Improve Your Harvest by Overwintering Peppers

18 October 2018, written by Benedict Vanheems

Sometimes you can’t help but be a little boastful. So if you’ll indulge me for just a moment, I’d like to share my extraordinary run with this year’s chilli peppers.

They were sown about a month before my last frost date to germinate on an indoor windowsill. I didn’t bother with a propagator but I did do the old clear polythene-bag-over-the-pot trick to keep humidity up. The seedlings were slow to germinate, I’ll admit, but once they (finally!) appeared I moved them on into the greenhouse, which by then was warming up nicely. Periodic potting-on kept seedlings and then young plants growing steadily. And since the second half of summer they’ve been yielding chilli pepper after chilli pepper – after chilli pepper!

Pepper seedlings growing steadily on the windowsill

Moving Peppers Indoors for Winter

Peppers of all types are grown as annuals by most gardeners: sown, grown, picked, then condemned to the compost heap at the end of the season. Yet these hard-working plants are perennials that, given the right conditions, will happily overwinter to next year.

Why bother? Because coaxing peppers to keep going for another year gives you an instant head start on the new growing season, shortening the time to fruit production, extending the picking period and giving you an overall heavier harvest. Sounds good to me!

Overwintering peppers can help extend your picking period

To succeed you need to start with healthy plants, be able to offer your peppers a frost-free spot and keep a constantly searching eye out for their nemesis, the aphid. My chilli peppers have done me proud, and seeing as I have windowsill space it makes sense to give overwintering a go.

Preparing Peppers for Overwintering

It’s best to start with peppers that are already growing in pots. This avoids any unnecessary root disturbance, reducing the risk of failure. That said, if you have strong, healthy plants growing in the ground try digging them up with as much of their original rootball as possible, then pot them into large containers with fresh potting mix fed in around the sides. You will need to reduce the top growth by half to three-quarters to allow for the inevitable loss of roots, but with luck you should be successful.

Container-grown peppers may be pruned to fit the space you have to overwinter them. Make each cut just above a bud and use sharp, clean secateurs. As autumn progresses the stems are likely to die back further. This is absolutely normal – no need to panic! Simply prune back to where the stems are green. Any remaining leaves may turn yellow and drop off too, which is, again, completely normal; some plants will sit through the winter leafless, but will burst into growth again in the spring.

Prune container-grown peppers to a manageable size before bringing them indoors

Temperature, Light and Water Needs

Overwintered peppers need to be kept somewhere that remains comfortably above freezing. In most cases an indoor windowsill, away from heat sources, is just fine. A conservatory would also work well.

Light levels are already low over winter but indoors they’re even lower, so place your peppers on the sunniest windowsill you can find. Again, a conservatory would be ideal given the generally superior quality of light found there.

Keep plants barely moist. The potting mix should be left to get almost dry before watering. You will find you need to water very infrequently as the plants begin to shut down in the lower light levels. Allow plants to soak up the moisture of each watering, but then make sure any excess moisture drains freely away from the base of pots so the roots are never sitting in water.

Aphids are a problem indoors and it’s more likely than not that your overwintered peppers will play host to them. Don’t worry, just clear them off the plant every time they resurface, using a damp cloth to squish and wipe them clear, or by spraying with water.

Resurrecting Overwintered Peppers

About a month and a half before your last frost date, re-pot peppers into fresh multipurpose compost mixed with a little organic general-purpose fertiliser to give plants a boost as they start into growth. Scrape away about 3-5cm (1-2in) of the old growing medium from right around the rootball then re-pot into the same container, or a slightly bigger one, with the fresh compost. Once you notice the first signs of regrowth begin watering more often. Plants can go out into a greenhouse or polytunnel a week or two before the last frost date. You can always bring plants back indoors if an unusually cold night is forecast.

Move overwintered peppers back outside in the Spring

With improved light levels and rising temperatures it won’t be long before the leaves come thicker and faster and new branches develop. Once plants have begun to produce flower buds it’s time to begin feeding the peppers once more, with a liquid feed that’s high in potassium to encourage flowering and fruiting. If you’ve done it right, you should get your first fruits a full month ahead of plants sown that spring. Good luck!