If you have a few favorite pepper plants that you'll be sad to see go once winter arrives, overwintering them provides a convenient way to enjoy these plants for another year. Sometimes, for several more years.
Peppers in their tropical native Latin American environment are perennials, and can live for several to many years. In temperate environments, pepper plants are grown as annuals due to their inability to survive the freezing temperatures of winter. Though, if pepper plants are brought inside for the winter, keeping them alive for the following year isn't difficult to do – even with limited room.
Second year pepper plants are usually highly productive. When moved back outside in spring, they'll usually grow many new branches – transforming the plant into more of a bush and, for many varieties, producing more fruit. Additionally, since overwintered peppers have a head start over seedlings, they'll usually flower and produce fruit earlier in the year.
With autumn, shorter days and falling temperatures cause plant growth, flowering and fruiting to slow. Set fruit will continue to mature and ripen until the first freeze. A hard freeze will kill pepper plants. During autumn, keep an eye on the forecast, watching the evening low temperatures. Prior to the first freeze, you'll want to start the process of winterizing your peppers.
When deciding which plants to bring inside for winter, it's important to overwinter only healthy pepper plants. Weakened plants are more likely to be carriers of diseases (e.g. Mosaic virus) and disease spreading pests (e.g. aphids).
Aphids, in particular, can be problematic with overwintered peppers. To reduce potential pest populations, we leave our plants outside in the cooler temperatures prior to bringing them in. Then, a couple of days before moving inside, we like to apply insecticidal soap as an additional precaution.
For potted pepper plants, simply bringing them inside and placing near an unobstructed south-facing window is all that needs to be done. Pepper plants in the garden can be dug up and placed into an appropriate sized pot. Giving the plant a mild pruning to remove less healthy branches at this point is also a good idea.
Choose a good location for your plants to overwinter. A sunny window promotes a healthier plant that drops fewer leaves, and also makes it more productive and pest resistant. If needed, adding supplemental light with a high quality, full-spectrum LED also helps. Overwintered pepper plants do tend to drop a lot of leaves – especially the first few weeks inside – so you may want to choose an area where a little untidiness is acceptable.
Overwintering pepper plants in size appropriate pots subjects the plants to less stress. Though, doing this takes up a lot of space, and trying to overwinter more than a couple of plants can quickly clutter a house.
To save space and bring more plants inside, we've had good results with re-potting peppers into much smaller 4" pots (8" for large plants). We cut the roots back to make it fit and prune the plant drastically – usually to around 6-8" of the main stem(s) – leaving few, if any, leaves. It looks extreme to remove that much; however, we usually only lose 10-30% of the winterized plants downsized to this extent. Water after transplanting to help them recover.
Placing these into a plastic tub is a great way to easily save 10+ plants. After about a week or two inside, the plant stalks will start to generate new growth. This growth is rapid and tends to attract aphids. Watching plants closely during this rapid growth phase is key.
Depending on the climate, a garage may offer just enough protection to see pepper plants through the winter. Here in Atlanta, a friend of ours found this out by accident when he stored his pepper plant pots in the garage for the winter. In spring, we were surprised to see that some of the plants were still alive. When brought back outside, the plants fully recovered and were productive. We retried this experiment with three jalapenos cut down and moved into 4" pots (see above) – one survived and was a very productive plant the following growing season.
If feasible, a garage isn't a bad option. The plants will lose most of their leaves and go mostly dormant. A small amount of light and water will help to maintain them. Keeping them in a size-appropriate pot reduces stress and improves survival odds. Bringing them outside periodically for a few days at a time, when weather permits, also helps. A benefit of the cooler garage temperatures and nearly dormant plants, is that it isn't a good environment for aphids.
Conversely, if the climate permits, pepper plants can be overwintered outside for everything but the most extreme conditions to induce near-dormancy. We left the plants in their original containers, pruned the weaker branches, and kept them outdoors nearly all winter – only being brought inside a few days at a time during hard freezes. This kept new growth to a minimum and the plants had only mild aphid activity during a couple periods of prolonged indoors time. In spring, the plants were quick to recover.
When wintering inside, caring for pepper plants is straightforward. Keep them in a sunny window and allow the soil's top layer to dry out slightly between watering. Plant pots should have good drainage – drip trays/tubs are needed to catch water run-off. As mentioned, it's normal for overwintered pepper plants to drop a lot of leaves when first brought indoors.
Keep an eye out for aphids – especially toward the tips of branches, near the newest growth. These pests tend to attack weaker/stressed plants, or those with rapid new growth after a major pruning. Indoor aphid issues are best managed when caught early and treated aggressively.
Once the danger of freezing and prolonged periods below 45°F has passed, pepper plants can be brought back outside. If they were moved into smaller containers when brought inside, simply re-pot into an appropriately sized pot, or directly into the garden.
If they're in the same container as the previous growing season, then it's helpful to add a layer of compost, bone meal, and fresh soil to replenish consumed nutrients. Burying part of the stem will not harm the plant.
To minimize sun scalding when bringing plants back outside in spring, it's best to keep them out of direct afternoon sunlight for the first week, then gradually moving them to increasingly more direct and longer sun exposure. If plants experience scalding – leaves turn whitish, wilt and drop-off after a couple of days – don't worry! Overwintered peppers should re-grow new leaves within a week or two – just make sure to keep them watered. We've had this happen to us more than a few times, and have yet to lose a plant because of this.
Many times we'll find the first set or two of flowers are unproductive (dropping off without setting fruit) with overwintered peppers, but afterward, they quickly become productive and start fruiting. Sometimes this lack of productivity can last upwards of a month. This is likely due to daytime/nighttime temperatures not yet being warm enough to support fruiting – in excess of 65-80°F during the day and 55°F at night.
As was done while the plants were indoors for winter, you'll want to continue watching for the Mosaic virus. Quickly discard plants that show the telltale wrinkled, yellow-spotted leaves with abnormally weak new growth.
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