Sweet peppers and chillies have evolved from the same species, Capsicum annuum. The amount of capsaicin (the chemical that causes hot burning) varies naturally in this species.
Sweet peppers contain none, due to a recessive gene, so they can be eaten easily and in quantity. They are very healthy especially when left to ripen to orange or red. Then the Vitamin C content rises greatly. The flavour also changes: as the pepper colours up the flesh becomes sweeter.
Some sweet peppers have a distinctive long, pointed chilli shape. These are known as ox horn, but most varieties are bell peppers. These are almost rectangular or square in shape. These are the best to grow for the amateur gardener because the flesh is much thicker and sweeter.
Chillies and sweet peppers both grow very well in Mediterranean areas. However Britain’s climate is not warm enough, despite the fact that plant breeders have developed varieties for cooler climates like ours. We have to provide extra warmth: they will not thrive in open gardens.
Sweet peppers are are much easier to grow than chillies because they don’t need as much heat in order to crop. Crunchy sweet peppers can be eaten raw, used in cooking, or frozen if there’s a glut.
When to plant
If you want to try growing them for the first time, buy some ready-grown plants in the spring. However, don’t place them outside until June as they are frost tender.
If you would like the challenge of growing from seed the seeds need to be sown in late-February or early March in warm conditions (roughly 20°C/70°F).
Where to plant
If you intend growing them outside, you will need to plant them in large containers or grow bags in the warmest, brightest position you have. Once in pots, they need careful watering on a daily basis, or use a self-watering system such as Autopot.
The ideal situation is an unheated greenhouse and peppers will happily share with tomatoes. Make sure that the taller tomatoes do not block out light though. Both can be planted in the ground. Keep the greenhouse well-ventilated.
Seedlings can be pricked out into small pots before being transplanted into larger ones containing John Innes no 3.
If you have a small greenhouse you can probably grow several sweet pepper plants. If so, it is worth raising your own plants so that you can select the best varieties.
How to grow
Seeds need to be sown in early March and an electric propagator is a real help for raising seeds that need warmth. I’ve found the Vitopod Electric Propagator is excellent.
Sow the seeds thinly on the surface of the compost, one variety per pot. Usually there are 10 seed per packet.
Cover very finely with sieved compost and place somewhere warm and bright – preferably in an electric propagator.
Germination takes between seven and 10 days.
Once the seedlings develop true leaves (ie more than two) prick them out into three-inch pots of John Innes no 1. Keep them on the dry side: this encourages root development.
Once the roots reach the bottom of the pot, usually after four weeks, pot them into a much larger pot containing John Innes no 3. Then place them in a greenhouse.
Plant them in the ground under glass by mid-May. Or you can keep them in pots and place them outside in early June - after the risk of frost has gone. Standing your pots on feet helps drainage. You can use grow bags too.
Feed pepper plants every two weeks with a tomato fertiliser once the flowers appear.
A good plant will yield about twenty peppers over summer.
The value of F1 Varieties
F1 varieties germinate more strongly and crop more heavily too. It’s worth trying to grow different varieties as maturity dates vary. Different colours and shapes also look good on the plate and in the garden.
‘Gypsy’ F1 AGM
Long, slender sweet pepper that crops earlier than most. Prefers a greenhouse. Fruit turns from yellow, to orange to red and ‘Gypsy’ crops heavily. Resistant to Tobacco Mosaic Virus.
‘Mohawk’ F1 AGM
Small compact sweet pepper (2ft, 60cm) that produces lots of medium-sized yellow fruits that ripen to orange. Ideal for containers.
Open-pollinated variety, but very good. Thick-skinned, blocky sweet peppers that start green and then turn orange. A personal favourite.
A good green blocky pepper that fruits early. The green peppers ripen to red.
‘Diablo’ F1 AGM
A long, green ox-horn pepper that ripens to bright-red. However this long pepper produces fleshy walls.
Did you know?
Sweet peppers come from South America, originally from the area bordering southern Brazil and Bolivia. They’ve been grown in Mexico for 2,500 years and were brought to Europe with Christopher Columbus who introduced them into Spain.