Early September is the best time to sow salad plants for harvests between November and early May, such as land cress, mustard, chervil, claytonia and lettuce.

Caption: Winter salads crop between November and May

Grow them out of the worst of the weather under a protective covering, such as glass, polythene, fleece or insect-proof mesh. Although no extra heat is needed, without any protective covering harvests are small in winter and of lower quality.
One sowing gives many picks when you pinch or cut off larger leaves, rather than cutting across the top of plants to take all the leaves in one go. Because of their long life of cropping, space plants at 20cm apart. Multi-sown modules work well to give more leaves of medium size.
The harvests of winter salads aren’t as big as for summer ones, but the flavours tend to be stronger. If you prefer something mild in winter, try claytonia or corn salad. Harvests from November until April vary according to the weather; in low temperatures you can get periods of almost nothing, while March to April sees relative abundance from the same plants. Many of the plants finish by flowering, mostly in late April, and their blooms are also edible and tasty. It’s best to use salads that are suited to winter growing, as they’ll both survive and make new leaves in the cool, damp conditions.

When to sow
Sowing at the right time helps plants to be large enough to withstand frost and slugs. It's best to grow plants under cover, such as glass, polythene, or fleece, without any extra heat, as it gives much better harvests. They're then planted outdoors when large enough to handle. For this way of growing sow by 20 September. If you’d prefer to grow outdoors without a protective covering, sow by 5 September. Before sowing, put on a 3cm-deep layer of compost on your beds to cover the ground.

Caption: It's best to sow indoors and plant out when large enough to handle

How to care for your plants
If you plan to cover your plants, use fleece only if the site is sheltered from wind or it may rip. Insect-proof mesh is easy to use, held up in a low curve by wire hoops. Alternatively a cloche, polytunnel or cold greenhouse all make great places to grow them. 

Caption: Insect-proof mesh is a tougher cover than fleece

The plants shouldn’t need watering and there are fewer pests around in winter than in summer. Little grey slugs can be a pain, though, making small holes in mostly the older leaves. When picking, always have a bucket to take damaged leaves, plus any slugs and weed seedlings you find, so that after picking the plants are beautifully clean, and with less slug habitat. Slugs’ main interest is older, decaying leaves.
Land cress grows well in cold conditions but it’s a favourite of pigeons – more than other brassicas such as mustards. Rabbits love winter salads, too, and netting held up by cloche hoops is an effective barrier against both of these.
When you harvest, just take the outer leaves, so the plant can carry on growing and produce further pickings. When the plants finally go to flower (bolt) in spring, it’s time to pull them up along with any weeds. It may be worth spreading an extra 2cm of compost on top of the existing mulch, unless there is plenty still visible on the surface from the dressing you made in September. Next plantings can be almost any vegetables, including courgettes, summer beans and potatoes.