How to Extend Your Growing Season

The UK growing season for tender crops is frustratingly short. Frost risk in spring delays outdoor planting. Early autumn frosts end the season before many crops have reached their potential. The growers who get the most from their plots are the ones who work strategically at both ends of the season.

Start earlier with protection

Cloches, cold frames, and fleece allow you to sow or plant two to four weeks earlier than you could safely do without them. A cloche over a row of carrots in early March warms the soil and protects emerging seedlings. A cold frame full of lettuce transplants in late February can give you harvests by April.

Fleece (horticultural fleece, sometimes sold as frost protection fleece) is one of the most useful and affordable pieces of equipment in a vegetable garden. Laid over plants or young seedlings, it raises the temperature underneath by a few degrees, which is often the margin between survival and a frost kill.

A polytunnel or greenhouse extends the season at both ends

If you have the space and budget, a polytunnel or greenhouse transforms what is possible. Tomatoes, peppers, aubergines, and cucumbers that struggle to produce reliably outdoors in most UK locations perform consistently under cover. The season begins earlier and ends later.

A small unheated greenhouse is enough to extend your season significantly. Add a small heater and you can overwinter tender plants and start seeds in January without any additional indoor setup.

Succession sow for continuous harvest

Extending the season is not only about adding weeks at each end. It is also about keeping harvests coming throughout the middle of the season rather than having a glut followed by a gap.

Sow salad leaves, radishes, and spring onions every two to three weeks from March through to August. Each sowing gives you a harvest window of two to four weeks before bolting or becoming overmature. A consistent programme of small sowings produces continuous harvests from early spring to late autumn.

Tony O'Neill succession sowing small seeds into module trays filled with perlite-rich compost, demonstrating early season seed starting techniques to extend the vegetable growing season — Tony O’Neill sowing small seeds directly from the palm of his hand into module trays filled with quality compost and perlite. Succession sowing at regular intervals is one of the most effective ways to extend your harvest window and keep crops coming throughout the season rather than everything arriving at once.

Choose varieties for extended seasons

Some varieties are bred specifically for early sowing, late harvesting, or bolt resistance that extends the useful harvest window. Seek out varieties described as early, bolt-resistant, or overwintering when selecting seeds.

Hardy winter salad crops like land cress, winter purslane, corn salad (lamb’s lettuce), and certain Asian greens will provide harvests well into winter with minimal protection.

Finish later with protection

A fleece cover over tomatoes or peppers in September can extend their season by two to four weeks as overnight temperatures drop. Straw mulch around root vegetables left in the ground insulates them against frost and keeps them harvestable into winter.

Leeks, parsnips, swede, kale, and Brussels sprouts are all hardy enough to remain in the ground through UK winters and harvest as needed. Plan to have these crops in the ground to bridge the hungry gap between summer crops and spring sowings.

Tony O’Neill is a vegetable growing expert at Simplify Gardening. More on seasonal growing in Simplify Vegetable Gardening.