Basil is easy to grow, but it only grows outdoors in the summer once the soil has warmed up nicely—and it’s a great companion to tomatoes! Here’s what to know about planting, growing, and harvesting basil.
A member of the mint family (Lamiaceae), basil is one of the most popular culinary herbs. It’s a warm-weather annual herb you can plant outdoors once temperatures are consistently above 50°F.
Basil is not usually seeded directly into the soil; typically, gardeners transplant small starter plants purchased at a nursery. Or, they may start the seeds themselves indoors under grow lights.
Common or sweet basil, Ocimum basilicum, is the most common basil; other types include purple basil (less sweet than common basil), lemon basil (lemon flavor), and Thai basil (licorice flavor)
If you’re planning on making pesto, grow several plants. For other uses, one or two basil plants yield plenty.
Basil will grow best in a location that gets 6 to 8 hours of full sun daily, though it can perform well in partial sun, too.
Soil should be moderately fertile and moist but well-draining. Basil works great in containers or raised beds, as these allow for better drainage. The pH of the soil should ideally be in the range of 6.0 to 7.5 (slightly acidic to neutral).
If you plan on cooking with these plants, plant in clean soil, don’t use insecticides, and grow them away from driveways and busy streets so exhaust won’t settle on the plants.
When to Plant Basil
To get a jump on the season, start the seeds indoors 6 to 8 weeks before transplanting outside. (See local frost dates.)
To plant outside, wait until the soil has warmed to at least 50°F (10°C)—preferably around 70ºF (21°C) for best growth. Nighttime temperatures shouldn’t drop below 50°F (10°C).
Don’t rush basil. Without heat, the plant won’t grow well!
How to Plant Basil
If you are sowing seeds directly into the ground sow no more than 1/4-inch deep. Seeds should germinate within 5 to 7 days. Once they have developed 2 to 3 pairs of true leaves, transplant.
If you are planting the germinated seedlings or starter plants in the ground, space 10 to 12 inches apart. Basil should grow to about 12 to 24 inches in height.
A 2- to 3-inch mulch of compost or ground-up leaves retains soil moisture and minimizes weeds around the plants.
Tomatoes make great neighbors for basil plants in the garden—and on the plate—so many gardeners will plant the two warm-weather friends around the same time.
How to Grow Basil
Make sure that the soil is moist. Basil plants like moisture.
If you live in a hot area, use mulch around the plants (the mulch will help hold in moisture and suppress weeds).
During the dry periods in summer, water the plants freely.
After the seedlings have produced their first six leaves, prune above the second set. This encourages the plants to start branching, resulting in more leaves for harvest.
Every time a branch has six to eight leaves, repeat pruning the branches back to their first set of leaves.
Fertilize sparingly throughout the season with a 5-10-5 fertilizer.
After about 6 weeks, pinch off the center shoot to prevent early flowering. If flowers do grow, just cut them off.
If the weather is going to be cold or if a sudden frost is imminent, be sure to harvest your basil beforehand, as the cold temperatures will destroy your plants.
Cinnamon basil, to add a hint of cinnamon to a dish
Purple basil, to add some nice color to your garden (when steeped in white vinegar, it creates a beautiful color)
Thai basil, to add a sweet licorice flavor to a dish.
Start picking the leaves of basil as soon as the plants are 6 to 8 inches tall.
Once temperatures hit 80°F (27°C), basil will really start leafing out.
Harvest in the early morning, when leaves are at their juiciest.
Make sure to pick the leaves regularly to encourage growth throughout the summer.
Even if you don’t need the leaves, pick them to keep the plant going. Store them for later use!
If you pick regularly, twelve basil plants can produce 4 to 6 cups of leaves per week.
How to Store Basil
The best method for storing basil is freezing. Freezing will prevent the plant from losing a good portion of its flavor. To quick-freeze basil, package whole or chopped leaves in airtight, resealable plastic bags, then place in the freezer.
Another storage method is drying the basil (although some flavor will be lost). Pinch off the leaves at the stem and place them in a well-ventilated and shady area. After 3 to 4 days, if the plants are not completely dry, place them in the oven on the lowest heat setting with the door slightly open. Remember to turn the leaves (for equal drying) and check them frequently. See more about drying basil, tomatoes, and paprika.
Wit and Wisdom
Basil has a lovely fragrance. Pick from the stems and put in water for a few days as you would with cut flowers!