis.
• Cloches. Glass or rigid plastic cloches give more protection and last for years. A traditional barn cloche over a row of winter lettuce is a lovely thing, and the soil beneath it stays workable. Lift the ends for ventilation whenever the temperature climbs above about 8°C.
• Double up. In cold snaps, a layer of fleece inside a cloche can buy you another two or three degrees. Just remember to remove the inner layer once the weather eases.

A polytunnel or unheated greenhouse makes all of this easier, but it is not essential. A sheltered south-facing wall, a raised bed against a fence, or even a few pots on a windowsill will all do the job.

Watering, Pests and Winter Care

Resist the urge to water generously through winter. Damp soil plus cold roots is a recipe for rot. Water only when the soil is genuinely dry, and then do it in the morning so the surface has dried by nightfall. Under cover, plants may need a little more, so check with a finger pushed into the compost.

Slugs remain active in all but the hardest weather. Trap them under upturned grapefruit skins or a plank of wood, and clear fallen leaves where they hide. Pigeons will strip a row of young leaves in an afternoon, so net anything unprotected. Aphids can build up quietly under fleece, so inspect the undersides of leaves every week or two.

Cutting and Keeping the Supply Going

Harvest little and often. For mizuna and land cress, snip the outer leaves about 2cm above the base and the plant will keep pushing out new growth. Lettuce can be cut as a whole head or picked leaf by leaf — the loose-leaf types are more generous if you take just what you need for a single meal.

Growth will slow to a crawl in the darkest weeks of December and January, so do not expect miracles. What you will get, though, is fresh, tender, peppery leaves when everything else in the garden is dormant. Sow a short row every three weeks through autumn and you will have a succession rather than a glut — and by late February, with the light returning, your overwintered plants will surge away again just as the new season's sowing begins.