Overwintering simply describes the process of keeping your plants alive thoroughout the winter. Doing so means that next year you will not have to just rely on plants you have raised from seed in the spring.
Most people wrongly believe that chilli plants are annuals and will always die off during winter. This is wrong – with the right treatment it is easily possible to keep your chilli plants going for many years.
Not only is it rewarding to see your plants burst back into life in the spring but it also means you can expect to be picking chillies much earlier from over winterd plants than plants raised from seed.
Why overwinter your chilli plants?
If you can make your plants survive over winter they will have a massive head start over any plants you try and grow from seed. The main advantage will be the root structures will already be large and developed. This will mean they will generally produce much higher yields of fruit, and fruit for longer in subsequent years. This can be particularly useful for varieties such as naga or habanero that can have a very short fruiting season in their first years.
Another great reason to overwinter your chillie plants is that it can be a great challenge and provide you with some good entertainment in the dead of winter when there is little else to do in the garden. If like most chillie growers you are impatient for your plants to grow in spring you’ll also have the advantage of getting some good early growth in.
How does overwintering work?
Much like when and animal hibernates a plant that is overwintered acts almost the same. The plant reacts to the lower temperatures and low light levels of winter and effectively shuts down all growth phases, so much so that all signs of life disappear. For a long period of time the plant will look as if it has died. This process helps the plant protect itself from its new cold and dark environment and reduces it’s need for light and food. Once conditions improve the following spring the hibernation will reverse and the plant should sprout new growth again.
The above process is how chilli plants react in warmer climates such as Asia and South America however the colder winters we experience in Europe and North America will more often than not kill the plants. To ensure your plants survive the colder winter and come back to life next spring stronger than ever there are a few simple steps you will need to take.
How to overwinter your chilli plants
1. Not all your plants will make it though the winter. Assuming you are like most people available space (away from frosts) such as in the greenhouse or conservatory or a sunny windowsill will be limited so only choose your best looking, healthiest chilli plants to overwinter.
Of the 5 main species of chilli pubescens tend to fare better however all will work if you treat them well and have a bit of luck. As a rule it is best to over winter plants that take longer to fruit such as habaneros.
2. As summer is coming to an end give each plant a careful check over looking out for any signs of disease or pests. If you find either seperate out the good plants from the bad to avoid any further infestations. Only attempt to overwinter your strongest looking plants as weaker plants will have a much lower survival rate. When night time temperatures fall (to around 10 degrees) you should start thinking about preparing your plants for the winter. In the UK this tends to be about the end of October.
3. Be sure to remove any chillies from your plants as you do not want to waste any! If the plants have unripe fruit then you can try and ripen them off the plant.
4. Pruning. Having just spent a year looking after and nurturing your chillie plants it can seem particularly cruel to cut them back so severley. However to increase the chance of survival it is best to give your plants a sever pruning back as winter closes in. Prune back each plant so you only leave about 10-15cm of the main stem. This seems extremely harsh however it ensures your chilli plant will not waste any energy trying to maintain foliage or fruit instead saving it for it’s battle for survival over the winter.
5. Repotting. After trimming back your chilli plants it can be a good idea to remove them from the pot, shake off the root ball slightly and repot using some fresh compost. This will help the plant grow back healthier in the spring. If your plants are in large pots (bigger than 30cm) you can also trim back the roots slightly and pot into a smaller pot to help concentrate the energy.
6. As you will have learned already chillie plants like heat. You will increase their chances of survival massively if you move the plants inside a greenhouse (if they are not in one already). This will help keep the roots warm and protect them from frost. In fact if you can move them inside the house as the average temperature will be much higher. A sunny windowsill is ideal.
7. As is the case during the summer it is best to avoid over watering your chillie plants in winter. Remember that because of the lower temperatures it will take much longer for them to use the water you give them. As a result water much less frequently than in the summer to avoid mold building up. Check them once a week and only water if necessary, maybe as little as every 2-3 weeks.
8. Be patient. When spring come round it can take a few weeks before the plants spring back into life and new growth forms. However when they do they will already have a nice big strong root structure formed that will enable them to fruit long before any plants you are starting from seed.