Chillies (Hot Peppers)

♦ Lovers of chillies have plenty to choose from and in this article we look at ways to grow your favourites. Whatever the situation, there’s a chilli or Capsicum to suit everyone’s tastes because there are well over a thousand varieties to choose from.

Introduction To Chillis

We tend to think of these South American beauties as too hot to grow in slightly colder climates but they are ideal for the greenhouse if not the patio. Of course you can grow fruity and mild sweet pepper types if the Carolina Reaper or even the Naga, one of the world’s hottest chillis is too much to handle let alone taste!

Chillies are simple to grow, but some varieties may need a little more persuasion than others to get started.

They are also prolific fruiters and there is a great variety of fruit depending on the level of culinary heat required, their luminous colour and varied flavour. It’s one reason why I put peppers at the top of the seed list for my first sowings in winter. It may be cold outside but there is this one fruit which will tantalise the tastebuds!

Chillies can be preserved in numerous ways:- drying, freezing  and turning into jams, jellies, sauces or pickles, so the beautiful little fruits are the ideal no-waste crop.

History Of Growing Chilli

We know the ancient Mayans and then Incas who came after were growing chillis back about 7,000 years ago. The plant is found in Mexico and seeds collected from temple sites are around that age. Their popularity with the rest of the world came through the conquistadores. A little like coffee they have become symbolic of hot fiery cuisine in all sorts of countries especially the USA and the Middle and Far East.

Breeding studies to create the myriad varieties started in the early 1900s. In the UK the chilli really never caught on until the 60s when Indian curry houses began to appear. The majority of the breeding programmes were trying to breed ever hotter chili. The ‘Anaheim Chilli’ which is named after the Californian town is probably one of the first of the new breed.

Scoville Units

Wilbur L. Scoville noted pharmacist came up with a heat scale for the chilli in 1912. He gave his name to the unit of heat which is an SHU (Scoville Heat Unit) as its the most reliable and consistently accurate method for monitoring heat. We always think that it’s best to consider what type of heat you require in a chilli before trying to grow it.

A big fat zero is reserved for sweet ball peppers which have no heat at all. As the number increases they get hotter. A chilli of 20,000 SHU is certainly hotter than one of 500 SHU. If it’s a mystery as to what type and level of heat you enjoy, consider that shop-bought Jalapeno chillis are between 2,500 and 5,000 SHUs. A Tabasco chilli which was once part of Beecham Bovril Brands and finds its way into the infamous sauce is between 30,000 and 50,000 units.

 Here we give a guide on the best way to grow these little fiery fruits; they are not a vegetable.

Mexican hot chilli peppers - a colorful mix of habanero, poblano, serrano jalapeno, sweet. Copyright: tonobalaguer / 123RF Stock Photo
Mexican hot chilli peppers – a colorful mix of habanero, poblano, serrano jalapeno, sweet. Copyright: tonobalaguer / 123RF Stock Photo

Sowing Guide To The Best Chillis

Chillies are one of the first crops  we start off in the New Year and they meet that need for gardeners to get going when other veg is on hold for later sowing.

We need as long a growing season as possible to produce these ripe and tasty crops. An early sowing is generally necessary because it is reckoned that the hotter the chilli the sooner the seeds need to be sown. We found this the case when we were growing Nagas and Scotch Bonnets which are some of the hottest around.

The best time I believe to start sowing seed is January and February if you can provide the heat for germination, otherwise its going to be March which works for most varieties.

Sowing is very simple by the way. You need a windowsill propagator which is ideally heated, some pots or plastic modules or a small seed tray and good seed compost like John Innes no. 1 or good quality multipurpose compost.

Begin by getting all the equipment you will need for sowing, as this will save you trying to get the little seeds out of the packet when your hands are covered in soil.

Incidentally, always remember to label your pots if you are sowing different chilli varieties, or lots of types of vegetables. If not, it is extremely difficult to identify what is what when they start to germinate, as they will all look the same at this stage.

