how to plant, grow & care for chillies
complete growing guide
Chillies can be as good to look at as they are to eat. They can be elegant tabletop companions all summer and autumn, thriving on minimal TLC, or you can keep them in the polytunnel or greenhouse where they will fruit for you all summer long. Keep picking chillies and more flowers and fruits will form. If you are keen to encourage the non-gardeners in your life to take an interest in horticulture, chillies seem to be the way to do it. The variety of shapes, sizes, colours and most importantly potency is enough to intrigue even the most recalcitrant couch potato. We sell them as seeds, seedlings or large plants ready to come into production as soon as they are unpacked.
- Common name Chilli
- Latin name Capsicum
- Type Tender perennial vegetable
- Height & spread 45cm
- TLC rating Medium care
- Aspect Full sun
- Spacing 45cm
- Yield Variable
- Suitable for pots Yes
- Grow in a greenhouse? Yes
how to grow chillies
where to grow chillies
Soil type: Plant your chillies in moist, well-drained soil.
Aspect & Position: Plant in full sun. Chillies in this climate are usually grown in containers in a greenhouse or polytunnel, as this helps develop the intense heat, taste and flavour. If growing outside, your chillies will need a warm, sunny position.
when to plant chillies
You will need to start off your chilli seeds early in the year (February or March) in a warm protected environment. Chilli seedlings can be planted out into the greenhouse or border between May and July.
how to plant chillies
sowing chilli seeds
Start off your chilli seeds in a small pot or seed tray of soil-based seed compost early in the year (February or March) in a warm protected environment. Once they have germinated (the timing of which varies from two to five weeks depending on the variety) let them grow until they have two seed leaves sturdy enough to prick out into individual modules or small 7cm pots.
Pot them on into 9cm pots of soil-based compost once their roots have filled the smaller pots and the plants are around 10cm tall. Keep them growing on in a warm greenhouse or polytunnel or on a sunny windowsill.
planting chilli seedlings
Your seedlings will soon be ready to plant into larger 1 or 2 litre pots or into the greenhouse border. If you have ordered seedlings to be delivered in May these will need to be potted on as they fill the pot, the 2 litre potted plants should be able to stay put. They rarely get enough warmth in the UK to do well outside in the garden, although some varieties are proving capable of coping in a sheltered sunny corner. Smaller decorative varieties that you plan to keep in the house are happy in a 15-20cm terracotta pot and will even overwinter for you if you have enough light.
how to care for chillies
watering & feeding
Water regularly and feed with a general liquid fertiliser, switching to a high potash tomato fertiliser when the first chillies have set. Mist the foliage regularly, especially under cover, with tepid water to improve cropping. How much your chilli plant needs watering will depend on the temperature of your greenhouse.
Pinch out the growing tip when plants reach about 15-20cm high to encourage bushy growth and better cropping. You can also pinch back the side shoots if lots of smaller chillies are desired.
As the chilli plants grow you might need to support them with a cane.
Harvest the chillies as you need them, and if you are struggling to keep up, they dry very well hung on strings in a warm dry shed or greenhouse.
Most varieties will slow down as light levels and warmth decreases in the autumn. Some smaller types can be overwintered indoors, but generally they are treated as an annual in this climate.
- February: Sow chilli seeds indoors.
- Pot on gradually into 2 litre pots.
- Pinch out growing tips.
- Water regularly.
- Feed once first fruits have formed.
- Harvest regularly to keep up production.
- Dry or preserve surplus chillies.
- Overwinter small decorative varieties in the house.
pests, diseases & common issues
Aphids or greenfly can be a problem for chilli plants as they will suck the sap of the new shoots as the plant develops. Squash them as soon as you see them appear. If the problem persists, spray with SB Plant Invigorator.
As a greenhouse plant, chillies can be susceptible to the sap sucking glasshouse whitefly. This has the double disadvantage of causing sooty moulds which grow on the resulting honeydew excreted by the insects. Good glasshouse hygiene is key to prevent the whitefly overwintering, and biological controls (Encarsia wasps) work well to control numbers before they build up to a major infestation.
