What is a jalapeño?
A jalapeño is a type of chilli pepper that originates from Mexico. It is a medium-heat chilli known for its great flavour and relatively mild spiciness. The fruits grow to around 5–8 cm long and are most often harvested green, but they can also turn red if left to fully ripen. Jalapeño belongs to the same species as sweet pepper (Capsicum annuum) and is grown as an annual plant in Sweden (in warmer countries it is perennial). Growing your own jalapeño in a pot is both fun and educational – perfect for beginners who want to try growing chilli! A potted jalapeño plant usually reaches about half a metre in height and can produce plenty of fruits in late summer if it is happy.
How to plant
To succeed with jalapeños in Swedish conditions, you need to start growing indoors well in advance. Sow the seeds indoors during winter/early spring (ideally in February or March) so the plants have time to develop before summer. Use small pots or seed trays filled with seed compost. Jalapeño seeds are light germinators, meaning you should only cover them very lightly with compost, or simply press them onto the moist surface. Mist or water the sowing gently so the compost stays evenly moist. Then cover the pot with cling film with a few air holes, or use a mini propagator with a lid, to retain humidity and warmth. The seeds germinate best in warm conditions – around 20 to 25 °C. Place the sowing somewhere warm; above a radiator or on top of a fridge can provide extra bottom heat that speeds up germination. Be patient: it can take 1–2 weeks (sometimes longer) before the first shoots appear.
Once the seeds have germinated and the small seedlings begin to emerge, they need plenty of light to grow stocky and strong. Place them in a bright spot, such as a sunny window. In early spring, however, daylight is often not strong or long enough for chilli plants to develop well, so use a grow light for about 14–16 hours per day if possible. Keep the temperature at around normal room temperature (approximately 18–20 °C) after emergence – too much heat combined with weak light can cause leggy growth.
When the seedlings have developed 2–4 true leaves, it is time to pot them on into individual larger pots with nutrient-rich potting compost. Handle the roots carefully. You can plant the jalapeño seedling a little deeper than before (up to the lowest leaves), which encourages extra roots to form along the stem and makes the plant sturdier. Continue potting on gradually as the plant grows. Ultimately, each jalapeño plant needs a pot holding at least around 5 litres of compost – preferably larger (8–10 litre pots usually give bigger yields). A spacious pot with drainage holes gives the roots room and reduces the risk of the compost drying out too quickly on hot days.
Care and placement
Sun and warmth: Jalapeños love warmth and light. Place your plant as sunny as possible – a bright indoor windowsill, a glazed conservatory or a greenhouse is ideal. During summer, jalapeños also do well outdoors on a balcony or sheltered patio, as long as they get lots of sun and comfortable temperatures. Wait to move the plant outside until the risk of frost has passed and night temperatures stay above about 10 °C. When moving it outdoors, harden it off first: let it get used to outdoor conditions by placing it outside for a few hours each day for about a week, gradually increasing the time. This prevents shock from strong sun or cool winds. Jalapeños thrive best in sheltered spots – for example next to a house wall that stores heat. If you grow several jalapeño plants, they can be placed close together, but give each plant its own pot so they do not compete for space.
Watering: A jalapeño needs a steady supply of water. Keep the compost slightly moist at all times, but avoid waterlogging. Check with your finger; if the top centimetre feels dry, it is time to water. During hot midsummer days, daily checks may be needed so the plant does not dry out, especially in smaller pots. At the same time, excess water must be able to drain away – roots do not like sitting in wet compost. Always use pots with drainage holes and ideally a saucer underneath to catch runoff. Empty the saucer if a lot of water remains some time after watering.
Feeding: To produce lots of fruits, your jalapeño needs nutrients. Start feeding once the plant is established in its final pot or when you see the first flower buds. You can mix a slow-release fertiliser into the compost when potting on, or apply a liquid feed about once a week during the growing season. Tomato feed or a general vegetable fertiliser works very well, since jalapeños have similar nutrient needs to tomatoes. Avoid overfeeding – follow the dosage instructions. Too much nitrogen can result in lots of leaves but fewer flowers, so balance is important.
