Days to germination: 7 to 10 days
Days to harvest: Throughout the season
Light requirements: Full sun
Water requirements: Regular watering
Soil: Well-drained and loose
Container: Yes, indoors and outdoors
Like most herbs, basil is grown for its aromatic leaves. Whole leaves can be added to summer salads but basil is more often used to season Italian tomato sauces or to make pesto. The dark green leaves are high in vitamin K, and are also a fair source of calcium and iron.
Basil plants are annuals, so if you plan on growing it outdoors, you will have to re-seed each year to keep your herbs growing. Or grow it indoors.
There are many kinds of basil, each with its own subtle flavour traits. The most commonly grown is called sweet basil. Lemon basil and Zulu basil both have a lemon-citrus flavor, and Thai basil tastes a little bit like black licorice. Some varieties of basil are purely ornamental, like Purple Ruffles.
Starting from Seed
Basil cannot tolerate frosts, so if you are going to plant seeds, they can’t go into the ground until after all threat of frost is past. Or you can start your seeds indoors about 2 weeks before your last frost date, and transplant the seedlings out a week or 2 after your frost date.
Plant your seeds indoors in seedling pots, under about half an inch of potting soil and keep it moist. If you are going to keep your plants indoors, then you can plant your seeds directly into your final larger pot.
Keep your growing seedlings in a very sunny location or your plants will get spindly.
For growing basil outdoors in the garden, space your seedling approximately 10 to 12 inches apart. If you are planting seeds, keep to the same spacing, and cover then with 1/2 inch of soil.
Before planting, dig up your soil to loosen it well and add some extra compost or aged manure.
Choose a place for your plants that will get full sun throughout the day, but also be somewhat sheltered from hard winds.
To keep your plants bushy and producing the leaves you want to harvest, pinch out the top leaves once your plants get to about 6 inches high. Also pinch out or clip any flowers that start to form later in the summer. If you let the flowers go to seed, your plants will lose much of their flavor and leaf production will slow right down.
Also, pinch off the tips of some of the side branches as well. You want your plant to be as leafy as possible rather than tall or spread out. More branches means more leaves to harvest.
Water your basil regularly, and provide your plants with a light fertilizer feeding mid-summer. A standard fertilizer formula is fine. If you have very nutrient-rich soil, they probably won’t need any supplemental feeding at all.
Depending on the variety, your basil plants won’t grow much taller than 2 feet (it also depends on how often you harvest those leaves). Most plants are fairly sturdy and shouldn’t require any staking or support.
Basil grows well indoors if you have a location that provides 7 hours of sunlight each day. The same applies for any potted basil plants you are growing outside.
You can grow one basil plant in a 6-inch pot, or a few plants in a 12-inch pot. The containers should have extra gravel in the bottom to ensure excellent drainage for your basil plants. Water regularly, and give them a feeding once or twice a year.
For outdoor pots, plant your seeds or seedlings at the same time listed in the Starting from Seed section. But if you intend on keeping your basil plants inside, then you can sow your seeds anytime you wish.
Pests and Diseases
Slugs are a typical problem with basil, chewing up the leaves during the night. Set out a shallow saucer of beer to trap and drown them, or use a commercial slug bait to help keep them out of your plants.
Aphids also love basil, and they can even be a problem if you are growing your plants indoors. Spray your plans with insecticidal soap with pyrerthrins to control the tiny aphids. A few of them won’t harm your plants, but a large infestation will soon cause your basil to suffer.
Not a common problem for plants grown indoors, but powdery mildew can effect your outdoor basil plants. A little fungicide spray can help clear it up, but you’ll have to hold off on any harvesting for several days and make sure to wash the leaves well. You can help prevent mildew build-up by not watering your plants all over the leaves. Pour the water carefully at the soil instead.
Harvest and Storage
Over the course of the growing season, you can get up to 10 cups of fresh basil leaves from each plant you grow.
The easiest way to harvest basil is to just take a few leaves from each plant as you need them, without taking more than about a third of the total plant. Harvesting is usually done at the top of the plant, just snipping off the top few branches, stems and leaves for use. The lower part of the plant keeps growing, and produces new shoots to harvest at the top next time.
Make sure your plants is well established before you start plucking leaves off. There should be at least 3 pairs of leaves on the plant before you start to harvest.
You will be able to keep harvesting basil right through the summer until your first hard frost. The plants will die back almost immediately. When you are expecting a frost, harvest your entire plant so that no leaves go to waste. Extra basil stores well.
You can freeze your fresh basil leaves for later use, or hang the leaves to dry for about a week in a warm room. Once they are fully dried, you can keep your basil in an airtight container for a full year.