Growing chilli peppers in containers and gardens (selfsufficientish)

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Chili Peppers – Capsicum by the Chili Monster part 1

The chili plant originated in Latin America, where it was cultivated from its wild form by South American Indians. Christopher Columbus is regarded as the first European to sample the fruit, and indeed coined the term pepper. With the Spanish firmly in control of the Mexican economy, the chili was introduced initially to the Philipines and then to China and other parts of Asia. (It should be noted that some believe that it was the Portuguese that introduced the chili to Goa where it became a constituent of curry). Although grown as an annual outside of its native South America, the chili is in fact a perennial shrub that can tolerate temperatures ranging from 7 to 29 degrees centrigrade, annual rainfalls between 0.3 and 4.6 m and soil pH 4.3 to 8.7. From the container-suited Dwarf Apache and Thai Sun varieties through to the large but very mild Anaheim, from the pungent (hot) Mexican Tepin to the ornamental Purple Prince, there’s a chili pepper cultivate suited to every gardener.


Although it is advantageous to grow peppers in a greenhouse or conservatory, chili plants will thrive outside in areas of the UK south of North Wales once night time temperatures reach 10 degrees centigrade and above. Like tomato plants, pepper plants rarely withstand even the slightest frost. It should be noted that the growth of pepper plants is slow at temperatures below 15 degrees centigrade, the flowers form at temperatures of 18.5 degrees centigrade and fruit formation is hampered by temperatures over 32 degrees centigrade. Chili plants prefer a well-drained, sandy or silt-loam soil. If growing outside then stand the plants 18 cm apart in a sunny but sheltered site.


Sow seed in a seed tray charged with moist multipurpose or organic peat-free compost mixed with sand or vermiculite to aid drainage at a depth of 2 cm, cover lightly with compost and either place in a heated propagator set to 20-30 degrees centigrade or cover with clingfilm and perforate (to allow ventilation) then place in airing cupboard. At no time allow the compost to dry out; check at frequent intervals and water (boiled and left to stand for 24 hours so that any chlorine dissapates) with a spray (as appropriate). Germination typically occurs between 20-30 degrees centigrade but it is important to maintain a constant temperature (wild fluctuations will result in weak plants) and time required for germination to take place depends very much on the type of pepper. Habaneros can take up to a month. You may follow the directions on the back of the seed packet (usually March), but as a general rule of thumb, the longer it takes for the fruit to reach maturity (90 to 120 days following transplantation for habaneros, around 90 days for Jalepenos) the earlier you should start -March is simply too late for chinenses and many chili growers in the UK begin in late December or January.


Once the seedlings have emerged remove the propagator lid or clingfilm and set the tray in a bright window sill. Water as required and treat your plants to an Epsom Salts spray once a week to encourage chlorophyll production. Grow the seedlings on until the second true leaves are developed and then pot on into 7 cm pots. Cover with moist compost to just below the first set of true leaves as this encourages the development of extra roots. Place the tip of a matchstick in the pot to provide sulphur. Remember to mix sand or vermiculite in with your potting compost. It’s acceptable to allow the top of the compost to go dry at this point as long as the the compost around the the roots is still moist (check with finger!).

Seedlings that are placed in a very warm but poorly-lit room will often grow into spindly plants with pale leaves. To avoid this, lower the room temperature to about 15 degrees centigrade. At this temperature your plants will be growing but at a reduced pace. A light box constructed from a cardboard box and tin foil (or a mirror!) will intensify the daylight available to the plants.

Apply epsom salts at least once a week or alternate with a NPK plant food in the ratio 15-15-15. Seaweed extract is a good organic choice!
Pot on: 12 cm and then 15 cm.

Transplanting out

Once the threat of a last frost has passed, and the night time temperatures have stabilised at 10 degrees cenigrade (usually mid to late May in the South East of Britain), it’s safe to move your plant outside. Just prior to this, harden off your pepper plants for a couple of weeks beforehand by opening windows, standing pots outside for short periods during the day; gradually increasing the plant’s exposure until ready to transplant.

At this point either pot the plant into 20 cm pots, transplant them into growbags (no more than 3 to a bag) or stand the plant into well-prepared soil, leaving at least 18 cm between each plant. If possible, select a south-facing, sheltered postion (the stem of the young chili plant is quite delicate and is easily damaged by strong winds). Note that compost dries out quickly in containers; likewise grow bags (think hosepipe ban!) and that plants grown in pots or bags require regular feeding (as above). When growing chilies: think tomatoes!!!

