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All you need to know

Sweet Peppers

With a wide choice of colours, shapes and sizes, this is a crop that definitely boasts bags of character. Anthony Bennett explains how to get the most from your pepper plants

Home-grown sweet peppers are exceptionally delicious and will save you a fair few bob on shop-bought fruits. They’re easier to grow than tomatoes and suffer less from pests and diseases too. But perhaps the biggest draw of growing your own peppers is the opportunity to explore the many varieties out there; the diversity of choice and the constant breeding of cultivars mean that up to 2,500 new varieties of sweet and chilli peppers are thought to be created every year! You’ll find a glut of choice in seed catalogues. The fruits range from the elongated, almost horn-like ‘Corno Rosso’ to more traditionally shaped types such as ‘Bell Boy’ or ‘California Wonder’.

Peppers can be a stunning addition to a kitchen garden – they can be grown in containers on the patio where their glossy foliage, white-hooded flowers and colourful fruits will brighten up your plot. The colours of shop-bought peppers are usually restricted to the traffic light-tones of red, amber and green but home-growers will have plenty more to choose from – expect to find bright yellow, cream, purple, orange and lime-green varieties too. The plants need minimal support and there are even dwarf types that are perfect for growing in window boxes or other containers.

Peppers hail from warmer, tropical climes, so you’ll need to ensure a sunny, sheltered position for your plants. In colder parts of the country they are best grown in a greenhouse or polytunnel. Given these basic requirements there’s no reason you shouldn’t expect to harvest at least three and up to eight peppers per plant.

Starting your crop from seed will give you the biggest possible choice of varieties and greatest control over what you’re growing, although there are also an increasing number of peppers that can be bought from garden centres or mail-order companies as young plants.

Preparation of their final growing position begins about a month before planting. If you want to grow your crop outside, pick a vigorous F1 hybrid variety and a spot that is in full sun. A south- or west-facing brick wall or fence is ideal, as the heat absorbed during the day will be reflected back towards the plants at night, ensuring a higher average temperature. Dig the soil over, incorporating a bucket-load of wellrotted manure or compost to enrich the ground. About two weeks before planting out, which will normally be at the end of May, place cold frames over the planting positions to warm the soil.

Greenhouse or polytunnel growing is the only reliable way to guarantee a crop of peppers in colder or exposed parts of Britain. Even in the south of England protection like this will mean more peppers to each plant. If you don’t have a greenhouse, you could try growing dwarf varieties in a cold frame of at least 50cm height. If you are planting into your greenhouse borders, fork a general purpose fertiliser, such as chicken manure pellets, into the soil a couple of weeks beforehand.

Raising peppers from seed is very straightforward as they have a high germination rate. Sow your seeds in March to give them at least two months to grow on before they are planted into their final positions. To get your seeds going, fill a 7cm pot with fresh seed compost and tap it to encourage the compost to settle. Make sure the surface is level before sowing the seeds individually, leaving a few centimetres between each one and including a maximum of about five per pot. Cover your seeds with a 0.5–1cm layer of compost or vermiculite. Keep your pots well-irrigated by placing them in a tray of water – the moisture will soak up from the base until the compost or vermiculite appears damp on the surface. Don’t forget to label the containers carefully if you’re growing a few varieties, it would be a shame to confuse them at this early stage!

Move your pots to a propagator or alternatively place a clear, plastic bag over the top of each one, securing it around the rim using an elastic band. It is best to start seeds off indoors, where no additional heat will be needed – a warm window sill should do the trick. If growing in a greenhouse you will need to ensure a minimum germination temperature of about 18°C, so a heated propagator will be necessary. Once your seedlings appear, usually within two to three weeks, uncover the pots and move them to a bright window sill to grow on. If you’re using a greenhouse maintain a minimum temperature of 15°C.

Keep seedlings moist and warm and they’ll begin to put on substantial growth. The young plants will need to be potted on, or pricked out, into their own 7cm pots once they reach about 2cm high. Fill pots with multipurpose compost and tap them to settle the growing medium. Carefully ease out the contents of the nursery pot, taking great care not to damage the young seedlings. Dibble holes into the compost of the new containers that will be large enough to take the roots. Handle seedlings by their leaves to avoid damaging their delicate stems and place them into the dibbled hole. Firm back compost around the roots so that the seedlings are buried to the same level as they were in their previous pots, before placing the pots in a bright, sunny spot.

