When Can You Plant Tomatoes Outside in the UK?

Tomatoes are one of the most versatile and widely grown fruits in the UK, whether in gardens or allotments, in pots or hanging baskets. However, choosing the best time to plant tomatoes outdoors can be a tricky business, considering the unpredictable weather and varied climatic conditions across the country.

Factors to Consider When Planting Tomatoes Outdoors

The timing of planting tomatoes outdoors depends on several factors:

Location: The UK has varying microclimates, which means that the weather conditions can differ significantly from one location to another. Hence, the timing of planting tomato plants outdoors is affected by your region and microclimate. For instance, Scotland has a shorter growing season than southern England, and coastal regions generally have cooler temperatures and more rainfall than inland areas.

Variety: Different tomato varieties have varying ripening periods, which affects planting time. For example, a cherry tomato ripens faster than a beefsteak tomato, making it suitable for planting earlier in the year. Also, different varieties have varying tolerances to cold temperatures, so it's essential to choose the right tomato variety for your region and microclimate.

Planting Site: The location where you intend to plant your tomatoes outdoors is also crucial for determining the ideal planting time. Tomatoes require a sunny, sheltered site with fertile, well-drained soil to grow and produce fruit. Hence, you need to consider the soil temperature and the possibility of late frosts, which can damage or kill young tomato plants.

The Best Time to Plant Tomatoes Outside in the UK

The best time to plant tomatoes outside in the UK is between late May and early June, after the risk of frost has passed, and the soil has warmed up to a temperature of at least 12°C. However, if you live in a colder region, you may need to delay planting until June or July. In southern England, you can start planting earlier, from mid-May, provided you have an early-ripening variety, and the soil is warm enough.

It's essential to condition the soil before planting by removing weeds, digging in compost or well-rotted manure, and adding a balanced fertiliser to improve soil fertility. It would help if you also hydrated the soil generously in advance to ensure that the roots have ample moisture to establish and grow.

Alternative Ways to Grow Tomatoes

Aside from outdoor planting, there are alternative ways to grow tomatoes in the UK, including:

Greenhouse Tomatoes: If you have access to a greenhouse or polytunnel, you can grow tomatoes all year round, starting as early as January or February. Greenhouses provide better climate control, shelter from adverse weather conditions, and protection from pests and diseases. However, they require regular watering, feeding and pruning to maximise yield and quality.

Container Tomatoes: If you don't have a garden or enough space, you can grow tomatoes in containers or hanging baskets on your patio or balcony. Container-grown tomatoes require more watering and feeding than outdoor plants, and you need to make sure that the soil and drainage are adequate. You can start container tomatoes from April or May, depending on your region and microclimate.

Window Sill Tomatoes: If you have a sunny window sill, you can grow cherry tomatoes or bush tomatoes indoors or on a windowsill. Window sill tomatoes, however, require more attention, such as frequent watering and feeding, and may not achieve a high yield because of their limited space and light.

Tips for Growing Healthy Tomatoes Outdoors

To grow healthy, vigorous tomatoes outdoors in the UK, you need to:

Choose the right variety: Select a tomato variety that is suitable for your region and growing conditions, such as an early-ripening variety for colder regions or a disease-resistant variety for humid climates.

Prepare the soil: Improve soil fertility by adding organic matter, such as compost or manure, and a balanced fertiliser to ensure that your tomato plants have access to vital nutrients.

Plant at the right time: Wait until the risk of frost has passed, and the soil has warmed up to planting temperature. Plant your tomato seedlings at a depth of approximately 2.5cm, leaving a spacing of 45-60cm between plants, depending on the tomato variety.

Water and feed regularly: Water your tomato plants regularly, keeping the soil consistently moist but not waterlogged. Feed your tomato plants with a high potassium fertiliser, such as tomato fertiliser, every two weeks from the onset of flowering until the end of fruiting.

Prune and train: Remove the side shoots of your tomato plants to channel their energy into the main stem, and provide support to the stem with stakes or cages to prevent them from collapsing under the weight of the fruit.

Watch out for pests and diseases: Keep an eye out for common tomato pests and diseases, such as aphids, tomato hornworms, blight or blossom-end rot, and treat them promptly with organic or chemical solutions as appropriate.

Conclusion

Planting tomatoes outdoors in the UK at the right time and under the appropriate conditions can yield a bountiful harvest of juicy, flavourful tomatoes that you can enjoy all summer long. By considering the factors that affect tomato growing, choosing the right variety, preparing the soil, and providing adequate care and attention, you can achieve success with your tomato garden, regardless of your location or growing space.