Flowering and pollination: Jalapeños produce small white or pale yellow flowers before the fruits develop. These flowers are self-fertile, but pollen still needs to be moved between the anthers and stigma for fruit to set. Outdoors, insects and wind usually handle pollination, but indoors or in a greenhouse you may need to help. Often it is enough to gently shake the plant now and then while it is flowering – a light breeze or small nudge moves the pollen. You can also carefully touch inside each flower with a soft brush or cotton bud to transfer pollen if you want to be sure. If flowers drop without setting fruit, it may indicate pollination issues or unsuitable growing conditions (see tips below).
Pruning and support: Jalapeños usually form a bushy, stable plant that does not need pruning. However, it can be helpful to pinch out the tip when the plant is small – for example when it reaches 15–20 cm – to encourage branching and a sturdier shape. If a very small plant produces flower buds early, you can remove the first buds so the plant puts energy into growth before fruiting, which often leads to more chillies later. Jalapeños generally do not need staking, but if your plant grows tall or carries many heavy fruits at the same time, it may benefit from support. A bamboo cane or plant support placed in the pot can hold branches up if they begin to droop. Insert the cane carefully to avoid damaging roots.
Pests: Sometimes pests find chilli plants, especially if they stay indoors for a long time. Aphids and whiteflies are the most common problems. Check the undersides of leaves for small green aphids or tiny white flying insects. If you spot pests, isolate the plant from other houseplants and treat it. A tried-and-tested method is to spray the leaves (especially the undersides) with a solution of soft soap and water. Mix about 1–2 tablespoons of soft soap per litre of lukewarm water and spray thoroughly, repeating a few times every few days until the pests are gone. Spider mites can also affect chilli plants in dry indoor air – look for fine web-like threads. Increase humidity and mist the plant regularly to help prevent them. Fortunately, a healthy jalapeño plant can often tolerate some pest pressure and still produce a harvest, but it is best to deal with problems early.
Tips and frequently asked questions
Can you grow jalapeños outdoors in Sweden? – Jalapeños do best in pots, either indoors or in a greenhouse, but it is fine to place the pot outside during summer. Planting directly in the ground is more difficult because chillies want warm roots and consistent protection from cold. In southern Sweden you can try growing jalapeños outdoors in a warm, sheltered spot, but pot growing usually gives better results because you can move the plant indoors if the weather turns cold.
Do I need grow lights to grow jalapeños? – It depends on when you sow and how bright your conditions are. If you sow early in the year (mid-winter or early spring), supplemental light is almost essential to prevent leggy plants – daylight is simply too weak and short. A good LED grow light makes a big difference. If you sow later, for example in April, and have a very sunny window, it may work without extra light. In general: the more light the plants receive, the better they grow and the more fruit they can produce.
Why are no fruits forming on my jalapeño? – If the plant flowers but no small chillies develop, it may be due to pollination issues or stress. Cool temperatures (below about 15 °C) or very high heat above 30 °C can cause flowers to become sterile or drop. Uneven watering (drying out followed by heavy watering) can also stress the plant. Keep it warm and sheltered, water regularly, and help pollination by gently shaking the plant while it flowers. Another reason can be too much nitrogen fertiliser, which makes the plant focus on leaves instead of flowers – try reducing feeding temporarily.
Can I overwinter my jalapeño plant? – Yes, you can overwinter a jalapeño if you want to keep it for next season. Chilli peppers are perennial by nature, so if the plant is protected from frost it can live for several years. Before autumn gets too cold, bring the plant indoors. Prune it back fairly hard (you can remove a third of the branches or more, and remove any remaining fruits). Place it somewhere bright and cool, such as a window in a room that is not too warm. Water very sparingly over winter, just enough to prevent the compost drying out completely. Some leaf drop is normal as light levels decrease. With supplemental grow lighting and good care, the plant can survive winter and start growing again in spring. Remember to repot into fresh compost and a larger pot when spring arrives for a fresh start.
