Very tender annual
Height 30 to 60 cm; spread 30 to 45 cm.
Highly aromatic branching herb that forms large, lush mounds in the garden or container.
Ocimum basilicum ‘Sweet Basil’ is the standard, familiar green basil; it’s prolific, with nice fragrance and colour.
Ocimum basilicum ‘Dark Opal’: Nice spicy flavour, strong flavour and scent; leaves deep purple and bronze
Ocimum basilicum ‘Genovese’: Extra-large leaves with great fragrance and flavour; great pesto basil; originated from the Genoa area of Italy
Ocimum basilicum ‘Sweet Dani’: Very fragrant lemon scent, especially when leaves are rubbed; an All-America Selections winner in 1998
Basil can be difficult to grow from seed. If you enjoy a challenge, start indoors from seed; otherwise, grow from young plants purchased from a garden centre.
How much: Two or three plants; plant up to ten if you intend to make pesto.
When: Two weeks after the average last spring frost date.
Where: Full sun, sheltered. Excellent in containers. Needs rich, well-drained soil. Space plants 30 cm apart in the garden.
Care & Nurture
Basil requires extra care to grow well. Overwatering can cause root-rot. Pinch off shoots to promote robust new growth and a bushy form. Basil tends to get woody when it gets old.
For the most bountiful harvest, prune flowers as soon as they appear. Basil's flavour grows much stronger as the leaves age, losing much of their delicate, sweet scent.
For best flavour: Choose young, small tender leaves for mild aroma and taste. Harvest mid-morning, after the dew has evaporated and before the day gets too hot.
Leaves: Harvest individual leaves by clipping the leaf stalk where it attaches to the plant stem. Cut sprigs and use whole, or strip the leaves. Discard tough stalks.
Flowers: Pick just as flowers emerge. Clip the flower stalk where it attaches to the plant stem; discard stalk.
Preserving the Harvest
The best way to preserve basil is to freeze it: frozen basil retains nearly 100% of its essential oils. Blanch the leaves quickly in boiling water, dry them on paper towel, and freeze them in sealed plastic bags. A short-term way to preserve basil is in oil. Wash and dry the leaves and then pack them into a clean, dry glass jar. (It's important to use a glass jar, as plastic will leach out the flavour of the leaves.) Sprinkle salt over each layer of leaves, and when the jar is full, fill it with olive oil to cover the leaves. Close the jar with a tight-fitting lid and store in the refrigerator. The leaves will keep for 7 to 10 days.
- Here are some other basil varieties you might like to try:
- Ocimum basilicum minimum ‘Green Globe’ is a very dense, rounded basil with a uniform growth habit.
- Ocimum basilicum ‘Nufar’ is a new sweet basil hybrid that has shown excellent resistance to fusarium; it’s a Genovese-type basil with great fragrance and flavour.
- Ocimum sp. ‘Siam Queen’ was an All-America Selection in 1997; it has deep-purple stems and flowers that contrast with its dark-green leaves, and its flavour is spicy with an anise-licorice scent and flavour.
- Ocimum ‘African Blue’ has a different growth habit and leaf form from sweet basils: its leaves aren’t as smooth and have a slight bluish tone, and the leaf veins, stems, and flowers are purple; it has an unusual flavour with a sweet camphor scent. African Blue is probably the easiest basil to grow indoors because it is not susceptible to fusarium.
- Basil seed often harbours a fungal disease called Fusarium oxysporum. Fusarium affects germination and causes sudden wilting of leaves; the stems turn brown, and the plant eventually topples and dies. The fungus can be caused by both contaminated seeds and soil, and spreads easily through contaminated soil and leaves. There is currently no way to control this disease, but some seed companies are attempting to eliminate fusarium from basil seed.
- Basil is among the least frost-tolerant herbs. Around the greenhouse, we joke that you should never walk by basil with a tray of ice cubes, lest you freeze it. Shadier locations cause the plants to stretch, leaving them weak, gangly, and more susceptible to disease.
- To promote leaf growth, pick off flower shoots as they appear, unless you want to harvest a few flowers, which taste like the leaves, only milder..
- Avoid adding compost to the soil where basil is to be grown: compost tends to increase root rot problems.
- Smaller varieties of basil can be used as edging for garden borders. In pots or hanging baskets, basil can serve as a foil for brightly coloured bedding plants.
- Basil's common name is derived from the Greek word for king—"basilikon." In ancient Greece, only the sovereign was allowed to cut basil with a golden sickle.
- In India, basil is sacred, dedicated to the gods Vishnu and Krishna. It is commonly grown in pots near temples. Recognizing its importance in Indian culture, during the colonial era the British used it to swear oaths upon, much like a Bible.
- Basil is considered a symbol of fertility in Western culture. For example, in Romania, when a young man accepts a sprig of basil from a girl, it signals their engagement. In Italy, when a woman puts a pot of basil on her balcony, it means that she is ready to receive suitors—in fact, basil is referred to as "Kiss Me Nicholas" in some regions of Italy.