If you can make your undercover growing area warm enough for winter, overwintering chili plants might be a fun idea to think about.
Gardeners in the UK will often focus on growing crops as annuals during the summer months. But if you do things the right way, you might be able to grow your own food all year, not just in the summer.
If you have a polytunnel or other covered area that doesn’t get frost, you might be able to grow warm-season plants that are usually only grown once in the British Isles and bear fruit the following year. This is what overwintering chilli plants is all about. What are polytunnels? In this article: [.
For chilli pepper growers in temperate climates, the onset of winter brings an important question – can chilli plants survive frigid winter conditions? The short answer is yes, with proper overwintering care, chilli plants can endure and even continue producing through the winter months.
Chillies thrive in tropical environments and their ideal temperature range is 70-80°F. However, with protection from frost and extreme cold, most chilli varieties can survive and bounce back vigorously in spring. Here is a comprehensive guide to overwintering chilli plants and ensuring they make it through winter to reward you with an abundant harvest.
Are Chilli Plants Cold Hardy?
Chilli peppers are not naturally cold hardy. Native to Central and South America, they prefer steamy conditions and lots of sunshine. While they can tolerate some cool weather, most chilli varieties will suffer damage and decline below 50°F. Light frost is devastating and temperatures below freezing can kill the plant entirely.
A few very hardy pepper cultivars can withstand light frosts down to 30-32°F Andean landrace peppers like the Bolivian Rainbow are more adapted to high elevations and cool mountain conditions. But even these will need winter protection in harsher climates.
For most backyard growers, overwintering chilli plants indoors is the only reliable method for getting them through freezing winters unscathed. With the right care, the plants will survive and return vigorously the following season.
How Cold is Too Cold for Chilli Plants?
Chilli peppers thrive in daytime temperatures of 70-90°F and 60-70°F at night. Cooler fall weather below 50°F causes plants to slow growth and stop setting fruit. When night temperatures drop below 45°F, leaves may yellow and plants decline.
Here are the critical climate thresholds for chilli plants:
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45-50°F – Plants stop fruiting and grow very slowly. Provide frost protection.
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40°F – Leaves discolor and plants appear stressed. Move plants indoors.
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32°F – Damage occurs. Plants with prior cold stress may die.
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25-30°F – Plant death likely, except for some Andean varieties.
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< 25°F – Almost certain death of plant from frost damage.
To safely overwinter chilli plants, they will need an environment above 45°F for the winter season.
Overwintering Chilli Peppers Indoors
Since most backyard chilli growers lack a heated greenhouse, overwintering indoor is the best option. Here are some tips:
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Timing – Bring plants inside before night temperatures drop below 45°F.
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Pruning – Cut plants back by 1/3 to 1/2 to reduce resources required.
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Soil – Dry out soil before moving inside to prevent mold.
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Sunlight – Place in south-facing window or use grow lights for 12-14 hours daily.
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Temperature – Maintain temps between 55-70°F for growth, 45-55°F for dormancy.
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Water – Water lightly when top few inches of soil are dry.
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Fertilizer – Use half strength fertilizer monthly if actively growing. None if dormant.
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Pests – Check frequently for aphids, mites, whiteflies which thrive indoors.
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Air Circulation – Ensure good air movement to prevent disease.
Follow these tips diligently and your overwintered chilli plants will thrive until spring returns!
Where to Overwinter Chilli Plants
Chilli plants need bright light through the winter, so a south-facing window is ideal. For even better results, use grow lights to supplement natural light. Basements and garages are too dark and cool. Here are some good overwintering spots:
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South-facing sunroom – Warm and bright location perfect for overwintering.
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Indoor greenhouse – Maintains needed temperatures and humidity.
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Under plant grow lights – Provides 12-14 hours of daily light.
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Heated garage – Insulate garage and add space heater to keep above 45°F.
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Kitchen window – Provides warmth and sunlight but may be too dry.
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Spare bedroom – Use grow lights to supplement weaker winter sunlight.
Choose your overwintering spot based on the conditions you can provide. The warmer and brighter, the better!
Caring for Overwintered Chilli Plants
Chilli plants require some adjusted care over the winter:
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Watering – Don’t overwater! Check soil and water only when top few inches are dry.
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Temperature – Maintain 55-70°F for active growth, 45-55°F for dormancy.
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Light – Rotate plants in sunny windows to equalize light exposure.
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Pruning – Remove dead leaves/stems. Don’t heavily prune dormant plants.
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Fertilizer – Use half strength fertilizer monthly if actively growing. None needed for dormant plants.
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Pests – Monitor closely for pests like whiteflies and spider mites that thrive indoors.
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Cleaning – Dust leaves and keep nearby area clean to prevent disease.
Adjust care based on whether your plants are dormant or actively growing over the winter. The goal is to meet their basic needs until spring.
Common Chilli Overwintering Problems
With the right conditions, overwintering chilli plants is straightforward. But issues can occur if care isn’t adjusted properly:
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Leggy growth – Insufficient light leads to weak, elongated growth. Supplement with grow lights.
