Hot chillies!


Helen Simpson, from the Mushroom Shed, tells you all you need to know about growing chillies. She has also written articles about growing basil, brassicas, coriander, cucurbits, garlic, ginger & turmeric, mint, rhubarb, strawberries, tomatoes and lesser known herbs.

Additional material from Guy’s tips: capsicums, chillies and eggplants.

Capsicums, chillies and eggplants are perennial but short-lived, typically living for around three years. But, and here's the main point of this little article, they are frost tender and are typically killed off by the Melbourne Winter. So, if you want to get full value from your capsicum, chilli and eggplant plants, you need to grow them in pots and put those pots in a warm place (e.g. a greenhouse) during Winter. If you have some and they are outside, now is the time to move them to a warmer place (it would have been even better if you had done this before the latest cold spell!).

chilliAnyone who has tasted or handled a hot chilli will be familiar with their stimulant effects – increased perspiration, burning sensation in the mouth, running nose and eyes and laxative effect – dare I go any further.

These sensations vary with the type of chilli and are due to the amount of the chemical compound ‘capsaicin’ contained in the chilli. This compound varies from negligible in the standard capsicum to a significant amount in the very hottest chillies.

Chillies and capsicums all belong to the Capsicum genus, which contains several different species and are native to Central and South America. Numerous varieties exist – some pointy and small, others round, oval and fleshy and some look like miniature hats (e.g. the Emperors Hat or Scotch Bonnet). Colours include green, yellow, red, purple, orange, chocolate and black.

How hot is a chilli?

Chillies are generally measured in heat units using the Scoville Scale, which was developed in 1912 by Wilbur Scoville. The heat units are related to the amount of capsaicin in the chilli.

For example (and depending on your reference source), the Cayenne and Rocoto Chillies have Scoville heat units of around 35,000, the Habanero around 300,000, the Trinidad Scorpion and Naga (ghost) chilli 800,000 to 1,000,000 or higher. Wikipedia puts the Carolina Reaper chilli at around 1,600,000 to 2,200,000 heat units.

Milder chillies include the Jalapeno (2,500 to 8,000). The humble capsicum is neutral.

Some of you may have heard of the Padron chilli, of which 1 in 10 are reported to be extremely hot and the rest not so. However I’ve heard varying reports on the authenticity of the 1 in 10 probability – some experimenters reporting that they are all very hot.

Growing chillies

Chillies can be started from seed. However, as the seed can burn, care should be taken and thin plastic gloves worn. Start the seeds indoors in a small punnet or pot in October/November and transplant outdoors only when weather is consistently warm – usually early December.

Chillies generally only thrive in hot, sunny weather, so in Melbourne they have a limited growing season and are usually grown as annuals. For this reason, you may prefer to begin with a small chilli plant rather than seed, to get a head start.

With care and management, chillies grown in pots can have their season extended by bringing the pot up on a sunny veranda or placing in a greenhouse when the weather starts to cool.

The Rocoto (or Manzana) chilli is one exception. Whilst severe or successive frosts can damage the plant, it usually recovers sufficiently to grow even bigger the next year. Eventually it will be the size of a large bush and you may have to cut it back with a pair of large clippers to deter its sprawling habit. It will most likely produce more chillies than you can use. Take care – the chillies from the Rocoto can be very hot.


Around late summer, fruit starts to form. Depending on the type of chilli, it is usually green, before ripening to its final colour which may be red, purple, black, orange, yellow etc. It can be picked and used green, however will be hotter if you wait until it ripens. Fruit may be on the bush right into winter.

Some varieties lend themselves to drying e.g. Cayenne or Birdseye chillies. They can be strung up in bunches. The larger, fleshy chillies are not as successfully dried like this, so are best used fairly quickly.

Common varieties

For those people seeking out the hottest chilli available, try the Naga (or ghost) chilli, Trinidad Scorpion, or Carolina Reaper (if you can find it here). But beware – they are extremely hot. Other hot chillies going down the scale of heat are the Scotch Bonnet, Habanero or Tepin, and then Thai, Birdseye, Rocoto and Cayenne.

For those seeking a milder chilli, try the Jalapeno or Emperors Hat – the Emperors Hat is also a chilli that can survive a Melbourne winter if you are lucky.

Chilli heat management

If you have eaten a chilli that is too hot, milk or yoghurt helps to relieve the burning sensation. It is reported that water tends to just spread the heat, rather than relieve it. Care should be taken handling chillies as the heat from the juice will spread onto anything you touch.

And finally …

Being a strong irritant, capsicum spray is used by the Australian Police Force.

