Winter Salad Without the Meter Running: The Case for a Cold Frame

By early November 2026, most UK gardens have that end-of-season look: wet paths, bare branches and a few heroic leaves still hanging on. The catalogues, meanwhile, are busy pushing heated greenhouses as the answer to winter growing. They are lovely things, but if your goal is a steady cut of salad leaves, a few herbs and some overwintering greens, the humble cold frame is usually the smarter purchase.

It is not a glamorous bit of kit. It does not hum, glow or connect to an app. That is rather the point.

What a cold frame actually does

A cold frame is simple: a bottomless box with a transparent lid, set over soil or a raised bed. It shelters plants from wind, driving rain and the worst of the frost, and it traps a little daytime warmth in the soil and air. On a sunny November day it can feel surprisingly mild inside. On a clear night it will not keep tender plants alive, but it will take the edge off the cold.

In a UK winter, light is the real limit. A heated greenhouse can persuade plants to keep growing when there is not enough sun to support that growth, which often means soft, stretched leaves and a battle with condensation and mould. A cold frame is more honest. It slows plants down, protects what is already there and gives hardy crops a fighting chance.

Why it wins on cost and simplicity

A heated greenhouse in winter is an expensive way to grow a few leaves. You are paying for heat, and often for a fan or thermostat as well, while daylight is at its lowest. In a cold frame, the running cost is zero. You open the lid when it is mild, close it before the afternoon chill, and keep an eye on the weather.

That simplicity matters. Most gardeners do not want a second job in December. A cold frame asks for a minute or two of attention on mild days and a bit of judgment when a cold snap is forecast. If you are forgetful, an automatic vent opener is a worthwhile upgrade, but even a manual lid will do.

Siting and setting up

Put the frame somewhere sunny and sheltered, ideally facing south or south-west. A spot at the bottom of a slope, under a hedge or against a north-facing wall will collect cold air and stay damp. Good drainage matters too, so place it on gravel, paving or a raised base rather than in a puddle-prone corner.

Clean the glazing before winter. Grubby glass or cloudy polycarbonate cuts light, and light is the one thing you cannot buy more of in November. A brick path or wall nearby can store a little warmth, but do not overcomplicate it. Sun, shelter and drainage are the main events.

Crops that earn their place

Hardy salad leaves are the stars. Lamb's lettuce, also called corn salad, is reliable and mild. Land cress gives a peppery kick. Mizuna and mustard greens add bite and colour. Winter lettuce varieties such as 'Winter Density' can be picked leaf by leaf, and spinach 'Giant Winter' will often hold on through the colder months. Chard, parsley and chervil are worth a go too.

The best sowings are usually made in late summer or early autumn, so the plants are established before the light fades. A November sowing will be slow, and in a cold frame it is more of a gamble. If you are sowing now, use fleece inside the frame and expect small, steady pickings rather than a flush. Do not try to force basil or tender herbs through winter; they will sulk, rot or both.

Ventilation, water and frost

Ventilation is where cold frames are won or lost. On a mild, bright day, prop the lid open for an hour or two, even in November. Trapping damp air inside is a recipe for grey mould and slugs. Close the lid by mid-afternoon so the frame can store what warmth it can before nightfall. If condensation is running down the glass every morning, you need more air.

Water sparingly and in the morning. Winter salad does not need much, and wet soil plus cold air is a bad combination. A layer of fleece or bubble wrap inside the frame can add protection during a cold snap, but do not smother the plants. Check for slugs and snails regularly, because a cold frame is a five-star hotel for them.

A practical buying checklist

Size matters more than you think. A frame that is too small will be full before Christmas. Look for something with a decent height, ideally 45–60cm, so leaves are not pressed against the glazing. Hinged lids with sturdy stays are much easier to use than a loose pane you have to prop with a brick.

Timber frames look lovely, insulate well and feel warm and solid. They are heavier and will need occasional treatment to stop rot. Aluminium frames are light, rust-free and easy to move, but they can rattle in wind and offer less insulation. Glass gives the best light but is heavy and breakable; twin-wall polycarbonate is safer, lighter and better insulated, though it can yellow over time.

Check the base, the drainage and the fixings. A cheap frame that blows over in a gale is not a bargain. If you want to compare practical options for UK gardens, the Seasonal Planting range at grogardenproducts.co.uk is a sensible place to start.

The realistic payoff

A cold frame will not give you tomatoes in January, and it will not match a heated greenhouse for sheer range. What it will do is keep a few salad leaves, herbs and greens coming when the shops are selling limp bagged leaves at winter prices. For most gardeners, that is the winter-growing win worth having.