If you want to plant basil, you need to find the right spot. Read on to learn how to grow basil from seed, and cultivate an abundant and delicious harvest.
The popular, aromatic herb basil (Ocimum basilicum) most likely originated in India or Afghanistan. However, it is most famous in Italian cuisine; Italians began using the herb in the 12th century. There are many varieties of basil, each containing different essential oils. It is these essential oils that create such diverse basil flavours, ranging from lemon to cloves and even aniseed.
Nowadays, you can buy basil as a potted herb in almost every supermarket. But it has been a favourite of hobby gardeners for much longer. Here, we show you how to grow basil in your garden or on your windowsill – it’s a lot simpler than you might think!
Growing basil from seed
Growing basil at home is not difficult. It just requires a little patience and a warm, bright location. Because basil develops so slowly, it is rarely sown outdoors in our part of the world. Here are our tips for sowing basil indoors.
Given enough warmth and light, you can sow basil seeds indoors year-round. To do this, fill your sowing container with moistened, low-nutrient soil. Then scatter your basil seeds over the surface of the soil and press down lightly so that the seeds are in contact with the soil. Basil, like many herbs, is a light germinator. This means that the seeds germinate best when they are exposed to light and not buried in the soil. Be sure to sow the seeds 5 cm apart from one another, and moisten everything using a spray bottle.
At 18 to 22°C, basil takes about two weeks to germinate. After germination, however, it is best to move your basil to a slightly cooler place, as it will grow better at around 16°C (at least, to start!). After about four weeks, the basil can be pricked out. This is done by carefully lifting out and separating individual plants with a pricking rod or a wooden stick. After pricking out the basil, place each plant 25 to 30cm apart from one another in a nutrient-rich soil. This should encourage healthy development.
- Sow seeds 5 cm apart
- Basil is a light germinator
- Optimum germination temperature: 18-22°C
- After germination, grow at around 16°C
- After another four weeks prick out and plant 25-30 cm apart
Where to grow basil
Basil prefers a warm, semi-shaded location in nutrient-rich, loose and well-drained soil. The optimal pH value for this Mediterranean herb is between 6.5 and 7. A greenhouse is an ideal place to grow basil. Here, it will grow very large, and provide enough leaves for a pesto!
Tip: Basil makes a great companion plant for tomatoes (Solanum lycopersicum). The aromatic herb keeps pests like whitefly away from the tomatoes and at the same time benefits from the shade provided by the tall, nightshade plants.
Temperatures below 8°C are usually life-threatening for basil, but some varieties can tolerate temperatures as low as -10°C. To be on the safe side, however, always keep your plants indoors or in a conservatory over the winter. Growing your basil in a pot makes it much easier to put it outside during summer, and bring it back in during winter. Read our article on overwintering basil to find out more. Although it can be tricky, overwintering basil is definitely worthwhile!
You can grow basil from seed, propagate it from cuttings, or use ready-grown plants. Basil grows outdoors or in a pot, and, with the right location, even supermarket varieties can grow into vigorous and productive shrubs that reach up to half a metre in height. Ready-grown herbs always contain several plants, so when transplanting the basil, try to divide them so that each plant has enough space.
Planting basil indoors
It is possible to grow basil indoors from seed at any time of year. However, you can also cultivate pre-grown plants. Using a pot on a warm windowsill is a good option here. Choose a pot with a volume of about 3 to 5 litres, so that your basil has enough soil and nutrients to grow large and healthy.
There is often some confusion about what kind of soil is best for basil. Pre-grown basil requires a medium amount of nutrients. As such, avoid typical herb soil, which is low in nutrients, and instead fill your container with a more nutrient-rich, vegetable soil.
Tip: Basil needs a lot of warmth and can struggle outdoors in cool summers. Sowing basil in winter on the windowsill rarely results in high-yielding plants. Even supermarket basil will struggle to grow large in a conservatory. This makes it all the more important to harvest plenty of basil during the summer, to build up stocks for the winter!
Planting basil outside
Do not plant your basil outdoors until the end of May, once there is no chance of frost. Choose a warm, bright location, but avoid full sun. A half-shaded corner of the balcony; a raised bed; or under tomatoes in a greenhouse are all good homes for basil. For supermarket basil, give each plant 25 centimetres of room to grow. While individual, vigorous basil plants need about 10 to 15 centimetres of room.
Tip: Compared to other herbs, basil likes nutrient-rich soil. However, too much fertiliser can damage the plant. Over-fertilisation leads to fungal disease and pests. As such, avoid fertiliser if you have nutrient-rich soil. With good garden soil, meanwhile, reach for a slow-acting natural fertiliser, like Plantura Tomato Food.
Once you have transplanted your basil, there are still a few more things to do. Read our article on basil care to learn all you need to know about watering, fertilising and pruning basil.