You will need to keep the compost moist so that there is no check in the seedlings’ growth. When roots appear at the base of the pots, transfer them to a container that is 12cm in diameter, again using multipurpose compost.

The time for planting out can vary according to where you want to grow your peppers. Those intended for the greenhouse or polytunnel can be planted into position as soon as early May, giving the longest possible season of growth. Outdoor-grown types are best moved to their final placings after the date of the last frost – usually late May. They can be planted out sooner than this, so long as a cloche or horticultural fleece is on hand to protect them in the event of a surprise cold snap. Begin hardening plants off a few weeks beforehand by placing them outside for increasingly longer spells, or by positioning them inside a cold frame that is kept open during the day and shut at night. This will ensure they adjust to weather conditions outdoors before being moved to their permanent growing position. When planting out, leave 45cm between each pepper to give them enough room to spread.

The plants can also be transferred into grow bags, at three per bag, or kept in good-sized containers. Plant one pepper per 30cm container, or opt for a compost volume of at least five litres. Use John Innes No. 3 compost for container crops, as this will provide a steady growing environment that isn’t prone to drying out.

Peppers do not need the constant pinching out or tying in that many tomatoes require, even though they are closely related. Once the plants reach about 20cm in height they can, however, be tied loosely to canes using string to stop them swaying about. When they get to 30-40cm high, pinch out the tips of your plants to encourage them to bush out and form a more rounded plant that will be sturdier in habit.

Peppers love warm temperatures and it is rare that the weather will get too hot for them in our cool climate. However, greenhouse peppers can be scalded by the sun’s concentrated rays. Don’t run the risk of damaging foliage – apply a shade paint on the glass from early June, which will keep strong rays off plants without compromising light levels. Open vents and doors on hot days to ensure a steady through-flow of fresh air.

Flower formation is the signal to begin feeding plants. Use a liquid feed that’s suitable for tomatoes – a high-potash feed containing seaweed is ideal. Apply this every ten days as you water, or according to the packet instructions. This feed will help your plants to form more flowers and fruits. Keep plants weed-free and water them regularly to keep growth rates steady.

Pick peppers as soon as they are large enough. Most fruits start as green peppers, before ripening up to their ultimate colour. When harvesting fruits do not, on any account, simply tug the pepper from the plant as you will damage it. Cut away fruits using a sharp knife or a pair of secateurs and your plants will remain unscathed.

Most plants won’t begin producing peppers until at least mid July, although seed started off much earlier may produce a few fruits before this. Outside-grown peppers will follow on a few weeks later and will continue into early autumn. If there are still unripened fruits when the frosts return in October dig up plants by their roots and hang them upside down in a dry, sheltered spot so that they can finish ripening.


  • January

    Make sure greenhouses and polytunnels are thoroughly cleaned and sterilised this month to kill off overwintering pests such as the sap-sucking red spider mite.

  • February

    Begin sowing the earliest peppers this month. Start them off in pots placed into a heated propagator or covered with clear plastic.

  • March

    This is the main month for sowing peppers. Use good, clean seed or multipurpose compost and maintain a temperature of at least 18°C.

  • April

    Prick out the seedlings into their own pots using multipurpose compost. Keep seedlings moist for speedy and troublefree growth.

  • May

    Pot on plants as they grow and plant them out after the last frost. Make sure plants are hardened off beforehand.

  • June

    Start feeding plants with a liquid feed as soon as the first flowers appear. Pick one that is high in potash and also suitable for tomato plants.

  • July

    Begin picking fruits this month and continue through until the first frosts. Expect to grow three to eight fruits per pepper plant.

  • August

    Don't be caught out by red spider mite during spells of hot weather. Mist greenhouse plants to keep the mite at bay.

  • September

    Keep picking peppers as soon as they have reached the desired colour. Remove excess foliage that is blocking out sunlight from the developing fruits.

