Peppers come in a wide range of sweet and spicy varieties, from bell peppers to the most fiery of chillies. While it is near impossible to grow peppers outside in most of the UK, unless you have a particularly warm and sunny spot in your garden, a polytunnel can be the perfect place to grow these flavoursome crops. The key thing is to start early, as peppers need a long growing season. Starting seeds indoors early in the year will mean that you can harvest peppers of all kinds from your polytunnel in the late summer and autumn and enjoy them in a wide range of different recipes.
Peppers and chillies really do need the heat but since they also take a long time to grow to maturity and fruit, they must be sown indoors in a propagator or warm spot in February or March. Transplant each seedling into a 7-9cm pot when two true leaves have formed and then pot up in mid-late May. You may then continue to grow in containers, or place peppers into the soil in your polytunnel. Bell peppers and other plants which bear heavier fruits may need to be staked and tied in. This will depend on the variety. Pinch out the tops of the pepper plants when they are around 20cm tall to encourage them to bush out.
Pepper plants will need a lot of sun and a soil that stays warm and moist. F1 hybrids allow UK growers to grow these warm weather crops – the down side is that they will not come true from seed and so new pepper seeds will have to be chosen each year and you will not be able to collect your own. There are plenty of different bell peppers and chilli peppers to choose from, depending on what you are looking for.
Organic mulches can help to add fertility and retain soil moisture. Keep your pepper plants well watered and when the first fruits begin to appear, provide the plants with a high potash organic feed. Keep the humidity in the tunnel relatively high and never allow the soil to dry out. A ground cover companion crop like basil can also help to retain soil moisture.
You may begin to pick the fruits as and when they are required. They can be picked when green to prolong and increase the yield or left to mature fully. Fruits will change from green to yellow, sometimes to orange or red as they mature. Leaving fruits to fully mature will reduce the yield but mature fruits can be left on the plants and then dried for use over the winter. Take care when harvesting and preparing strong chillies as they can sting if accidentally rubbed in the eye.