How To Grow Chillies From Seed In The UK  – Complete Guide

If you like spicy food, then growing your own chillies is perfect for you. We will tell you how to grow chillies from seed in the UK.

Many people think that chillies can only be grown in hot countries. After all, they originate from South America.

We love spicy food, so growing our own chillies is a no-brainer really. Although, like many other people, I wasn’t sure at first if we would succeed. 

I was wondering if you can grow chillies in the UK. The answer is, definitely yes. So, in this complete guide you will find out how to grow chillies from seed in the UK.

Grow The Right Chillies For You

habaneros and jalapeños

Before we go into how to grow chillies from seed in the UK, let’s have a look at how to choose the right chilli for you.

Whether you like it really hot or you just want to add a little kick to your food, the right chilli is the key. 

You might have heard of the Scoville Scale. It’s a measure of how hot a chilli is. And it’s a great way to start looking at what chillies you want to grow.

Although we like hot food, we like to grow a variety of mild hot to hot chillies. It’s also good to consider what you want to use your chillies for. 

We grow Jalapeños (mild hot), Cayenne (mild hot to hot) and Habanero (very hot). And I can highly recommend this mix. 

We pickle the Jalapeños and use them on Pizzas, Burgers and Hot Dogs. The Cayenne chillies we use to cook with. We chop and freeze them so we can use them all winter and through spring.

They are also great to make chilli oil, which you can use to cook.

The Habanero chillies we dry and make chilli flakes out of them. We then use them to cook or on Pizza if you want to add some spice.

But the world is your oyster. Because growing chillies from seed means that you have a huge choice of different chilli varieties, from mild to extremely hot.

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How To Grow Chillies From Seed In The UK Step-By-Step

Now that you know about choosing the right chillies for you, let’s get right into the nitty-gritty of how to grow chillies from seed in the UK.

Step 1: Sowing Your Chilli Seeds

sowing chilli seeds

Sow your chilli seeds from January onwards in small pots. Chillies are slow growing, so the earlier you start them the earlier you can harvest them.

By sowing early you can also prolong their cropping season.

Fill small pots with peat-free potting compost, then water the pots. You want the compost to be moist. You can also use seed trays.

Sow two seeds per pot and cover it with a thin layer of moist compost. The same as you would with tomatoes.

Place the pots in a heated propagator or an unheated one on a sunny windowsill. Chilli seeds need at least 18ºC to germinate, but it shouldn’t be any warmer than 25ºC.

Germination time for chilli seeds is between 7 and 10 days, if they have the right conditions.

Keep the compost moist, but don’t be tempted to overwater it as this could cause the seeds to rot.

Once the seeds have germinated, take the seedlings out of the propagator and keep them on warm and sunny windowsill.

Step 2: Growing Your Chilli Seedlings On

Step two of our guide about how to grow chillies from seed in the UK is growing them on.

When your chilli seedlings have their first true leaves (that’s the second set of leaves that will grow), they are ready to be repotted into a bigger pot.

Keep your young chilli plants on the sunny windowsill and water them regularly, but be sure not to overwater them. I wait until the soil is quite dry on the surface.

Because chillies are started early, they need to be transplanted into larger containers until they can be planted in their final place.

Step 3: Planting Them Out

young chilli plants
My young chilli plants are almost ready to plant in the polytunnel.

When it comes to planting your chillies out, you have two option. Either a greenhouse or polytunnel or outdoors in a bed.

Because chillies need a lot of sun, high temperatures and humid conditions, I would recommend to grow them in a greenhouse or polytunnel. This will give you the best results.

A warm conservatory will also do. Another great place to grow chillies is a sunny windowsill in the bathroom. As it will provide the humidity chillies need.

However, if you don’t have either of these, then you can grow them outside.

But if you do, it is important that you choose a sheltered and sunny spot. Growing chillies outside in the UK can be a bit challenging.

A wet summer can reduce the yield you get, because chillies don’t like to be overwatered. And if we get a colder summer, your chillies won’t do as well either.

The wrong conditions can also lead to the chillies not being as hot as you would like them to be.

So I would recommend to grow your chillies in a greenhouse or polytunnel, to ensure you have a good yield.

However, wherever you grow your chillies, make sure you have well draining soil, as this is very important for success. 

Plant your chilli plants in the greenhouse or polytunnel from about the end of April. You want to make sure that the night temperatures don’t get below 10ºC.

If you are growing your chillies outdoor, wait until mid-May to plant them out. You want to make sure that there is no more risk of frost.

Top Tip: Provide taller chillies, such as Jalapeño and Cayenne, with support through a cane.

The first year we grew chillies in our polytunnel, I didn’t stake them, because I didn’t expect them to grow as big as they did.

They struggled once they had lots of chillies on them. So learn from my experience and support your taller chilli plants.

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Step 4: Caring For Your Chillies

caring for your chilli plants

Chillies don’t need much care once they are in their final position.

Pinch out the top once the plants are about 20cm to 30cm (8in to 12in) tall. This will ensure that they produce side shoots, which will give you more chillies.

Water you chilli plants sparingly. It might sound wrong, but chillies need to get stressed to produce hot fruits. I wait until the soils is dried out before watering them.

When you spot the first flowers appearing, start feeding your chillies with a high-potash feed. Tomato feed works well.

We recommend this tomato feed. We have been using it for years and it gives great results, not just for tomatoes but also chillies and potatoes.

Levington Tomorite Concentrated Tomato Food, 2.5 Litre
  • Easy to apply simply mix with water in a watering can according to instructions
  • For tomatoes and flowering pot plants
  • With seaweed extract for maximum growth and better crops

Some people say to feed them once a week. However, I have also read that by not feeding them, and thereby stressing them, they will produce hotter fruits.

