Polytunnel gardening is a fantastic way for beginners to extend the growing season and create a productive garden space that can yield fresh produce and flowers all year round.
Whether you’re looking to grow your own vegetables, herbs, or flowers, a polytunnel provides the perfect environment to cultivate a wide variety of plants.
For those new to this type of gardening, choosing fast growing plants is a great way to gain confidence and enjoy quick results. In this article, we’ll explore some of the best fast-growing vegetables, herbs, and flowers you can grow in your polytunnel from seed.
Fast Growing Plants: 5 Vegetables for a Polytunnel Gardener to Grow from Seed
Starting with vegetables is an excellent way to make the most of your polytunnel. These fast-growing vegetables will not only provide you with a quick harvest but also help you make the most of your gardening space.
1. Cress
Cress is one of the fastest-growing vegetables, making it ideal for beginners who want to see results quickly. It can be grown year-round in a polytunnel, and you can harvest it within just a few weeks. Cress seeds are tiny and can be sprinkled directly onto the soil. They don’t require much care—just keep the soil moist, and you’ll have fresh cress to add to your salads and sandwiches in no time.
Cress is also a nutritious choice, packed with vitamins A, C, and K. Its slightly peppery flavour adds a nice kick to dishes, and because it grows so quickly, you can sow successive batches every few weeks to ensure a continuous supply.
2. Loose-leaf Lettuce
Loose-leaf lettuce is another great option for beginners. Unlike head lettuce, which takes longer to mature, loose-leaf varieties can be harvested in as little as 30 days. This makes them perfect for those looking to enjoy fresh greens without the wait.
You can start harvesting the outer leaves once they reach a size that you like, leaving the plant to continue growing. This “cut-and-come-again” method allows for multiple harvests from a single plant.
Loose-leaf lettuce grows well in the cooler temperatures of early spring and late autumn, but it can also thrive throughout the summer if kept well-watered and shaded during the hottest part of the day.
3. Radishes
Radishes are known for their rapid growth, often maturing in just 3 to 4 weeks. These crunchy, peppery vegetables are incredibly easy to grow and make an excellent choice for polytunnel gardening. Radishes are also quite versatile—they can be used in salads, pickled, or eaten as a crunchy snack.
Sow radish seeds directly into the soil and thin them out as they grow. They do best in cooler weather, so they’re a perfect crop for early spring or autumn. You can also interplant radishes with slower-growing vegetables, such as carrots, to make the most of your space.
I recommend varieties ‘Cherry Belle’ and ‘French Breakfast’ , for example, which are especially fast-growing and reliable, ensuring a quick and satisfying harvest.
4. Rocket
Rocket, also known as arugula, is a peppery green that adds a distinctive taste to salads and other dishes. It’s incredibly fast-growing, with some varieties maturing in just 20 days. Rocket is easy to grow from seed and thrives in a polytunnel, where it can be protected from pests like flea beetles.
Rocket prefers cooler temperatures and can be grown almost year-round in a polytunnel. It’s a great crop to sow in succession, ensuring a continuous supply of fresh greens. To harvest, simply cut the outer leaves and let the inner ones continue growing.
This leafy green is rich in vitamins A and C, making it a healthy addition to your diet. Plus, its unique flavour can liven up any salad or sandwich.
5. Pak Choi
Pak choi, also known as bok choy, is a fast-growing Asian green that does exceptionally well in a polytunnel. It can be harvested as baby leaves in as little as 30 days, or you can let it mature fully in about 45 days. Pak choi is a versatile vegetable that can be used in salads, stir-fries, or steamed as a side dish.
When growing pak choi, it’s best to sow seeds directly into the soil and thin them out as they grow. They prefer cooler temperatures, so they’re a great crop for spring and autumn planting. Pak choi can also be grown as a cut-and-come-again crop, providing multiple harvests from a single planting.
Pak choi is not only quick to grow but also packed with nutrients like vitamins C and K, calcium, and antioxidants, making it a nutritious addition to your polytunnel garden.
