One of our FAQs is ‘How do you grow chillies on a window sill?’. Our stock answer is, ‘With a bit of care’. As you can imagine, growing a tropical plant like chillies on a windowsill – where heat and light may be in short supply – is not an ideal scenario. It is, however, perfectly possible to raised chilli plants on a windowsill with some success. However, to get best results a few considerations must first be made.
Use a south facing window
The south side of British homes get the most sunlight, and this is where the plants should be grown. East and west facing windows might do, but the plants will struggle. If you have the time and discipline, you could move plants around the house to follow the sun and get more light on them. Another trick is to put a mirror or some reflective material (available from hydroponic shops) behind the plants to shine the light back on them. But whatever you do, forget about using north facing windows – you’re simply wasting your time putting plants there.
Choose short, compact varieties that are adapted to small pots
Smaller varieties grown in small pots will fit on a window sill without falling over.
Grow a variety with a heat level that suits your needs
If you have a chilli plant you will want to enjoy the plant while also being able to use the chillies in the kitchen. Chillies vary enormously in heat level so it is worth getting one that has a heat level that suits your needs.
Do not over water or excessively fertilise
Because of lower light levels, plants grown on a windowsill need to be watered and fertilised less often than those in a greenhouse or tunnel. Add water only when the compost begins to dry out, and give a liquid feed no more than once every two or three weeks.
Place the pots in a plate or dish
No matter how careful you are with watering, some of the water will inevitably escape through the hole in the bottom of the pot. Putting the pots in a dish or plate will catch the water and prevent it from spreading over the window sill and making a mess of things.
In the summer aphids – also known as greenflies – reproduce asexually. This means only one aphid getting into the house accidentally will reproduce and infect your plant. In addition, there are no insect predators living indoors to control the aphids. So if you have a chilli plant on a windowsill it is very likely that at some point, it will be attacked by aphids. Do not ignore them, left alone aphids will devastate a plant. To bring them under control, wash them off under a stream of water, or spray the plants with an innocuous pesticide that won’t poison you or members of your family. For more details click here.
Open the window, shake the plants or hand-pollinate the flowers
Chilli flowers will self-pollinate, so they do not need any insects to aid pollination. But some varieties, especially the habanero chilli type (C. chinense) chillies, need some movement in the branches to help the male and female flower parts touch. Thus, in the still conditions of the house, chilli flowers may not pollinate and set fruit . To aid pollination the branches need to be shaken gently on a regular basis. The easiest way is to keep the plant near an open window where the breeze will do the job. If that is not possible be sure to shake the branches whenever you go near the plant.
Low light levels might also cause the flowers to drop before being pollinated, in which case there is nothing you can do except expose the plants to more light.