How to Grow Basil Indoors

closeup of a basil plant

The Spruce / Letícia Almeida 

Basil is one of the easiest herbs to grow indoors, and its delicious flavor and culinary popularity make it a must-have for gardeners and cooks alike. With the proper conditions, basil grown indoors can be just as successful (if not more so) than plants that are grown outdoors.

Though it's traditionally associated with Italian and Mediterranean cooking, basil is actually native to Asia. Best planted in early spring outdoors or year-round indoors, basil will grow quickly, establishing in just three to four weeks. The plant features small, shiny green leaves that grow in bunches and possess a very distinct aroma. Approximately 75 days after planting, your basil may begin to flower—simply snip off the blooms to prolong your plant's vegetative phase.

Botanical Name Ocimum basilicum
Common Name  Basil, sweet basil
Plant Type  Annual
Mature Size  12–24 in. tall, 12–24 in. wide
Sun Exposure  Full Sun
Soil Type  Moist but well-drained
Soil pH  Neutral to acidic
Bloom Time Summer, fall
Flower Color White, pink, purple
Hardiness Zones 2–11 (USDA)
Native Area Asia
overhead angle of a basil plant
The Spruce / Letícia Almeida
Basil
Verywell / Alexandra Shytsman

Basil Care

As with many other herbs, basil is a true sun-lover—give it bright light each day, and it will thrive. Alternatively, basil does exceptionally well under grow lights as well, so you have the opportunity to increase your harvest and grow enough basil to keep your kitchen stocked throughout the year.

Basil is a uniquely rewarding plant to grow—it's relatively pest and disease-free and is delicious in both fragrance and taste. Basil's taste will change throughout its life cycle, becoming stronger as the plant flowers—basil that has flowered can still be eaten, but it may be a bit bitter. The herb responds well to pruning and topping, so feel free to use leaves as soon as the plant is established and has branched out.

Light

Whether being grown indoors or outdoors, basil plants need ample light—at least six hours of full sun daily. If you're using fluorescent bulbs, keep your basil under them for 12 hours a day, with the lights about 2 to 4 inches away from the top of the plants. Be careful not to let the leaves touch the bulbs to prevent burning.

Soil

Basil plants prefer a soil mixture that is moist but well-draining. For best results, amend your potting soil with a bit of organic compost before planting your basil indoors. Beyond that, make sure to choose a pot for your plant that boasts ample drainage holes at its base so the soil doesn't get soggy or waterlogged.

Water

For best results, aim to keep your basil plants regularly moist. Basil thrives best when it receives about an inch of water a week, but plants housed in containers often need even a bit more than that. Water your plant once the top layer of soil has dried out, or when the plant shows the first signs of wilting (though it's best to not wait for that as a signal).

Temperature and Humidity

Keep your basil somewhere in your home that boasts an average temperature of 70 degrees Fahrenheit or higher. Avoid putting the plant anywhere it may be subjected to a harsh or cold breeze, like in front of an open window in the winter or near an air conditioning unit. Basil plants also like a fair bit of humidity, so mist your plant occasionally, especially if your home is particularly dry. If you find you need an added bit of moisture, you can place your basil container on a bed of wet river rocks to increase the ambient humidity around the herb.

Fertilizer

If you've previously amended your soil with organic compost, there's a good chance that your basil plants won't need additional nutrients. However, if you notice your plants aren't experiencing much growth, you can feed your basil plant once a month using a weak liquid fertilizer.

Basil Varieties

There are dozens of types of basil, each of which has its own unique flavor and attributes. Some of the most popular varietals suited to indoor growing include:

  • Ocimum basilicum 'Genovese': Commonly referred to as Italian basil, this varietal has large green leaves and a sweet, quintessential basil flavor.
  • Ocimum basilicum 'Purple': Beloved for its striking rich purple hue, this varietal has pointy leaves and a rich, almost licorice-like flavor.
  • Ocimum basilicum x citriodorum 'Lemon basil': A hybrid plant, this varietal has thinner, more delicate leaves and is very popular in Asian dishes thanks to its distinct citrus taste.

How to Grow Basil From Seed

Basil plants start readily from seed, especially when placed under grow lights. Most basil varieties will germinate in about five days when kept at temperatures around 80 degrees Fahrenheit (a heat mat can be helpful to achieve these conditions as well). Lower temperatures will increase germination time.

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Potting and Repotting Basil

Most people eat their basil before they can repot it. If you're growing from seed, step up seedlings from a seed starting tray after two weeks into a 4-inch pot, which will likely be their final home. Pinch the herb after the newly repotted plant is established to encourage more leaves. Basil responds well to pruning, but don't expect indoor plants to get quite as large as those grown outdoors.