How to Grow Your Own Salad Bar in a Polytunnel All Year Round

Everyone loves a fresh salad, but did you know that you can easily grow a range of salad accessories in your garden? Especially if you have a polytunnel! In this article, we will explore how to grow your own salad bar in a polytunnel all year round, using crops including lettuce, basil, tomatoes, and more, as well as sowing, nurturing, and harvesting your own fresh greens and vegetables.

Key Points:

• Discover the best plants for your polytunnel salad bar, including lettuce, spinach, and more.
• Learn sowing techniques and care tips to maximise growth and flavour for your homemade salad.
• Understand the best harvesting times for each plant to ensure your crops remain fresh for your salad bar.

Starting Your Polytunnel Salad Garden

Greens, vital for any salad, are more than just your average lettuce; they include a variety of edible plant leaves that thrive in cooler seasons of spring and autumn. Many greens are incredibly versatile, making them perfect to grow in a polytunnel environment, especially with how they provide gardeners with the right nutrients that can be used for more than just salads. Greens also make for great companion plants too.

Choosing Greens for Your Polytunnel

When planning your polytunnel garden, consider a range of greens that not only suit fresh salads but can also be used for cooking. Your most common greens that can be eaten fresh and raw or cooked include:

• Cress
• Kale
• Lettuce
• Mache
• Mesclun

11 Best Crops To Grow For Your Salads

With that being said, let’s look at the best crops that you can grow in your polytunnel ready to add to your salad bar when the time comes to harvest them:

1.    Lettuce

Lettuce is a staple in salad growing and thrives under the controlled conditions of a polytunnel.

• To start, sow seeds about 1/4 inch deep indoors or directly in the garden when the soil temperature reaches 50 degrees Fahrenheit.
• Ensure your seedlings are well spaced—beginning with five per square foot. This technique allows you to consume some while letting others mature.
• To avoid gaps in availability, plant new lettuce seeds every two to four weeks. This rotation strategy keeps your polytunnel producing crisp, tender lettuce all season long.
• Remember, lettuce is sensitive to heat, so provide some afternoon shade and maintain consistent moisture levels to keep it thriving.

2.    Peas

Peas are another excellent addition to your polytunnel salad bar.

• Plant them 1 inch deep as soon as the soil is workable, spacing them out nine to 16 plants per square foot.
• Peas need support, so set up string or wire trellises early on to help them climb.
• For those looking to extend their growing season, consider planting a second batch six to eight weeks before the first frost.
• Peas are quite robust and benefit from adding a legume inoculant to the soil to boost their growth.

3.    Broccoli

Broccoli is a naturally hardy crop that can be easily grown in the colder months, and can be started indoors by sowing seeds 1/4 inch deep, six weeks before the last spring frost.

• Once the seedlings develop a couple of leaves, transplant them to your polytunnel, giving each plant about a square foot of space.
• Broccoli is frost-hardy and can be harvested 50 to 70 days after transplanting.
• Adding row covers can help protect against common pests like cabbage worms.

4.    Kale

Kale is exceptionally versatile and nutritious, making it a great choice for your polytunnel during the cooler months.

• Plant kale seeds or seedlings about 18 inches apart in all directions to give them room to expand.
• Top the soil with compost and protect the young plants with insect mesh to fend off pests.
• Kale leaves can be harvested as needed.

5.    Tomatoes

No salad bar is complete without some vibrant, juicy tomatoes.

• Start your tomatoes indoors, planting seeds 1/4 inch deep, six to eight weeks before the last frost.
• Transplant them into the polytunnel when the soil temperature reaches 65 degrees Fahrenheit, allowing one square foot per plant.
• Tomatoes take between 55 and 100 days to reach maturity, depending on the variety.
• Prune lower leaves and bury the stems deeper into the soil to encourage a strong, healthy root system.

6.    Spinach

Spinach, a staple in salad growing, thrives in the cool environment of a polytunnel.

