How to Grow Basil Indoors

There’s something refreshing about the summery aroma of basil growing indoors on a windowsill. When you gently brush the plant with your hand, the vibrant scent will quickly fill the air. Plus, having a pot of basil growing in a sunny spot in your kitchen ensures you’ll always have this flavorful herb within easy reach when cooking, no matter the season. Sure, you could purchase potted basil plants from your local garden center or grocery store in spring and summer. But with just a few dollars of seeds and a little bit of your time, here’s how to grow basil indoors year round.

How to Grow Basil Indoors from Seed

Basil is one of the easiest herbs to grow indoors. You can raise this plant from cuttings or seeds. Starting seeds inside gives your seedlings a warm and safe start. You’ll just need to make sure you put the basil plants in your sunniest window (preferably one facing south or east). Follow the steps below to help you grow basil indoors from seed.

1. Plant basil seed at the right time.

Basil is one of the easiest herbs to grow from seed. Read your seed packets to know how many weeks of growth your plants will need before they can be moved outdoors. You can start basil seed indoors and transplant the grown plant outside in rich, well-drained soil once all danger of frost has passed. If you live in a cold or very hot climate, start your herb seeds in early spring so that the young plant gets well established before the summer heat and winter cold. Gardeners who live in a mild climate can transplant seedlings into the garden throughout most of the year.

2. Prepare your pots.

Pre-moisten the soil so it’s slightly damp to help keep your seeds from shifting when you first water them. Then, loosely fill small containers with a high-quality potting soil—commercial starting mixes are sterilized to remove weed seeds and disease-causing microbes. Choose a container or pot that allows for good drainage. If your pot doesn’t have drainage, make some holes in its bottom.

3. Plant, water, and cover the seeds.

Plant the seeds by gently press them into the soil with your finger and then cover lightly with soil (check seed packet for instructions on planting depth). Water the seeds lightly and then cover the pot or container with plastic kitchen wrap or a plastic dome. This will keep the soil mix and seed warm to encourage germination.

4. Provide plenty of light.

Basil grown indoors needs lots of light. Put the container in a sunny area such as near a south-facing window or place them under a grow light, and when the seedlings emerge, remove the plastic wrap or covers. If using grow lights, adjust the height of the fixture as the plants grow to make sure the light bulbs are at least 6 inches above the top of your plants. When growing herbs indoors on a sunny window sill, make sure to give your plant a quarter turn weekly to expose all sides to the sun to make sure the seedlings won’t be spindly and pale.

5. Increase air circulation and humidity.

Place a small fan near your seed starting area to keep air moving and reduce damping off, a common fungal disease. To boost humidity indoors—especially in the wintertime—place the plants on a tray of wet pebbles to raise the humidity around them. Fill the tray with water until the water’s surface is just below each of the pots’ bottoms. Another option is to place a humidifier nearby.

6. Keep seedlings moist.

Once your indoor basil seedlings have started growing, don’t let their soil dry out. It’s important to keep your basil plants well hydrated at this stage to encourage healthy root growth. This will help your plants become larger and more efficient at absorbing water and nutrients from the soil.

7. Harden off plants.

About a week before transplanting your seedlings, gradually acclimate them to outdoor conditions. Begin by putting them outside for a few hours on a warm day in a shady spot to let them get used to the differences in temperature, humidity, and air movement outside. Remember to bring them indoors again at night. Over the next few days, gradually increase the time they spend outdoors. By the end of the week, your plants should be acclimated and ready to be transplanted.

How to Grow Basil Indoors in Water

Another way that you can multiply your basil plants indoors is by rooting them in water. To do this, take your basil plant and cut its stems to 3 to 4 inches long and strip off any leaves that would be under water. Fill a glass with water and place stems in the glass.

As the stems start growing roots, change the water every few days. This helps to discourage bacteria that can create an unhealthy situation for your basil cuttings. Once the roots are about an inch long, transplant the cuttings into fresh potting mix. Keep your new basil plants well watered for the first week or two. Soon you should see new leaves growing, and you can cut back on watering a little.