Overwintering your chilli plants
Chilli plants are not annuals. They are in fact short lived perennials which, given the right conditions will live for several years. Plants which have been successfully overwintered will produce pods far earlier in the year and have more vigorous growth than plants grown from seed at the start of the season. Harvests are also better for overwintered plants.
A plant over the winter goes into "hibernation mode". It effectively stops all growth phases and reduces its need for both light and food. For several weeks it can look like it has died. Once conditions improve in the spring, the plant will begin to sprout new growth.
We have been growing chillies commercially for 6 years and as a hobby for around 15. We have found plants overwinter better depending on the species. The only plants which are difficult to overwinter are Capsicum annuum. We have had excellent results from Capsicum pubescens (Rocoto) and baccutum (Aji) and mixed results from Capsicum frutescens and chinense (Hab/Scotch Bonnets/Naga).
The key is overwintering any chilli plants is location and warmth.
If you have chilli plants outside in unheated greenhouses or tunnels, you need to pot them up and bring them in. A plant will not survive outdoors in our british climate when the temperature drops below freezing.
If it is not practical to bring plants inside, try constructing an inner tent within your growing area. Use heavy duty bubblewrap or fleece and raise the plants off the ground onto benches. Use heated mats if possible underneath the pots. On warm days, you can always remove your plants from the tents to "hardy" them up. Make sure to place back on the heated mats as the temperature drops towards late afternoon.
Paraffin heaters can be used to warm unheated tunnels/greenhouses. Just be a bit careful about positioning.
Plants in heated tunnels can be kept in their current position if the temperature is to remain constant all year round.
We find it easiest to bring plants you want to keep indoors. If you keep them on a sunny windowsill, a piece of perspex or thick card behind the plant is a good idea. Keep plants away from cold draughts and not left behind the curtain next to a cold window, away from the central heating in the room.
Firstly, choose only your best looking, most healthiest plants to overwinter.
For plants in pots, we tend to repot, giving the plants new compost. You can use this opportunity to trim the roots if needbe to concentrate the plants energy. This is not mandatory so don't worry if you are unsure how much to trim back.
The general rule of thumb is to cut back any brown stems or leaves. If you have a plant which grows on a single stem, then cutting the stem about 8 inches from the top of the pot is a good idea. By pruning in this way, it means that the plant is not wasting any energy trying to maintain foliage or fruit. Remove any pods off the plants.
We find best success on plants which have a compact, bushy habit. For these varieties, simply remove any brown leaves and then treat it as a houseplant.
We feed our plants over the winter with a diluted seaweed feed every week. We give them a high nitrogen feed to encourage growth towards the latter part of the winter as the temperature starts to rise.
Avoid over watering your chilli plants in winter. 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 mould building up, perhaps every week or so.
Varieties which we have successfully overwintered ...
Annuum species (We do not tend to overwinter annuums as we grow from seed every year).
- Apache, Aurora, Cayenne, Demon, Georgia Flame, Jamaican Red, Numex Twilight, Orozco, Prairie Fire, Red Missile, Riot, Superchilli, Thai Hot
Baccatum - Aji. No problems.
Frutescens - Tabasco, Bangalore Torpedo, Cobra, Firecracker, Naga Jolokia pc-1
Pubescens - Rocoto. No problems. However we have never had any real success with this variety due to poor harvests. We have not grown any Rocoto plants in the last 3 seasons.
Chinense - Patchy. We have had good success overwintering Habanero Fatali, Habanero Condors Beak, Bhut Jolokia, Habanero 7 Pot, Habanero Chocolate. We haven't had such great success with Scotch Bonnets.
Varieties with poor/no overwintering success rates : (basically, tall growing varieties with large fruits)
All sweet peppers, Jalapeno, Numex Big Jim, Anaheim, Bulgarian Carrot, Hungarian Hot Wax, Elephants Trunk, Fresno, Bishops Crown, Padron, Pasilla Bajio, Portugal, Cherry Bomb, Santa Fe Grande.