Place the seeds on top of the compost in whatever container is preferred. The modules are favoured by us because it is usually one seed per well. They’re also easy to pot on into the next container when you are ready.

If you are using pots then a 9cm (3½in) pot works well if a few seeds are sown together. These are pricked out as and when needed. Leave a small gap between each one to give them adequate space for germination. The spacing between each variety you are growing should be specified on the seed packet. (The same principle would apply to a small seed tray).

Please wear gloves when handling the really hot types as they can burn too – don’t rub eyes or nose even when sowing because they will burn from oleoresin off the seed.

Cover these seeds with some vermiculite or very fine compost if possible to avoid damping off in the cold. Gently firm this down. The seeds should be at a depth just the same as that of the seed itself. This gives them some protection but also allows them to shoot up easily. 


Water those seeds well but gently, using a very fine rose can. You can also place the pots/modules etc. in another larger tray containing water and allow this to soak it up too but be sure not to drown them.

Continue to water them as the soil dries out, but you can be a little more sparing with chilli plants once they are more established – as this stress can mean that the heat is more intense in some cases.

Getting The Seeds To Germinate 

Ideally place these seeds in a propagator for use on a sunny windowsill or in the greenhouse. The greenhouse could be heated if the propagator was not.

If there is no propagator cover your tray/pots with cling film or a glass pane and place somewhere warm. Some growers  prefer an airing cupboard or near to but not on a radiator. Placing them in an airing cupboard works extremely well for me as a way to aid germination. 

Make sure the compost is moist but not soaking when placed where you want (see earlier points about watering).

Try to keep the temperature above 18°C especially in the greenhouse during winter/early spring months, and so providing some bottom heating is ideal, otherwise an indoor room suffices. A few varieties will germinate at temperatures below 18ºC but these varieties are few and far between. The usual germination temperature is traditionally between 18 and 25ºC (65 -77ºF) which is about normal room temperature. Some will actually need 23ºC (73ºF) but these are very rare indeed. Invariably the hotter varieties tend to take longer to germinate.

Feeding should not be needed at this stage.

The seedlings appear about 3 weeks (21 days) later and they should by then be kept warm either in the greenhouse (propagator) or on that sunny windowsill. The seedlings need to be in the light once germination has started. 

Pricking Out

At the first sign of growth, usually a small seedling with two leaves, appears in two to four weeks. 

Move to a warm place out of direct sun, but with plenty of light, such as a south facing windowsill, above that radiator or keep in the heated greenhouse. Some growers prefer the south facing window sill to the greenhouse but this is about economics and keeping a more watchful eye on these seedlings than anything else. The key is keeping warmth going throughout the early cold months.

Water from below to encourage strong roots – capillary matting is ideal. Daily check the soil surface so it keeps just moist.

Let the seedlings grow to about 5cm (2in) in height. Its probably best to take them at this stage out of the seed tray or modules out of the propagator as they can start to get leggy. Keep growing in the same place if you have the room.

The seedlings will need moving on to their own individual pots and then will need regular re-potting from then on. When handling the seedlings, hold them by their leaves, because if the stem is damaged, the plant will not recover.

Remember “Strong Plants Come From Strong Seedlings” !

Growing On

When those seedlings produce their second set of leaves, they will be about 15cm (6in) tall. Carefully transplant to 7cm pots of moist multi-purpose compost. I have found that if you have strong seedlings at this stage, the growing on phase later is so much more straightforward. Check if roots are appearing at the bottom of the pot through holes – that’s a good time to pot on. Try to get the plants to a pot of at least 15cm (6in) diameter. Some varieties will need even bigger pots but it is a case of growing them to a point where the roots are just restricted enough otherwise the fruiting is not so effective.

There are a couple of schools of thought about feeding. One is to feed weekly with a dilute liquid tomato feed (best of all) or some seaweed extract. Make sure the feed is not concentrated – a quarter to half the level is ideal. An alternative second view is to start feeding when the first flowers appear (see below). There is a third school of thought that high potash feeds should be avoided altogether because it produces lanky growth. This last method doesn’t work for me but I do keep the fertiliser quantities on the weak side and I feed when the flowers appear. 