  15 Responses to “Hot chillies!”

  1. Do you need a licence in certain states to grow certain plants?

  2. Hi Helen,

    I’m back recently from Peru where we did a cooking class in Lima. Aji Amarillo is the staple of Peruvian cuisine but almost impossible to find in Melbourne (other than preserved or paste) so I’ve had some seeds mailed to me. Now I’m extremely stressed about not stuffing up in my foray into growing chillies. There’s a little label on the packet that says “Sow Sp-Su, 5mm deep in equal mix of river sand, med coarse perlite, peat moss/coco coir & fine compost/worm casting. SOIL TEMP 18-20C MUST. Emerge 10-30d. Harvest after 90d.” It’s the beginning of November now so I need to get my skates on. The specificity of the instructions has caused my levels of anxiety to rise even more however haha. The guy at the local nursery who professes to be a soil expert said that I’d be fine with just standard seed raising mix. I’ve no idea how I go about measuring soil temperature. Can you give me any further tips here to make my dreams of growing aji amarillo true?

    • I should probably be a bit more specific. As seedlings how far apart should I place seeds (2-3 per hole yes) and how often and how much should I water them?

    • Hi Jason,

      I agree with your local nursery guy – standard seed raising mix should be fine. Yes, the soil does need to be warm to raise chilli seeds – you can measure via a thermometer if you get really keen, but generally just find the warmest spot you can. To create a warm environment, raise seedlings inside the house in a small punnet or pot (not direct sunlight, as it will fry the seedlings when they start to emerge) – if you have a bottom heating mat all the better, but not necessary.

      Keep seed raising mix moist, but not soggy. Once seedlings emerge, start giving them sun during the day and grow to around 6cm in the punnet, then transfer to their final ‘home’ – outside (larger pot is best, but you can also do directly in the garden – sunny position) – protect from snails, slugs, possums etc.

      As seedlings, a few cm apart is fine but, when larger, one per pot, or about 30 cm apart if planted in a row. Watering depends on the type of day – probably every day on really hot days, maybe every 2nd day if not so hot. The aim is to not let them dry out, or have them with soggy roots.

      Regards, Helen

  3. Chilies freeze well and can be added to casseroles and curries throughout the year.

  4. Hi Helen thanks for this post!

    Last season I planted before summer came around and ended up five plants with healthy green leaves but they did not produce any fruit. Do you have any suggestions as to why this happened? I did add seasol but it did not help.

    • Hi Stefan,

      Chilli plants can be slow to grow and sometimes the fruit doesn’t appear until well into autumn. One suggestion is to try planting a few weeks earlier this year, keeping the plants indoors if nights are still cold until warmer weather arrives. Otherwise, see if you can keep your plants through winter (this will involve protecting them in a warm spot) so the plant is well established when summer comes again.

  5. Hi – I moved into a house with two large chilli plants in the garden. It’s a cold winter but both of the plants (one is a birdseye and the other looks like a long chilli – red and green) are still producing plenty of chillis. They are both looking really sad though. They are planted in a garden bed so I can’t bring them in. What should I do to help them?

    • Hi Sandy, assuming they are too big to dig carefully around and uproot and place in a pot, leaving them as is will be the best option. If they have survived the winter so far, they will probably continue to do so – they will look sad until Spring when they will start to sprout again. You could try wrapping some protection around them on frosty nights (take off in the morning). If you like the chillies, I’d get the seeds out of the chillies and plant the seeds in a pot in November. That way, you can grow some in a pot, in case you ever lose the ones in the garden. Regards, Helen.

  6. Hello, I planted an Indian chilli plant in my backyard (Melbourne). This chilli has medium heat, but some animal/ bird eaten all the chillies, including leaves and soft branches, in the night. Any suggestions how I could to protect my chilli plant from animals/birds? Thanks.

    • Hi Vibs, it is probably a possum that has eaten it. The only reliable way of protecting plants at night is by netting, unfortunately.

      Regards, Helen

  7. I want to grow chilli’s that are not too hot for making sweet chilli sauce. What type do you recommend?

    • Hi Juliet,

      I’d recommend the Jalapeno, and also scale down the amount of chilli you put in the sauce if you want it milder. Regards, Helen

  8. Hi,
    More of a question than a comment if i may. Can chillies be grown throughout the year in a greenhouse environment? I have managed to grow garlic in pots this way in August and i am hoping for success when i plant them out in April….as i said, “hoping”
    Best Regards,

    • Hi Elliot,

      You may be able to keep chilli plants alive in a greenhouse over winter in Melbourne, however it’s likely they will lose their leaves and won’t produce chillies. If the plants survive the winter, they will start growing and producing leaves again in Spring – so you will get a ‘head start’ on chilli plants started from seed in Spring.

      If you want a chilli plant that will go through winter without a greenhouse, try the Rocoto chilli. It will generally get beaten back by the frost, but will revive again in Spring. Beware – it turns into a very large bush!


      (Note: garlic is a winter plant, that does best out in the cold. The cold weather forms the bulbs. Plant early April, and harvest early December.)

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