From garden to table: Living seasonally with a polytunnel

Growing your own food year-round gives you fresh produce, but it also reconnects you with natural cycles and reduces reliance on supermarket shelves. As UK home production of vegetables increased by 2.1% to just over £2 billion in 2024, more growers are discovering that a polytunnel bridges the gap between garden and kitchen by extending control over microclimate and timing. For those wondering whether investing in a polytunnel proves worthwhile, the answer is in understanding how this structure allows for seasonal eating and adjusting what you grow to light, temperature, and the rhythms of the year.

1. Extending the Seasons: How a Polytunnel Shifts the Growing Window

A polytunnel functions as effective season extension technology, protecting crops against frost, wind, and excess rainfall whilst allowing earlier sowing and later harvesting. The transparent polythene covering allows sunlight to penetrate whilst trapping warmth inside, creating a microclimate several degrees warmer than the surrounding environment. When shielding plants from harsh weather conditions, a well-designed polytunnel greenhouse can boost indoor temperatures by several degrees, allowing you to sow early and protect against late frosts. This temperature advantage, typically two to five degrees during daytime, means tender crops can start weeks earlier in spring and continue producing well into autumn.

2. Crop Planning Through the Year: What to Grow, When

Maximising the extended growing window needs thoughtful succession planting and crop rotation. In early spring, cool-season crops such as salads, brassicas, and peas can begin whilst outdoor temperatures remain too low. As warmth builds through May and June, transition to warm-season crops, including tomatoes, peppers, and cucumbers. Late summer presents an opportunity for a second wave of cool-season plantings, such as autumn salads, oriental greens, and overwintering crops like perpetual spinach and hardy kale. Succession planting allows growers to maintain continuous harvests by staggering sowings at intervals, ensuring productive beds throughout the year. This strategic approach prevents seasonal gluts whilst maintaining consistent supply across twelve months rather than six to eight.

3. Practical Design, Climate and Innovation Considerations

Effective polytunnel management depends on understanding orientation, ventilation, thermal mass, and innovative technologies. In the UK, positioning your structure east to west maximises winter sunlight whilst lowering summer overheating. Adequate ventilation proves very important. This is because doors, roof vents, and side panels allow hot air to escape, whilst thermal mass materials such as water barrels absorb daytime heat and release it gradually at night. Recent innovations include heat-responsive films that regulate internal temperatures automatically, reducing manual management. However, challenges remain: overheating during heatwaves requires shade cloth or additional ventilation, whilst managing humidity prevents fungal diseases.

4. From Tunnel to Table: Harvest, Storage and Use

Moving produce from polytunnel to plate requires consideration of harvest timing, preservation methods, and menu planning. Staggered planting allows for continuous small harvests rather than overwhelming gluts. Preservation techniques extend the polytunnel's value: freezing soft fruits and prepared vegetables, pickling cucumbers and beetroot, drying herbs and chillies, or storing root crops in sand all capture summer abundance for winter use. Planning meals around what's ready encourages genuine seasonal eating, for example, courgette flowers in June, abundant tomatoes in August, and winter greens through January.

Living seasonally with a polytunnel is a fundamental shift towards understanding food production cycles, appreciating seasonal abundance, and developing resilience through homegrown supplies. The investment pays dividends not just in produce volume but in knowledge gained and the satisfaction of serving genuinely seasonal food from garden to table.