Chilly outside, chillies inside

We've already had the first frost in London and there's more sub-zero nights on the way, according to the weather forecast. Time to bring in the rest of the plants. Most of my spice plants – cardamom, turmeric, ginger and pandan - are already safely indoors, but the chillies and citrus were still out until the weekend.

Chillies will overwinter quite happily, best somewhere with plenty of light, not over-warm, but definitely frost-free. They may well lose many leaves, but you should see new growth in January. And while you won’t get chillies developing all year round you will get some very early fruits in the next spring. They are however quite short-lived perennials, only lasting 2-3 years in any case. 

Citrus plants, for all that they like the wide variations in temperature - warm days and cool nights - won't stand any frost at all. They need to come indoors and spend winter in a cool place - between 7 and 13 degrees Celsius. They don't like very dry air, and they don't need much in the way of watering over the winter months.

Kaffir lime, ready for clean-up before coming indoors. 

Before the plants come in, however, they will need to be cleaned up. With chillies especially, you'll often find an infestation of aphids takes hold about three weeks or so after bringing them in. Aphids are perhaps easier to prevent than cure. On inspection, your citrus plants too may be harbouring pests that need to be removed before relocating indoors. Mine tend to be susceptible to scale, which can be rubbed off or scrubbed away with an old toothbrush. Check particularly on the underside of leaves alongside the central vein.

Left, scale insects lurking on the leaves; right, snail leaves its last trail on this particular plant.

I often find tiny snails hiding in the foliage of both chillies and citrus: dispose of these so they don't get to spend all winter chomping away on your leaves.

So the plants all get a bit of a spruce-up before being allowed to cross the threshold. First I remove any tatty, holey, yellowing leaves, any withered or brown stems, old flowerheads, etc. Any weeds that have seeded in the pots (perish the thought!) are removed.

Cleaning up the smaller plants is easily done by dunking them in soapy water, I'm indebted to citrus specialist Plants4Presents for this tip: it's a lot less fiddly than going over the whole plant with a handheld spray, sponge and toothbrush. Tie a clear plastic bag around the pot and the base of the main stem, fill a sink (or a bath if you have several plants) with soapy water (lukewarm water plus detergent to the same dilution as if you were washing up will do fine), up-end the plant and dunk it, leaves first, into the sink (bath). Count to five and haul it out again. Leave it to drain, right way up, before putting it in its final overwintering place. This should stop any aphids lurking in the leaves in their tracks. If you get any further infestations during the winter, repeat the process.