Preparing the Soil

• Refrain from growing in areas infected by nematodes or have a recent history of plant disease
• Clear site completely of weeds; pepper plants are greedy feeders, also helps prevent the spread of disease.
• Work the soil to a fine tilth and work in either rotted manure, good quality compost or fresh seaweed
• Apply mulch

Growing On

Plants grown directly in soil will require 2-3 additional side-dressings of fertiliser (well-rotted animal manure goes down well; likewise fresh seaweed, especially bladderwrack). Exercise pest control (see below). Good weed control is essential and mulching (seaweed, compost from bin, newspaper) is useful. Apply Epsom Salts as a foliar spary at fortnightly intervals; once every ten days once flowers form.

Container or grow-bag plants require a weekly feed with either seaweed extract or NPK fertiliser (15-15-15) and water as required. Control pests and treat with Epsom Salts as per soil grown plants.

Cover plants with fleece to protect from excessive heat (about 30 degrees centigrade) and later in the season as the nights draw in.

Pinching out the plants at required height will cause the plant to bush out.


Chili pepper plants develop flowers at about 18 degrees centigrade. Unlike their tomato plant cousins, chili plants require insect pollination. If you are growing pepper plants under glass or indoors, you will need to pollinate the plant yourself. However, this is easily done. When the pollen ripens each day between 12 midday and 3 pm, simply collect some on a moistened water-colour paintbrush and transfer it to the other flower centres.


Pods are unlikely to develop if temperatures exceed 32 degrees centigrade. If fruit is picked whilst young, more flowers will grow. Mature fruits will remove easily from the plant. Given the short growing season in the UK, it’s not unusual for the fruit never reach full maturity. This is especially true of plants grown out-of-doors. Three very good, legitimate, chemical-free methods that bring about ripening are:
• Pruning. Further growth will be directed to ripening the pods
• Hanging the plant upside down in a dark, cool place such as a garden shed
• Place unripened pods in a drawer with old (black) bananas


Provides the gardener with a head-start for the following season. Ideal for smaller species of chili, such as the Dwarf Apache, Thai Sun and Marble varieties. Just ahead of the first expected frost, bring the plant indoors and stand in a sunny windowsill. Keep the plant out of the draft and prevent the room temperature from falling below 10 degrees centigrade. At this temperature the chili plant may become dormant, i.e. leaves drop off; no visible signs of growth. Should this happen, the plant will require light watering a couple of times a month and one monthly feed.

Pests & Diseases

Basically, this is just good old-fashioned common sense.


Mostly Bacterial, Fungal or Viral in nature.

Bacterial Leaf Spot is a common affliction of chili plants. Characterised by small, yellow-green spots on leaves that turn brown over time. Growing both in size and number, the spots often merge into one. Wart-like raised dark brown spots may appear on fruit. Usually seedborne. Spread by splashing rain or overhead irrigation. Prevention: high-quality seed; crop rotation.

Damping Off. Fungal. Emerging seedlings wilt and die. In established plants, the root system is greatly damaged leading to stunted growth and a poor yield of crops. Prevention: high-quality seed; good drainage.

Another fungal affliction, Leaf Spot causes circular, grey spots to appear on the leaves. A severe infection results in yellowing and defoliation. Usually seedborne but can survive on crop residue.

Phytophthora Blight, a fungal infection, turns the stem (closest to the soil line) brown; wilting occurs. Soilborne. Splashing water can dislodge spores and so spread the disease. May affect the fruit. Prevention: Plant in raised beds; proper irrigation management can reduce this affliction.

As a result of another fungal foe, Powdery mildew, yellow areas appear on the upper leaf surface which may later turn brown, whilst white, powdery growth forms on the underside of the leaf. Severe infection leads to defoliation. Caused by warm, humid conditions.

Southern Blight is caused by a fungus that attacks them stem close to the soil line, causing the plant to eventually wilt and die. Characterised by the presence of a white, cotton-like growth on the surface of the stem accompanied by tan or brown spherical bodies roughly the size of a mustard seed. Prevention: Crop rotation; deep ploughing of crop residue can help.

