Help, holes in my peppers!
QI grew sweet and chilli peppers for the first time this summer, but the plants produced few fruits that didn’t reach full size. They also had small holes in them. What caused this, and how can I grow them better next year?
Chris Nightingale, Hartlepool, County Durham
AThis sounds like the work of tomato moth caterpillars, which (despite the name) seem to find both sweet and chilli peppers tastier. Eggs are laid on leaf undersides and feeding caterpillars cause white papery patches. The growing larvae disperse and often make holes to enter and feed inside developing or ripe fruits. When fully grown, they pupate just below the soil surface or in other debris.
Watch for early leaf damage and young caterpillars to squish before they do more harm. I welcome birds into my greenhouse – and regular visits by wrens, robins and hedge sparrows help to reduce pest numbers. A pheromone trap will lure and hold male moths, to reduce mating and egg laying. If the problem cause white papery patches on leaves so keep an eye out for early leaf damage keeps recurring, you can try spraying on a biological control nematode that targets caterpillars.
Another solution is to grow plants laden with so many fruits that losing a few won’t be noticed. To reach a good size, peppers need a long growing season and are usually sown in February or March. Getting them to germinate in a propagating case or on a warm windowsill at around 65ºF (18ºC) is easy enough. Seedlings are transplanted one per 3½in (9cm) pot and need bright, warm conditions to grow on. They can remain on the windowsill while small but are then best grown in a greenhouse, polytunnel or large cloche.
Plant three to a growing bag or pot on to 5-6in (13-15cm) pots. Those with good, early vigour can move to larger pots, up to 9in (23cm) wide, but don’t let small plants wallow in too much compost from midsummer. Feed established plants initially with a well-balanced liquid feed and then a high-potash one for good flowering and fruiting. Larger plants may require staking.