• Plant seeds directly in the garden soil about 1/2″ deep, up to six weeks before the last frost.
• For a continuous supply, sow a new batch every two weeks during spring and again in late summer for fall harvesting.
• Thin the seedlings to about nine plants per square foot to give each one enough space to mature. Spinach is ready to harvest within 30 to 40 days from germination and is known for its frost-hardiness.
• Be mindful that spinach can bolt in hot weather, so be sure to harvest leaves early and keep the soil cool and moist with mulch or shade netting.

7.    Swiss Chard

Swiss chard can also be added to your polytunnel, adding a splash of colour to your salad growing efforts.

• Start by planting seeds 1/2″ deep, either indoors six weeks before the last frost or directly in the garden two weeks before.
• Swiss chard should be transplanted around the time of the last frost and can be planted again mid-season to ensure a continued supply of its tender leaves.
• Space your plants about two per square foot.
• Swiss chard is ready to harvest as baby greens 30 days from seeding and reaches full size in about 50 days.
• This plant thrives in both cool and warmer temperatures, making it a versatile choice for any garden.

8.    Peppers

For those looking to add variety to their polytunnel, peppers and eggplants are perfect.

• Start peppers indoors, sowing seeds 1/4″ deep about 10 to 12 weeks before the last frost.
• Transplant them into the garden three weeks after the last frost when the soil temperature reaches about 70 degrees Fahrenheit.
• Space them one plant per square foot.
• Peppers take between 50 to 85 days to reach maturity, depending on the variety and whether you’re harvesting them green or fully coloured.

9.    Eggplants

Eggplants require similar conditions to peppers.

• Start them indoors 1/4″ deep, eight weeks before the last frost.
• They should be transplanted when the soil temperature is around 70 degrees Fahrenheit, spacing them one per square foot. It takes about 55 to 70 days from transplant for eggplants to be ready for harvest.
• Protect these plants with garden fabric as they are prone to pest attacks even after flowering.

10.    Cucumbers

When discussing what salad crops to grow, we cannot forget about cucumbers; they are indispensable for anyone dedicated to growing salad for their homemade salad bar.

• Plant cucumber seeds indoors 1/2″ deep about three weeks before the last frost, or directly in the garden thereafter.
• For bush types, space one plant per square foot, and for vining types, use two per square foot.
• A second planting two weeks later can extend your harvesting period.
• Cucumbers are typically ready to pick 50 to 60 days after transplanting.

11.    Basil

When growing basil:

• Start seeds indoors 1/4″ deep six weeks before the last frost or outdoors two weeks after.
• Once the seedlings are established and the soil is warm, transplant them, spacing two per square foot.
• Basil should be harvested 40-55 days after transplanting.
• Pinching the stems regularly encourages a bushy growth and prolongs the harvesting window.

 

In conclusion, growing salad greens and vegetables in a polytunnel allows gardeners to create their own salad bar and enjoy the fruits of their labour with fresh, nutritious produce. By following specific planting, care, and harvesting guidelines for each plant type shown in this guide, any gardener can decorate their garden or polytunnel with these crops.

FAQs

What is a polytunnel and why should I use one for growing salads?

A polytunnel is a tunnel-like structure made from polyethylene used to protect plants from harsh weather and extend growing seasons. It’s ideal for salads because it creates a controlled environment that can improve growth throughout the year.

Can I grow other vegetables alongside salad greens in my polytunnel?

Absolutely! Companion planting can be beneficial. For example, radishes can be grown alongside lettuce as they mature quickly and can help deter pests.

Sources

Covington, L., (2022) What Is Mesclun? The Spruce Eats. [online] Available at:

https://www.thespruceeats.com/what-is-mesclun-4774443 [accessed 18/03/2025]

 

About the Author

Sean Barker is the Managing Director of First Tunnels and a passionate advocate for sustainable gardening.

With over 30 years of experience in the gardening industry, Sean has dedicated himself to helping gardeners across the UK maximise their growing potential through the effective use of polytunnels. His blog offers a wealth of practical tips, expert advice, and innovative solutions for maintaining and optimising polytunnels, ensuring gardeners can enjoy bountiful harvests all year round. Sean can often be found experimenting with new growing techniques in his own polytunnel, always eager to share his findings with fellow enthusiasts.

 

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