Viruses can be seedborne, spread by vegetative propagation (grafting & budding), seed transmission or mechanically ( by insects and animals). Viral infection is difficult to diagnose since genetic mutation may mimic viral symtoms; likewise, high temperatures at planting time can result in distorted foliage.They may affect other types of plant without displaying the same symptoms. Common examples of viruses that attack pepper plants include:

The Pepper Mottle Virus is spread by aphids and causes leaf mosaic plus stunted growth. Also caused by aphids is the Cucumber Mosaic Virus which results in vascular and fruit discolouration or death of terminal portions and the Tobacco Etch Virus that can lead to mosaic, fruit distortion and stunted growth; in the Tabasco it causes a lethal wilt.Meanwhile, the whitefly carries the Texas Pepper Geminivirus, which is characterised by a yellow, mottled appearance, leaf-curling and distortion.

Other diseases include Black Spot, (cause unknown) an infection characterised by the presence of round, unraised black spots under the skin of the fruit; discolouration inside. Sunscold results from direct exposure to sunlight and is often a consequence of defoliation caused by leaf-infecting pathogens. In sunscold, parts of the fruit take on a dried, sunken and bleached appearance. As a fungus takes hold, the disease often takes on a black, velvet appearance.


Cats and dogs may trample over plants, dig up beds, urinate over plants, pull off flowers.

In the United kingdom the most common pests in this part of the world are ants, aphids, cutworms, spider mites, slugs and snails

Tips and Hints

This list is by no means exhaustive:

• Clean tools after each use
• Good hygiene is essential
• Implement crop rotation
• Use raised beds
• Practice good watering technique
• Applied directly, biodegradeable detergent kill aphids
• Regular weeding helps prevent disease in the long run; ants apparently don’t like this either
• Prepare soil thoroughly
• Disinfect containers, seed trays, propagators thoroughly. Dettol is good but tea-tree oil and camomile tea make good alternatives and are safe to use on plants
• If you have a problem with cutworms, then a paper cup with the bottom cut out, placed around the stem roughly 1/2 inch into the ground should protect the stem
• Companion planting∞: basil∞, dill∞, chives∞ and chervil all repel aphids. No aphids, fewer ants! For tips on how to deal with ants, visit: Getting rid of ants∞
• Grow marigolds and other yellow flowers along side your chili plants to attract natural aphid predators, such as wasps and ladybirds, and hoverbugs to pollinate plants. The flowers can be used later to make wine∞!
• Sow only good quality, disease-free seeds
• Never overcrowd plants
• Ventilate propagators and seed trays: remove lids or clingfilm for at least ten minutes each day
• Grow coriander∞: not only does it ward off aphids, it can also be turned into a spray to kill spidermites
• If cats are a problem, plant some curry plants – cats don’t like the smell
• Read 101 ways to get rid of slugs∞for advice on battling those gastropods
• Remove infected plants immediately but refrain from adding them to your compost heap
• Avoid growing peppers on land recently used to grow potatoes∞, tomatoes∞ or aubergine (egg plant)

Collecting the Seeds

Select only fresh, healthy, ripe and fully-coloured chili peppers for this purpose. Resist using seeds that are more than a year old. However, if you choose to grow from old seed, be sure to sow an excess to allow a maximum crop. Harvest the seeds manually first by gently breaking open or cutting open the pod as to leave the core intact and then leaving the stem attached as a handle, scrape the seeds out into a bowl with a small knife. Alternatively, cut off the stems then place the cores (minus the flesh) in a food processor/blender with just enough water to cover them and blend until the seeds are free. Since the good seeds sink to the bottom, gently pour off some of the water together with the bits of core and imperfect seed, introduce some more water and blend further. repeat this process until the only seed remaining is at the bottom. Sieve the contents of the blender, dry the bottom of the strainer on a towel and turn the seeds onto a dish to dry.

Always dry chili seeds away from direct sunlight. The seeds are ready for storage when the seeds break on folding. Keep the seeds in an airtight container (preferably glass or metal) such as a baby food jar. To keep moisture at bay, simply add a bit of rice.

Suggested Further Reading

see the orginal article on our wiki site for links


Janis McPhilomy’s Article, The Men behind the Chile Pepper
Michelle Stelter’s Article, Hot Peppers: They’re not just for Eating.


Growing Peppers in the Home Garden∞
Watch Your Garden Grow: Peppers∞
Growing Peppers is fun, Easy and Addicting∞
How to Make a Compost∞
Companion Planting∞

Matthew Bellringer’s Article: Capaicinoids – What makes Chilies hot?∞

Published by

Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.

8 thoughts on “Growing chilli peppers in containers and gardens (selfsufficientish)”

  1. Pingback: Aeroponic System
  2. I am attempting my first indoor garden, this has been very helpful, though I am sure I will still make my share of mistakes. Thanks again for the great advice.

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