When to sow winter purslane

Winter purslane, also sold as claytonia or miner's lettuce, is a cold-season salad. Its seed only germinates when the soil is below about 54°F, and sprouts best around 39–54°F. Sown into warm summer soil, it simply sits there.

For winter salad, sow outdoors from late August to early October, once the nights have cooled. September is the safest month in both Central Europe and the UK. Under cover, in a cold frame, polytunnel or unheated greenhouse, you can keep sowing through to February.

A spring sowing in February or March (April in cool spots) works too, but the plants flower within a few weeks of warmer weather, so the harvest is short.

Winter purslane is not the same plant as summer purslane (Portulaca oleracea). That one has fleshy oval leaves and yellow flowers and wants warmth; winter purslane has round, stalked leaves and tiny white flowers and wants cold.

Choose a spot in sun or partial shade with moist, humus-rich soil that doesn't waterlog. The pH hardly matters. A bed just cleared of summer crops is ideal: winter purslane is a light feeder and gets by on what the previous crop left behind, so there's no need to fertilise.

Sow thinly in drills 0.2–0.4 in deep, only just covered, with rows 6–8 in apart. Keep the soil moist until the seedlings appear after 10 to 21 days. The first leaves are narrow and grass-like, so don't weed them out by mistake.

Thin the seedlings to 2–4 in apart once they have a couple of true leaves. You can also scatter the seed thinly in a strip and thin later, or sow a few seeds per module under cover and plant the clumps out 4 in apart after three to four weeks.

A 120 × 80 cm raised bed holds four to five rows of about 12 plants, roughly 50–60 in all. For most households a strip of two or three rows across one end of the bed is plenty; the rest can go to lamb's lettuce or winter lettuce.

Winter purslane is one of the hardiest salad crops. It gets through normal Central European and UK winters outdoors without protection. In hard frost the leaves turn reddish and a little tough, then recover when it turns milder.

Cover it with fleece, a cloche or a cold frame anyway if you can. The plants keep growing in mild spells, the leaves stay more tender, and you pick more. In very cold, snowless frost, cover is also the safer bet.

Otherwise there's little to do: keep the bed weed-free and water only if the autumn is dry. It needs no feeding.

The first leaves are ready six to eight weeks after sowing, so a September sowing gives salad from about October or November. From then on you can pick right through to April.

Cut the leaves with a sharp knife 0.4–0.8 in above the soil and leave the heart of the rosette alone. The plants grow back from the centre, and you can cut the same plants three to six times before they flower. Picking only the outer leaves works too.

The whole plant is edible: leaves, stalks, the plate-like leaf around the flower stem and the small white flowers. It tastes mild and fresh, a little like lamb's lettuce, and wilts like spinach if you cook it. Winter purslane is considered low in nitrate compared with other winter leaves. Like spinach and chard, though, it contains oxalic acid, so enjoy it as part of a mixed salad rather than by the bowlful every day, especially if you're prone to kidney stones.

Picked leaves keep for about a week in the fridge, loosely wrapped in a damp cloth or bag.

Winter purslane is largely free of pests and diseases. The one real threat is slugs and snails on young seedlings in a mild, damp autumn. Check the bed in the evenings and keep the edges free of long grass and hiding places.

If your seed doesn't come up, the soil was most likely too warm. Wait for cooler weather and sow again.

In spring, from about March, the plants start to flower and the harvest winds down. Leave a few to set seed and they will drop it and come back by themselves the next autumn. That is handy, but it can spread around the garden. The seedlings are shallow-rooted and easy to pull.

Winter purslane belongs to the Montiaceae family, which has no close relatives among the usual vegetables. It doesn't fit any of the standard rotation groups and shares no particular pests or diseases with them, so you can slot it into any bed that's free over winter.

We found no tested companion pairings for winter purslane, and mixed-planting tables rarely mention it. In practice it sits happily alongside other winter leaves such as lamb's lettuce, winter lettuce and spinach in a cold frame or under fleece, because they all want the same cool, moist conditions. That's convenience, not a companion effect.