How hot are jalapeños compared to other chillies? – Jalapeños are considered mild to medium hot. On the Scoville scale, jalapeños are typically around 2,500 to 8,000 Scoville Heat Units. This is much milder than habanero or bird’s eye chilli, but still hot enough to add a kick. If you are sensitive to heat, you can reduce spiciness by removing the seeds and the white membranes inside the fruit, where much of the heat is concentrated.
Can I save seeds from a shop-bought jalapeño and grow them? – You can collect seeds from a ripe jalapeño and sow them, but there are a few things to keep in mind. The fruit should be red and fully ripe for the seeds to be developed enough to germinate. Seeds from green, unripe jalapeños rarely germinate. Dry the seeds and store them in a dark, dry place for a couple of weeks before sowing. Also remember that if the jalapeño you bought is a hybrid variety, the offspring may have slightly different characteristics. For beginners, buying seeds from a seed company is easiest – but experimenting can be fun.
Do you need gloves when handling jalapeños? – Jalapeños are milder than many other chillies, but they still contain capsaicin, which can irritate skin and eyes. Gloves are not strictly necessary for most people when harvesting or slicing jalapeños, but they can be a good idea if you are sensitive. Above all, avoid getting chilli on your eyes or other sensitive areas – wash your hands thoroughly after handling fruits or the plant. A common mistake is rubbing your eyes or lips after cutting chilli, which can sting a lot. So be careful and practise good hygiene when handling chillies.
When can you harvest?
Jalapeños take time to develop fruit, but once the plant gets going it can produce over a long period. If you sow seeds in February/March and care for the plants well, the first flowers usually appear in early summer. From flower to harvest-ready chilli can take a few weeks up to a couple of months depending on temperature and variety. Many growers find the first jalapeños can be picked in July or August. In a greenhouse, the harvest may start a little earlier, and outdoors on a balcony or in open conditions a little later.
You can harvest jalapeños when the fruits are green and full-sized, usually around 5–8 cm long and firm. A green jalapeño has a fresh, medium-heat flavour and a slightly crisp texture – perfect for eating fresh or pickling. If you leave the fruit on the plant longer, it will eventually change colour to deep red. Red jalapeños are fully ripe and often slightly sweeter, with a fuller aroma. The heat can feel a little stronger in fully ripe fruit, but above all the flavour depth changes. This means you can choose whether to harvest your jalapeños green or red depending on taste and use. Many people pick the first fruits green to encourage continued fruiting, and let the last fruits of the season ripen fully to red.
When harvesting, use sharp scissors or secateurs and cut the fruit just above the stem to avoid tearing and damaging the plant. You can also gently snap the fruit off by bending it upwards until it releases. Harvest regularly as the fruits ripen; picking chillies often encourages the plant to produce new flowers (as long as the weather and season allow).
In Sweden, the outdoor season ends when autumn cold arrives. Jalapeños cannot tolerate frost, so bring the plant indoors or pick all fruits before the first night frosts in late autumn. If you have many green fruits left at the end of the season, you can hang whole branches indoors or place the fruits in a sunny window – some may continue ripening to red even after picking, especially if they have already started changing colour. Otherwise, green jalapeños are excellent to use as they are. For example, you can pickle them in a vinegar brine with sugar and spices to make your own pickled jalapeños, which is a great way to preserve a large harvest. Surplus jalapeños can also be frozen whole or chopped (they become a bit soft when thawed, but are great for cooking). And if you have lots of red jalapeños, you can try drying or smoking them – dried red jalapeños are what is known as chipotle, a smoky spice popular in cooking.
Harvesting your own homegrown chilli is a wonderful feeling. Enjoy the results in the kitchen – finely chop fresh jalapeño into salsa, bake cheese-stuffed jalapeños as snacks, or top your pizza and tacos with homegrown chilli. Good luck growing jalapeños!