  • October

    Finish picking peppers this month. Lift plants up before the frosts reappear and hang them upside down to encourage the last fruits to ripen.

  • November

    Remove the last plants from the greenhouse to the compost heap. Make sure all traces of root are removed from greenhouse borders.

  • December

    Order in seed catalogues and start planning which plants you would like to grow next season. Be adventurous and try at least one new sweet pepper variety!

Red Spider Mite

Red Spider Mite

Peppers are thankfully fairly trouble-free but the most likely pest to make an appearance is red spider mite. Its name is a little deceptive, as it only turns red at the very end of summer and into autumn – their normal colour is pale green.

Spider mites are sap-suckers that thrive in hot, dry conditions such as those found in greenhouses or polytunnels. Symptoms of infection include a pale mottling on the upper surface of leaves followed by severe infections, leaf drop and tiny webbing between stems. The mites themselves can be found on the under-surface of leaves along with their eggs.

Good hygiene will do a lot to prevent infestations of red spider mite, as will keeping your greenhouse plants well watered so they do not dry out. Good ventilation in hot weather is essential, as is regular misting of plants in high temperatures. If the pests do become a problem then a biological control will provide the most reliable solution. The one to use is Phytoseiulus persimilis and it can be ordered from most mailorder suppliers. It can be applied any time during the greenhouse growing season, but setting it in place early will guarantee a build up of the predators before the mites become too active.

Related Forum Topics

Sweet Peppers: Varieties To Try

  • Corno Rosso

    This Italian favourite is also known as ‘Corno di Torro’, translating to Bull’s Horn, thanks to its shape. The tapering red fruits have a sweet flavour.

  • Goccia D'oro

    Elongated and slightly misshapen fruits make this an unusual but stunning variety that’s perfect for grilling or barbecues.

  • Topepo Rosso

    These squashed-looking peppers are well worth growing thanks to their deep red colour and unrivalled flavour.

  • Eve's Apple

    These small, bright red fruits are just 5x5cm but the plants are prolific croppers and fruit extremely early.

  • Phoebus F1

    Pick this if you want an early-to-mature yellow pepper. The blocky fruits have a thick flesh, making them perfect for stuffing.

  • Alma Paprika

    Exceptionally sweet, thick-walled fruits are formed on this variety. They start off a creamy white colour and ripen to orange then red.

  • Golden Treasure

    Tapering fruits reach up to 23cm long. The skin is very thin and delicate and takes on a beautiful golden hue.

  • Purple Beauty

    An early-ripening variety that forms deep purple peppers. It is resistant to tobacco mosaic virus and is vigorous too.

  • Bell Boy F1

    A well-established, highly productive pepper. Sweet, flavoursome fruits start off green and ripen to red.

  • Biscayne F1

    Known as the ‘frying pepper’ in the US, this versatile pepper can be picked at any stage from pale green through to red.

view all

Ripen Up

Poor summers can significantly reduce the number of peppers achieved per plant but there are a few things you can do to boost both productivity and ensure fruits attain their full colour and potential. The first thing plants require is a constant supply of moisture, so make sure the soil never dries out entirely – a layer of mulch should help to keep water locked in. Of course, wet weather may supply too much of a good thing, so it’s important to make sure that the soil is well drained and never saturated. One way to hedge your bets against a cool summer is to start seedlings off as soon as possible so that they are a good size when they are planted out. Seed may be sown from mid-February.

Plants that are fruiting this month can be encouraged to colour up by removing any excess foliage that is shading the developing fruits. Allowing warm sunlight to reach your peppers will soon encourage them to ripen. Outside plants may be chivvied along by covering them over at night with horticultural fleece to keep them that little bit warmer. Drape it over plants early in the evening, before the heat of the day has fully escaped, and remove covers in the morning to allow sunlight direct entry; this will speed growth rates. If there are a lot of young peppers on each plant then remove some of the smallest ones that are unlikely to swell in time; this will concentrate the plant’s energy into swelling those that are left, ensuring a decent-sized fruit and a rich colour.

Sweet Peppers

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