I tend to feed them when they start flowering, but only once or twice, after that, I just water them.

My chilli plants have grown really well and produced a lot of chillies. And the Cayenne and Habaneros were very hot.

As chillies love humid conditions, mist them when it’s hot to give them the perfect growing environment.

Make sure you keep your greenhouse of polytunnel well ventilated. Not only will this prevent it getting too hot for your plants, it will also allow pollinators to pollinate your plants.

Step 5: Harvesting Your Chillies

we were amazed how well our chilis did
Some of my Cayenne chillies are ready to harvest.

Now we come to the best part of our guide about how to grow chillies from seed in the UK, harvesting them.

Like sweet peppers, you can eat chillies when they are green or you can let them ripen.

But you should know that the riper they are the hotter they are. So it’s up to you when you pick your chillies. I let them ripen, as we like it hot.

However, letting the chillies ripen also means you will get a smaller yield. But I think it’s worth it for the hotter chillies.

Harvesting normally starts in mid to late summer, depending on when you have sown the seeds and if you have grown inside or outside.

You should be able to harvest into autumn. We were still harvesting our chillies in November.

Pick your chillies by twisting the green stems. You want the stems to come off too, as otherwise the chillies will go bad quicker. It’s similar to picking tomatoes.

Top Tip: If you have big harvest and you decide to chop and freeze your chillies, wear gloves to do so. 

I didn’t do it. I was chopping hot chillies for about an hour. Then I started to get a burning feeling in the hand I held the chillies with. The pain got so bad that I couldn’t sleep.

I spent most of that night in the kitchen with my hand dipped in vinegar. Wear gloves when chopping chillies, to avoid sharing my experience.

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Pests And Diseases That Could Affect Your Chillies

severe infestation of cabbage aphids

No guide about how to grow chillies from seed in the UK would be complete without a section about pests and diseases.

After all, for a successful yield, you have to be able to protect your plants from harm caused by pests and diseases.

Pests

There are a few pests that might attack your chilli plants. One of them are aphids.

These little round insects will suck the sap of the plants. You will find them on the stem and under leaves. They love new shoots, so it’s the first place to find them.

A few aphids won’t do any harm, but if a colony develops, they could stunt the growth of your plants.

There are ways to prevent aphids spoiling your crop:

  • check your plants regularly and remove the aphids if they seem to grow in number
  • encourage natural aphid predators in your garden, such as lacewing, parasitic wasps or ladybirds – I use this method and it works well
  • companion planting also works – plant chives, garlic, onions or basil with your chilli plants
  • you can also use horticultural liquid soap to wash off aphids, if a colony has established

We have used this one before and it worked well.

Pure Organic Neem Oil and Horticultural Gentle Liquid Soap Combo Pack 1 litre (or select 250ml) for Spray Plants Pets Animals Dogs Horses PINK SUN 1000ml 1ltr
  • Pure organic cold pressed neem oil concentrate unrefined one 1000ml bottle
  • Gentle biodegradable liquid soap derived from plant oils one 1000ml bottle
  • Combine together with water to form a neem spray or drench

Another pest that might nibble at your chilli plants are whitefly. These are mostly a problem if you are growing your chillies in a greenhouse or polytunnel.

Like aphids they drink the sap of plants, but they have wings. Here are some tips how to keep them away:

  • clean your greenhouse or polytunnel in winter to get rid of any whitefly colonies that overwinter there
  • encourage natural predators of whitefly in your garden, such as ladybirds and lacewings
  • companion planting also works – basil is great at deterring whiteflies and it grows well in a polytunnel or greenhouse

Red spider mites also tend to be a problem for chillies that are grown indoors. Another of these sap-sucking insects.

These tiny little red insects look a bit like spiders, but they are mites. They love hot, dry conditions.

Here are some things you can do to prevent red spider mites from becoming a problem:

  • clean your greenhouse or polytunnel over winter to get rid of overwintering populations
  • mist your chillies as the humidity will deter the spider mites
  • weed you beds in and around the greenhouse or polytunnel, this will give them less food
  • encourage beneficial insects into your garden – again ladybirds and lacewings will be a great help
  • companion planting: chives, onions, dill and garlic will deter them

Diseases

blossom end rot on a tomato

One disease that could affect chillies is blossom end rot. Well, actually it’s not a disease, but it worth knowing about it.

When chilli plants lack calcium, they can be affected by blossom end rot. You will see brown or black patches on our chillies.

The main cause for this problem is irregular watering. While it is good for chillies to dry out, you should still water them regularly.

Any fruits that are affected need to be disposed of as you can’t eat them.

Another diseases is grey mould. This is more of a problem in greenhouses and polytunnels than outside.

Like other mould grey mould likes the warm and humid conditions. 

Make sure you ventilate your greenhouse or polytunnel in hot weather. And check often for dead plant material and remove it. 

Grey mould will affect dead or dying material first and then move on to your healthy plants.

Also make sure there is good air circulation between your chilli plants, so don’t be tempted to plant too many in one bed or too close together.

Can You Grow Chillies In Posts?

This is a question I had when I first looked into growing chillies, because we didn’t have polytunnel then. So I thought I would include it in my guide about how to grow chillies from seed int the UK.

The short answer is yes, absolutely. Chillies are a great crop for containers, as they don’t need that much space. Especially the bushy varieties of chilli, such as Habanero work well in pots.

You still want to grow them in a polytunnel or greenhouse if you can though. Or on a sunny windowsill in the bathroom, where you have perfect conditions for chillies.

You follow the same steps described above, but rather than planting out, you plant your chillies in a large pot, about 30cm (112in) will do it.

Feed and water sparingly as mentioned above. But keep in mind that soil in a container will dry out quicker.

Now that you know how to grow chillies from seed in the UK, you are ready to go. Happy Growing!

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