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Leaf drop – Normal for dormant periods. But can indicate overwatering, pests, or root rot.
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Failure to thrive – Due to insufficient light, water, nutrients, or heat. Assess conditions.
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Pests – Spider mites, aphids, and whiteflies thrive on indoor plants. Treat promptly.
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Diseases – Bacteria and fungi spread easily indoors. Isolate and discard diseased plants.
Monitor plants closely and fix issues right away before they worsen. With attentive care, you can avoid these common overwintering problems.
Caring for Chilli Plants in Early Spring
Once spring arrives, acclimate chilli plants to the outdoors:
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Hardening off – Gradually expose plants to sun/wind over 2-3 weeks before transplanting.
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Transplanting – Transplant to larger containers or garden after danger of frost passes.
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Fertilizing – Begin regular fertilizing after transplanting. Use a balanced liquid fertilizer.
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Pruning – Prune leggy growth and shape plants. Cut back dormant plants by 1/3 to encourage bushy regrowth.
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Watering – Water more frequently as plants resume active growth.
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Mulching – Apply mulch to conserve soil moisture and suppress weeds.
With proper hardening off and care, your overwintered chilli plants will take off and reward you with earlier harvests and heavier yields!
Will Potted Chilli Plants Survive Winter Outdoors?
Leaving potted chilli plants outdoors over winter is very risky, even if temporarily moved to a sheltered area. Most potted chillies lack sufficient cold hardiness to survive winter:
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Exposure kills root systems – Above ground portions can be protected, but roots sitting on cold ground are damaged.
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Soil moisture is hard to control – Excess moisture damages dormant roots. Pots are prone to overwatering.
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Smaller root zones are more vulnerable – Less insulation and reserves compared to garden plants.
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Sudden cold snaps cause devastating damage – Brief plunges below 25°F can kill uncovered plants.
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Harsh winds increase cold damage – Wind chill intensifies the effects of cold on above ground and below ground plant tissues.
While a few very hardy varieties in optimal microclimates may make it through milder winters outside, it is not worth the risk for most potted chilli plants. Overwinter them indoors for best results.
Hardy Chilli Varieties That Can Handle Some Cold
Most popular chilli cultivars are not cold tolerant. But there are some naturally hardier varieties:
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Ancho – Withstands light frost. Originates from Mexican highlands.
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Jalapeño – One of the most cold tolerant varieties. Needs protection below 30°F.
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Anaheim – Tolerates cool coastal climates better than other hot peppers.
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Serrano – Moderately cold hardy. Grows well in Southern California winter.
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Poblano – Handles cooler high altitude conditions well. Not frost hardy though.
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Bolivian Rainbow – Extremely cold tolerant landrace pepper. Can withstand light
Overwintering Chilli Plants in Pots
Overwintering your chili plants in pots gives you the freedom to move them around and keep them warm enough during the winter. Here’s a step-by-step guide to effectively overwinter your chilli plants:
- Leave Outside as Long as Possible: Put your chili plants outside in a safe place until the temperatures start to drop regularly.
- Moving Indoors: When it gets too cold outside, usually when the temperature stays below 10 °C for a long time, it’s time to bring your plants inside. Choose a room that is cool, well-lit, and always between 10 and 15 °C. To avoid frost damage, it’s very important that the temperature doesn’t drop below 10 °C.
- During the winter, if you keep your chili plants in a cooler place, they will go into a dormant phase. They won’t make fruit, but they will save energy to get ready for the next growing season.
- Warm Location Choice: If you’d rather, you can also keep your chillies over the winter in a warmer place, like a sunny conservatory, a heated greenhouse, or next to a sunny window. Here, the temperatures should not exceed 20 °C. Because it is warmer, the plants may be able to keep flowering and maybe even produce fruit all winter. But keep in mind that higher temperatures inside can make pests like spider mites more likely to appear.
- Light Needs: Making sure the plant has consistent light is important because not enough light can kill it. A brightly lit spot without direct harsh sunlight is ideal.
Providing Conditions to Overwinter Chilli Plants
Making sure that overwintering chili plants in the UK have the right conditions is the most important part of this process and will determine how well your efforts go.
Temperatures are the main consideration. To overwinter chili plants successfully, you need to keep the temperature between 5 and 12 degrees throughout the winter and make sure there are no frosts.
These conditions can be maintained within a cooler area inside your home, such as a porch or conservatory. You might also be able to keep these conditions in a greenhouse or polytunnel, but if you are working in a room that isn’t heated, you will almost certainly need to add more protection.
Most who are overwintering chilli plants in a polytunnel greenhouse will do so within a heated propagator. But this may be a challenge if you do not have power to this area.
If you keep the area warm in other ways, you might also be able to keep chili plants over the winter “off grid.” For instance, you could make a hot bed in your outdoor growing area and cover it with a mini polytunnel or cloche to keep the heat in.
Overwintering Peppers – Grow This Year’s Peppers again NEXT YEAR!
FAQ
Can chilli plants be kept over winter?
Do chili pepper plants come back every year?
How cold is too cold for chilies?
How many years will a chilli plant last?