Fast Growing Plants: 5 Herbs for a Polytunnel Gardener to Grow from Seed
Herbs are a must-have in any garden, and they grow particularly well in the controlled environment of a polytunnel. Here are some of the fastest-growing herbs that are perfect for beginners:
6. Basil
Basil is a popular herb that’s easy to grow and matures quickly, making it ideal for beginner gardeners. Within about 4 to 6 weeks, you can start harvesting its aromatic leaves. Basil thrives in the warm, sheltered environment of a polytunnel, where it can be protected from cold drafts and sudden temperature drops.
Basil is perfect for adding to pasta dishes, salads, and sauces. To encourage bushier growth, pinch off the top leaves regularly, which will also help prevent the plant from flowering too early.
It can also be grown alongside tomatoes, as the two plants complement each other both in the garden and on the plate.
7. Coriander
Coriander, also known as cilantro, is another fast-growing herb that’s well-suited to a polytunnel. It’s a dual-purpose plant—both its leaves and seeds are used in cooking, offering a bright, citrusy zing (for some) to a variety of dishes. Others however, cannot stand the taste and it turns out this is a genetic issue.
Coriander can be harvested as early as 3 to 4 weeks after sowing. It grows best in cooler temperatures, so it’s ideal for spring and autumn planting. However, in a polytunnel, you can extend its growing season and enjoy fresh coriander for longer.
To keep coriander producing leaves, it’s important to harvest regularly and not let it go to seed too quickly, as the plant tends to bolt in hot weather. If it does bolt, don’t worry—you can still harvest the seeds and use them as a spice in curries and other recipes.
8. Dill
Dill is a fast-growing herb that can be harvested within 4 to 6 weeks of sowing. Dill is particularly popular for flavouring fish dishes, pickles, and salads.
It prefers a sunny spot in your polytunnel and well-drained soil. Like coriander, dill can also bolt in hot weather, so regular harvesting will help keep the plant producing leaves.
In addition to its culinary uses, dill is also a good companion plant, attracting beneficial insects like hoverflies and ladybugs, which help keep pests in check.
9. Parsley
Parsley is a versatile herb that’s easy to grow and matures relatively quickly. Depending on the variety, you can start harvesting parsley within 6 to 8 weeks of sowing. Parsley is a biennial plant, meaning it will continue to produce leaves in its second year, although the taste is best in the first year.
It’s an excellent herb to have on hand for garnishing, adding to salads, and using in other dishes.
10. Chervil
Chervil is a lesser-known herb that’s quick to grow and easy to cultivate in a polytunnel. It’s similar in appearance to parsley but has a more delicate taste, often described as a cross between parsley and anise. Chervil is commonly used in French cuisine, particularly in sauces and soups.
Chervil grows best in cool, shady conditions, making it perfect for spring and autumn planting in a polytunnel. It can be harvested within 6 to 8 weeks of sowing and should be picked regularly to encourage new growth. This herb is also a good companion plant for other vegetables, as it helps to repel aphids.
Fast Growing Plants: 10 Flowers for a Polytunnel Gardener to Grow From Seed
Flowers can add beauty and colour to your polytunnel, as well as attract beneficial insects to help with pollination. Here are some of the fastest-growing flowers that are perfect for beginners:
11. Calendula
Calendula, also known as pot marigold, is part of the fast growing plants that’s incredibly easy to grow from seed. It can bloom as early as 6 to 8 weeks after sowing, producing bright orange or yellow flowers that add some vibrancy to your polytunnel.
Calendula is known for its medicinal properties and is an excellent companion plant, as it helps to deter pests and attracts pollinators like bees. The flowers are edible too and can be added to salads and other dishes.
12. Cornflowers
Cornflowers are another fast-growing flower that’s easy to grow from seed. These hardy annuals can bloom in as little as 8 weeks, producing striking blue flowers that attract bees and other pollinators.
They are excellent for cutting and can be used in fresh or dried flower arrangements, have a long history of medicinal use, and edible petals.
13. Cosmos
Cosmos are tall, elegant flowers that grow quickly and bloom prolifically in a polytunnel. They can start flowering within 8 to 10 weeks of sowing and will continue to produce blooms throughout the summer and into autumn.