Grey mould on chilli plants is caused by moist warm conditions, so make sure you have plenty of ventilation in the greenhouse. Tidy up any affected leaves and fruit to avoid the spores from spreading and clean the greenhouse well each winter.
yellowing of leaves on chillies
This will be a sign of stress due to nutrient or water deficiency. As you are most likely to be growing your chillies in a pot you will need to attend to their every need – they cannot go looking for it in the garden soil. A weekly liquid feed is essential once the nutrients in the compost have all been used up (after around a month). This practice should also ensure that the plant is getting enough to drink, but always check the weight of the pot before you water, as their need for moisture is very dependent on weather conditions.
chilli plant leaves curling
Leaves will curl if a chilli is in need of water or indeed it has been overwatered, so make sure you get it just right. Insect damage might also be a cause so check underneath the leaves for aphids or whitefly. Some insects will introduce a virus which can cause leaf curl so isolate the affected plant for a while to avoid transmission.
chilli plant not flowering
This is usually caused by either low temperatures or over feeding with nitrogen-based fertiliser. Give just enough to keep the leaves looking healthy without getting too luxuriant. As soon as you see the buds forming switch to a potash liquid feed (tomato food) to ensure the plant switches to fruit production.
chilli plant flowering but not fruiting
There can be several reasons for this. Insufficient warmth might be one, if the temperature is dropping below 15 degrees at night, and not reaching 25 during the day. Chillies are generally self-fertile, but if there is very little air movement in the glasshouse they might struggle, so you can help by brushing gently over the flowers with a feather duster, or misting with water during hot dry conditions.
chilli plant flowers falling off
This is often caused by too much heat, so it may be that your greenhouse is reaching more than 35 degrees and could do with some shading at the height of summer.
chilli plant wilting
This could either be lack of water, or possibly root damage, caused by vine weevils in the pot. If the plant does not revive after a drink turn it out of its pot and check for large white grubs on the roots – these will need to be destroyed and the compost thrown away. Scrub out the pot in case of eggs and then replant the chilli in fresh compost.
what is eating my chilli plant leaves?
There are very few animals that would attack a chilli plant, so it is most likely insects such as the aphids above, or slugs and snails will have a go at young seedlings before they get their spicy defences fully engaged.
frequently asked questions
how often to water chilli plants?
This very much depends on the temperature of your greenhouse. The best guide is the weight of the pot compared to a pot of nicely moist compost. Obviously, you need to allow for the weight of the plant, but if the plastic pot feels lighter than your control one you know it is in need of a drink. If it is in a terracotta pot you can tell if it sounds hollow when you tap it, but that is whole other skill set to acquire. Usually, it is better to under-water than over, so watch for a very slight wilt in the leaves and water in the cool of the morning or evening.
how long does a chilli plant take to grow?
If you sow your seeds in February you should be picking chillies by July, so that is six months given warm sunny conditions. Some varieties are quicker than that, but it very much depends on weather conditions.
can you eat chilli plant leaves?
Although chillies are in the solanum family (along with tomatoes, potatoes and deadly nightshade), the leaves are apparently edible, as long as they are cooked first. I have yet to try it myself!
how do you gauge the heat of a chilli?
The Scovile scale was devised over a century ago to measure the relative pungency of different varieties of capsicum. The methodology of testing has been updated, but the scale remains the same, ranging from 0 (for a sweet pepper) to 3 million for the hottest chillies, used mainly to manufacture pepper spray. Most culinary chillies score between 5,000 (Hungarian Hot Wax) to 100,000 (Habanero), and the number can be mentioned on the seed packet or plant label. But it is still a bit of a lottery as the heat also depends on the amount of sunshine and the watering regime during cultivation. The drier you grow your chillies, the hotter they get!
how long do chilli plants live?
In their native South America chillies are perennial. Some varieties will reliably overwinter in the UK, but usually light levels are so low you are better off starting with fresh seedlings each year.
do chilli plants die after fruiting?
No, they should continue to flower and fruit as long as you pick them until the weather gets too cold and dark for them to keep going.
should I trim my chilli plant?
If you have managed to overwinter your chilli plant it might well need some dead leaves and twigs removing in the spring to encourage it to shoot again. Generally though, apart from pinching out in the early stages to get a bushy plant, they should not need any pruning.
how many times does a chilli plant fruit?
A healthy plant will produce chillies continuously throughout the summer – the more you pick the more you get. Often far more than you can possibly eat, so drying, pickling or turning into hot sauce is definitely a possibility.