Growing Chillies in the Greenhouse Advice
Written by John Harrison on 19th Jan 2016.
Choose Your Chilli Varieties Carefully
We're all tempted to grow the extremes, the biggest or most flavourful and with chilli peppers, the hottest. But do think it through, there's little point in putting a lot of effort into growing a pepper that is so hot you can't actually use it. A milder variety means you can add flavour as well as heat to a dish where even one of the super-hot chillies can be too hot to taste and just makes the dish hot.
Long Growing Season
The secret to a good crop of chillies is a long, hot growing season. This is why they're usually best grown in a greenhouse. You can grow them outdoors but the British summer is variable to put it mildly and a glass or polycarbonate greenhouse is much more reliable.
When and How to Sow Chilli Peppers
Start your chillies by sowing in early February in a heated propagator set to 20 to 24 degrees C. Ideally in the greenhouse but if you don't have power to the greenhouse, start them indoors on a sunny, south-facing window sill.
Sow your seeds individually in 2.5 cm pots or 15 to a tray modules filled with a multi-purpose compost mixed with a fifth by volume of perlite or vermiculite. Just drop a seed on the surface and cover with a little perlite, then water in gently with warm (20 to 24 degrees C) using a very fine rose on the can.
Handling Small Seeds
Tip: sowing small seeds individually can be difficult. Use a plastic dibber or even a pencil with a wet end to pick them up. I just lick the pencil but it's probably bad for you so I'd best not suggest it!
Growing On
Germination is usually a week to 10 days, wait until the seedling has small leaves and then transplant into 7.5 cm or 10 cm pots of multi-purpose compost.
Water in using water at the propagator temperature to avoid shocking the seedlings. Start gradually reducing the temperature, hardening off the seedlings to the greenhouse temperature which ideally will be around 15 degrees C or more.
After a week, keep checking the bottom of the pot and as soon as you see roots starting to poke through the holes in the base, transplant again into their final place. I prefer 20 cm or 24 cm pots but you can plant two to a standard grow-bag if you prefer.
Cultivation
Support the plant with two or three short canes in the pot or bag to stop them falling over, especially when they are laden with fruits later. Pinch out the main stem when it is about 30 to 40 cm high to encourage lots of side shoots to develop.
Water as required but avoid waterlogging.
After six weeks, or when flowers appear if sooner, feed with a general purpose fertiliser such as Miracle Gro and thereafter feed with a tomato feed every two weeks. If the plant loses condition and especially if the leaves yellow, revert to a general purpose liquid fertiliser for a feed or two.
Harvesting
Once the fruits mature and colour, snip them off with secateurs or sharp scissors, leaving the immature fruits to develop.
Pests and Problems
So long as the plants are warm enough, fed and watered they are remarkably easy to grow and trouble free.
Whitefly & Aphids
Sometimes they can be bothered by whitefly, most usually caught from other plants in the greenhouse like tomatoes and aubergines. Yellow sticky cards will control minor infestations but for serious aphid problems consider a spray (approved for food crops) or a biological control – Encarsia formosa.
How to Save Chilli Seed for Next Year
Saving chilli seeds is a brilliant way to keep your favourite varieties going year after year. It's quite simple, really. First, I'll scoop out the seeds from a fully ripe chilli and give them a good rinse under the tap to remove any bits of flesh. Then, I spread them out on a couple of layers of kitchen paper to dry. If I'm feeling organised, I'll jot down the variety name on the paper too - it's amazing how easy it is to forget which is which!
Once they're bone dry (usually takes a couple of days), I simply fold up the paper and pop it in a labelled envelope. Then it's into a cool, dark spot until next February when the growing cycle starts all over again. It's a lovely way to connect this year's harvest with next year's plants.
How to Preserve Chillies
When you've got a bumper crop of chillies, preserving them is a fantastic way to enjoy your harvest all year round. I'm particularly fond of drying and freezing - both methods are straightforward and give you plenty of options for using your chillies later on.
How to Dry Chillies
Air drying chillies is not only practical, but it also adds a lovely rustic touch to your kitchen or greenhouse. Here's how I do it:
- Pick chillies with a 2-3cm stem attached
- Bunch them together and tie with string
- Hang from a curtain pole or greenhouse eaves
- Leave for a few weeks until completely dry
If you're in a cooler climate, you might find oven drying works better. Just lay them out on a baking tray and pop them in at the lowest setting until they're crisp.
How to Freeze Chillies
Freezing chillies is my go-to method when I'm short on time. They freeze beautifully and retain their flavour wonderfully. Simply bag them up whole and pop them in the freezer. When you need one, just grate it frozen straight into your cooking - it works a treat in stir-fries or over a steaming bowl of pasta.
| Preservation Method | Pros | Cons |
|---|---|---|
| Air Drying | Decorative, long-lasting | Takes time, needs warm climate |
| Oven Drying | Quick, works in any climate | Uses energy, need to monitor closely |
| Freezing | Quick, retains flavour well | Requires freezer space |
FAQ
Do chillies grow well in a greenhouse?
Absolutely! Chillies love the warm, protected environment of a greenhouse. It's like giving them a little slice of their native tropical climate. In fact, some of the hotter varieties really thrive in greenhouse conditions.
How often do you water chilli plants in a greenhouse?
I find chilli plants in a greenhouse usually need watering every couple of days. But always check the soil first - if it's dry to the touch, it's time for a drink. Remember, it's better to water deeply less often than to give frequent light sprinkles.
Can you grow chilli plants indoors all year round?
You certainly can! With a sunny windowsill and a bit of care, chilli plants can be happy houseplants. They might not be as productive as outdoor or greenhouse plants, but they'll still give you a nice crop and look rather lovely too.
How long does it take for a chilli plant to grow?
From seed to first harvest, you're looking at about 3-4 months for most varieties. But don't worry, once they start fruiting, they'll keep going for months. It's a bit of a wait, but well worth it when those first chillies start to ripen!
Whether you're saving seeds, drying chillies, or freezing your harvest, there's something deeply satisfying about making the most of your chilli crop. It's a wonderful way to extend the joys of the growing season well into the winter months.
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