Cosmos are very easy to grow, making them ideal for beginners. They attract beneficial insects, including bees, butterflies, and hoverflies.
14. Marigolds
Marigolds are also among the fastest-growing flowers, often blooming within 6 to 8 weeks of sowing. They’re a staple in many gardens due to their bright, cheerful flowers and their ability to repel pests.
Marigolds are very versatile and can be used in borders, containers, or as companion plants in vegetable beds. They can deter nematodes, repel aphids, and attract beneficial insects like ladybirds.
15. Nasturtiums
Nasturtiums are fast-growing, easy-to-grow flowers that can start blooming within 6 to 8 weeks of sowing. They’re known for their bright flowers and attractive foliage, which are edible as well as attractive.
In the garden, nasturtiums are excellent companion plants, as they attract aphids away from other crops and can help deter whiteflies and cucumber beetles.
16. Nigella
Nigella, also known as love-in-a-mist, is a charming, fast-growing flower that can bloom in as little as 8 weeks. Its delicate, lacy foliage and unique, star-shaped flowers make it a beautiful addition to any polytunnel garden.
It’s also a self-seeding annual, so once you plant it, it’s likely to come back year after year. The flowers attract pollinators, and the seed pods can be used in dried flower arrangements or harvested for their edible seeds, which are commonly used as a spice in cooking.
17. Poppies
Poppies are another fast-growing flower that’s perfect for beginners. They can bloom within 8 to 10 weeks of sowing, producing vibrant, papery flowers in shades of red, pink, orange, and white.
They’re also excellent for attracting pollinators to your garden and are known for their medicinal and culinary uses—some varieties produce edible seeds that can be used in baking, for example.
18. Sunflowers
Sunflowers are fast-growing, iconic flowers that are sure to bring joy to any polytunnel garden. They can start blooming within 8 to 10 weeks of sowing, producing tall, majestic flowers that can reach heights of up to 12 feet.
Sunflowers are very easy to grow and require little maintenance. They’re also excellent for attracting pollinators, including bees and butterflies, to your polytunnel.
In addition to their beauty, sunflowers have practical uses – the seeds can be harvested and eaten, and the plants themselves can provide shade for other crops during the hottest part of the summer.
19. Sweet Alyssum
Sweet alyssum is a fast-growing, low-growing flower that’s perfect for edging borders or filling in gaps in your polytunnel garden. It can start blooming within 6 to 8 weeks of sowing and will continue to produce fragrant, white, pink, or purple flowers throughout the season.
Sweet alyssum is very easy to grow and requires little maintenance. It’s also an excellent companion plant, as it attracts beneficial insects like hoverflies, which help control aphids and other pests.
20. Zinnia
Zinnias are fast-growing, vibrant flowers that can start blooming within 8 to 10 weeks of sowing. They are very easy to grow from seed and thrive in the warm environment of a domestic polytunnel. They’re also excellent for attracting pollinators, including bees and butterflies.
In addition to their beauty, zinnias are great for cutting and can be used in fresh or dried flower arrangements. They’re also drought-tolerant, making them a low-maintenance option for your polytunnel garden.
FAQs
What flower takes the most time to grow?
Amorphophallus titanum also known as the “corpse flower” can take several years, sometimes up to a decade or more, to bloom. Among garden flowers, however, one flower that requires patience is the perennial peony, which may take 2-4 years to bloom.
What is the easiest flower to grow?
The Marigold is often considered one of the easiest flowers to grow, making it a favourite among beginner gardeners. However, remember that the easiest flowers for each gardener will depend on the conditions where they live. The easiest flowers to grow are often native plants, ideally suited to the specific climate and microclimate conditions.
Sources
BBC Gardeners’ World Magazine. (2024) How to grow cosmos. Gardener’s World .[online] Available at: https://www.gardenersworld.com/how-to/grow-plants/how-to-grow-cosmos/ [accessed 21/08/24]
Boeckmann, C., (2024) How to Grow Nasturtiums: The Complete Nasturtium Flower Guide. Almanac. [online] Available at: https://www.almanac.com/plant/nasturtiums [accessed 21/08/24]
