Growing Basil Indoors and Outdoors 2025

“The traditional way is to have an indoor seed starting kit, which consists of a seed pod, basil seed, and covered container to trap moisture and humidity,” says Weiss. If your home stays fairly warm (above 70 degrees) all day long, great; if not, you may want to invest in a heat mat or grow light to help aid the sprouting process. “Basil needs heat, light, and water to live,” Weiss says. “Heat warms the soil and accelerates the germination and gets a higher level of germination. You can also use a plastic dome that goes on top of your seeding tray and creates a miniature greenhouse-like environment.”

Once your seeds have sprouted, at least 1/3 of an inch or so, says Weiss, you can remove the dome, grow light, or heat mat and let the natural sunlight take over. The basil plant will continue to grow, resulting in a mature plant that’s ready to be moved to its main container or garden bed.

Weiss recommends starting the basil-growing process in late spring or early June if you’re beginning from seeds. For the best results, start your basil seeds indoors using a seed kit before moving the plant to its final location in the garden. However, if you’ve purchased a fully grown basil plant, you can place it directly in the ground or in a container when the outdoor soil temperature is consistently 70 degrees Fahrenheit or higher. Planting outdoors too early can expose your basil plant to risks like excess rain, cold, and overnight freezing.

Once the outdoor basil plant is situated among other warm-weather edible plants like tomatoes, peppers, and zucchini, it should be easy to care for—the warm sunlight of the summer season provides ideal conditions for growth.

Sunlight

Basil is a light-loving and heat-tolerant plant that requires full exposure, which is six to eight hours of sunlight per day. In the summer months, this is doable in almost any yard or garden bed. Just be sure to not place your basil under a shady tree or next to a taller plant that could block its light.

Soil and Fertilizer

Basil prefers to be grown in potting soil or a potting mix, even outdoors. Weiss explains that most traditional gardening soils don’t contain the necessary nutrients for basil to grow at its full potential.

Water

“It’s a delicate dance of how to water your basil,” says Weiss. “The plant prefers being moist, but it’s also prone to root rot, so soggy soil can damage the plant overall.” If you stick your finger one inch into the pot and can see soil clinging to your finger after you pull it out, you know it’s moist—so don’t water it.

Pay attention to the forecast as well. If it’s hot and dry, in the 70s or above, you can water your basil plant every two to three days. When there are periods of rain, you can pause your watering schedule until the soil dries out a bit.

Planter Size

For potted basil, be sure to look out for signs that the plant is outgrowing its outdoor container. Stunted growth or roots emerging from the top or bottom are signs that it’s time to upgrade your planter size.

Sunlight

When growing basil indoors, keep in mind that it requires six to eight hours of sunlight per day—placing it in a south-facing window is best. For all other indoor light levels, you’ll want to supplement the lack of natural light with grow lights.

Soil and Fertilizer

Similar to outdoors, you’ll want to plant your mature basil or seeds in a potting mix or soil to ensure it receives the proper nutrients.

“Gardening soil is much more compact than potting soil, which means roots can’t develop as easily or as deeply,” explains Weiss. For fertilizer, Weiss says to choose a liquid concentrate and provide the plant with a few drops once a month during the peak growing months (late spring to early fall). Add too much fertilizer and the plant will focus on growing its stem, which results in smaller leaves.

Water

Basil prefers to stay moist, but never soggy. Rather than wait for the soil to dry out completely, like you would with most houseplants, Weiss recommends watering again when the soil feels mostly dry, but not crumbly.

Planter Size

If you plan on growing basil indoors, always opt for a larger container than you think you’ll need.

“The soil tends to dry out faster [in a small container] because there is less of it to hold water,” explains Weiss. “A larger pot also allows the roots to spread out and take a firmer hold.”

If there’s one rule Weiss has for harvesting basil leaves, it’s to pick from the bottom up.

“The bottom leaves are, of course, bigger,” he says. “But this also allows for the plant to direct its energy toward the newer growth up top.” Using scissors, or just your fingers, carefully pinch and tear off the largest basil leaves from the bottom of the plant. Then, wash your leaves and they’ll be ready to add to whatever dish is on the menu.

Basil does not require pruning for maintenance after the first few weeks. However, you’ll want to snip off any flowers that emerge for larger, healthier leaves.

Basil plants can take anywhere from a few weeks to two months to create leaves when grown from seeds. The germination process is quick, usually a week or two, but it’s important to be patient and not pluck the first greens you see. Weiss recommends not harvesting until there are plenty of leaves left to continue growing, which is usually between two and three months from seed.

On the other hand, a mature basil plant purchased from a garden center can be harvested immediately, just remember to pick from the bottom leaves up.

Flowering

Once a basil plant reaches a certain height (anywhere from one foot to three feet tall, says Weiss), flowers will start to bud and bloom.

“You want to prevent flowering because that’s when the growth of the basil is going to stop, and it’s gonna go into the flower,” explains Weiss. “What you want to do is use a pair of scissors to snip off each flower to avoid the stalk from becoming very condensed.”

Too Leggy

A healthy basil plant looks more like a bush than a stalk, explains Weiss. To help your plant grow wider, pinch off the top section of leaves once a week for the first few weeks of active growth after planting it in its final location. This encourages the plant to direct its energy outward instead of upward.

Not Growing

If your basil plant isn’t growing at all, Weiss recommends patience.

“Basil plants don’t like change in their environment,” he says. “If your plant isn’t growing for a few weeks, let the plant adjust, so it can go through a bit of shock or an acclimation period. Maintain your normal care routine throughout this time.”

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Adam Weiss is a master gardener and founder of Pike Lane Gardens in Woodstock, New York. With 23 years of gardening experience, Adam is passionate about teaching his craft to others. He’s contributed to publications such as Men’s Journal, Food Management, and Happily.com. He has also taught adult education courses at Bard College and hosted a weekly radio segment, “In the Garden with Adam,” on WDST, Radio Woodstock.