Don’t apply feed to dry plants. Make sure the compost is moist first before then so the plants are turgid and can draw up feed when ready.

Allow plants to reach 12-15cm, then transplant to 12cm pots or have three fit into a 30cm pot. Fill with compost to about 1cm from the top. When plants are about 20cm, support them by gently tying to a cane.

Greenhouse Growing Of Chillies

If growing in the greenhouse, provide good ventilation once temperatures start to rise in April. The crops will need to be moved into a final container if they are grown inside. They can also be planted outside, or in greenhouse borders at this point, depending on where their growing spot for the season will be.

When plants reach 30cm, pinch out growing tips and leading shoots just above the fifth set of leaves to encourage a bushy habit. Don’t worry though if you forget to pinch out, most chilli plants branch at some point. Pot on if necessary and always check daily for aphids. The largest pot needed for any chilli is 3 litres. Any bigger and the plant just produces lost of early root growth and a niggardly amount of top growth.

Grow Bags & Watering

When using grow bags rather than pots say, I let the plant grow to beyond 12 inches and no less. Three plants per bag is enough otherwise they lose vigour. They may be grown in their pots and then placed in the grow bag. The roots soon grow through the drainage holes which anchors the plant into the bag. I don’t use drainage slits as watering is carefully controlled. I understand that watering once a week in the early phase is fine and then about three times a week when the plant is fruiting.

Overwatering Of Chillies

Yellowing leaves and stunted growth are a sign of incorrect watering. Wilted foliage can also be a sign of too little or too much watering. When unsure stay on the dry side.

When flowers appear, help out the bees with some hand pollination by gently dabbing a cotton bud into each flower.  Generally though allow pollinating insects to come to the smallish white flowers by either keeping the greenhouse open or planting with other bee attractors. Use liquid tomato feed when the first flowers show but don’t overdo this otherwise lanky growth ensues.

If watering is poorly managed during the growing season, there is a case of blossom end rot where the fruit will develop brown patches caused by calcium deficiency.


Chillies are ready to pick when they have reached the desired size and colour for the variety you are growing. They should be firm to the touch and have a lovely shine to their bright, smooth skins.

Pick the fruits by snipping the stem just above the fruit.

Snip off first chillies while green to encourage fruiting all season between July and October. You can let the next fruit mature to red for a more rounded flavour and this carries under glass from November through to December.

The chillies may be used straight away, or stored in drying bowls to dry out, as well as being perfect for use in all sorts of jams, chutney and jellies. Many growers dry these chillies and then grind them up to make a powder for use in pimento etc.


Unless heat is provided, chilli plants will not survive the winter although there are some perennial varieties which can be kept lingering on if enough warmth is available. I reduce the size of the plant to about half, keeping enough leaves to allow the bush to photosynthesize. These plants are always overwintered in a warm (heated) greenhouse.

Perennial plants will continue to fruit for five seasons or more but eventually lose vigour.

Varieties To Grow

The Hot Ones!

each year more and more hot chilli varieties appear in the marketplace. It’s a real sore point for anyone who finds the heat too much but there are bragging rights to eating a really hot pepper. There is a variety called ‘Dragon’s Breath’ which has 2.4 million SHUs! The fruit is red/orange and the plant is about 4 feet high.  

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Purchase your chilli seeds here

We review the main ones here:-

cv. Ancho/Poblano. The Poblano is a relatively mild chilli pepper, which when dried, is called an ancho chilli. Ancho/Poblano is one of the most popular chillies grown in Mexico. Poblanos tend to be mild but occasionally one can have overpowering and significant heat. Even those picked from the same plant have been reported to vary in heat intensity. The plant grows to about 60cm in height. The fruits are about 10cm long, and about 5cm wide. An immature poblano is purple / green in colour, but eventually turns a reddy black.

cv. Apache is a well known dwarf chilli that produces good yields on semi-compact plants. The fruits are approx 7cm long and turn from green to red. They are good for use in the kitchen, and have a medium heat. Bred in the UK it is a good choice for growing in containers.

Apache is ideal for patios as well as in the greenhouse and grows to approx. 35cm in height, with prolific fruiting throughout the Summer season. Scoville Rating: 70 – 80,000shu.

cv. Basket Of Fire. Chilli Pepper Basket of Fire is prolific fruiting variety that is breaking new ground, with its semi trailing habit. This unique plant habit makes it a perfect choice for hanging baskets and containers.

cv. Cayenne Gold is a highly productive hybrid orange variety, producing peppers 10-15cm long and 1.5cm wide. This Chilli Pepper is yellow-green with a mild flavour when young, turning orange after a few days to develop the heat.

cv. Cayenne Red is a long, thin bright red chilli which mature from green to red. Exceptional flavour for Far Eastern (Vietnamese, Laos, South Chinese) cuisine.

cv. Cheyenne is a semi-compact chilli pepper, the plant grows to approx. 45cm in height. The fruit is medium sized, around 10-13cm and having orange fruits.

Ideal for patio containers, with prolific fruiting throughout the Summer season. Scoville Heat Rating: 40,000shu.

cv. Demon Red  is ideal for growing in containers and this variety can be used as both an ornamental and edible pepper. The flowers and upward pointing fruits are produced throughout the season.

cv. Fresno  produces a good general purpose chilli that is suitable for use in cooking and salads. The plants are highly productive and may need support. The fruits are conical and about 6cm long.

cv. Fuego  is a hybrid cayenne pepper that keeps its piquancy under cool conditions. The vigorous plants produce long fruit with dark green skin, that turn red when ripe.

cv. Gusto Purple  is a medium hot type, adaptable to a range of growing conditions. Suited to growing inside or outside the yield is high with a good level of holding ability.  

cv. Habenero Red is another very hot chilli. This plant will do best in warmer areas, so is best suited to greenhouse growing in the UK.

The chillies will be red at maturity, the fruits measure upto 4cm long by 2.5cm wide and are produced in abundance.

cv. Heatwave is a fiery mix of hot fruits in shades of red, yellow and orange. A Cayenne type suited to greenhouse culture.

cv. Hot Carrot. The chillies look like a baby carrot but be warned – it lives up to its name and is often very hot. The plants produce a very high yield of bright orange peppers.  

cv. Jalapeno is used in the majority of chilli eating contests, however it actually varies from mild to hot depending on how it was grown and how it was prepared.

The heat is concentrated in the seeds and the veins, so if you want it on the milder end of its scale, remove those parts.

Jalapeno is used in Mexican cooking and is the chilli found on nachos. These plants are tall growers and very productive.

cv. Paper Lantern is an elongated red habanero type with the renowned mouth-blistering heat. The fruits ripen from lime green to bright red and have elongated pendant shaped fruits.

cv. Chilli Ring of Fire are small cane shaped and very hot chilli peppers. They are 10cm long and pointed, ripening from green to red getting hotter as they change colour.

Scoville Rating: 70 – 80,000sco.

Chilli Super Chilli. Chilli Super Chilli is a hybrid small fruited Thai type, with upward pointing fruits. It produces attractive 8cm long fruits on a compact plant, typically 30-45cm high. Fruits turn from green to red overnight !

 The Chilli Scotch Big Sun is a vibrant yellow skinned chilli with very hot globular shaped fruits. They are up to 6.5cm long and 5.5cm diameter which ripen from green, maturing to bright yellow. Easy to pick and extremely productive.

If would like to grow a range of chillis, the South Devon Chilli Farm which is famed in the United Kingdom for growing chillis now offer a growing kit which we would recommend to anyone.

Buy your kit now.

The alternative is to try the chilli kit from pronto seeds which allows you to grow five different varieties.

Buy your kit now.

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