Basil is one of the most popular herbs, loved for its fragrant leaves that add flavor to countless dishes, from Italian classics like pesto to Asian curries. But did you know that growing basil indoors is one of the best ways to grow basil? Find out all you need to learn how to look after a basil plant indoors and add flavor to your meals by reading on.
Growing basil indoors is an excellent way to ensure you have fresh herbs all year-round. But to ensure your basil thrives, there are a few essential tips to follow. Everything you need to know about how to look after a basil plant indoors is here to help you cultivate a healthy, lush basil that adds fragrance to your home and flavor to your recipes.
Why Grow Basil Indoors?
There are so many benefits for both you and your basil plant when you learn how to look after a basil plant indoors. Basil is a plant that can thrive inside, and here are just a few of the reasons why growing indoors is so beneficial:
- Year-Round Growth: Unlike outdoor basil, which can die off in winter, indoor plants flourish regardless of the season. It’s an ideal indoor herb garden plant and it flourishes inside in the right conditions.
- Freshness at Your Fingertips: Having a fresh supply of basil for cooking is convenient, cost-effective and you might find yourself creating some incredible dishes if your basil plant inspires you to experiment.
- Pest Control: Growing basil indoors reduces the risk of outdoor pests damaging your plant.
What Kind of Light Does Indoor Basil Need?
Basil loves sunlight and needs at least 6–8 hours of direct sunlight daily. Placing your basil on a south-facing window will provide it with the best lighting. Just be careful not to burn the basil leaves in the summer months when sunlight is stronger. If you don’t have enough natural light, you can use a grow light to supplement sunlight for your basil plant.
What Type of Grow Light is Best for Basil?
LED grow lights are ideal for growing basil indoors because they emit the right spectrum of light for photosynthesis without producing excessive heat. Ensure the light is positioned 10–12 inches above your basil for the best growth for about 10-12 hours a day.
What Temperature is Best for Basil Indoors?
Basil plants like warm temperatures, which is why they flourish in a home environment. Temperatures of 65–80°F (18–27°C) are best. Avoid placing your basil in drafty areas, near cold windows, or next to heat sources like radiators. Basil is sensitive to temperature changes, and cold drafts can cause leaves to wilt or turn black (this would normally mean the temperature is dropping below 40F.
How Often Should You Water an Indoor Basil Plant?
Basil needs moist soil when potted in containers indoors for it to grow well and will need watering frequently. Here is how often you should water your basil:
- Water when the top inch of soil is dry. Stick your finger into the soil to check moisture levels.
- Avoid waterlogging the soil. Basil roots can rot in standing water. Ensure your pot has drainage holes and that excess water drains away.
- Water from the base, using a saucer, to encourage deep root growth, but you can also water gently from the top if the surface is too dry.
What Happens If You Overwater Basil?
Overwatering can cause root rot, yellowing leaves, and a wilting basil plant. If you suspect overwatering, reduce the amount of water and let the soil dry out between watering.
What Type of Soil is Best for Indoor Basil?
Well-draining, nutrient-rich soil is key to growing healthy basil indoors. Use a high-quality potting mix that contains perlite or vermiculite. Perlite and vermiculite help with drainage and are good for aeration. Avoid heavy garden soils that may retain too much moisture and cause poor drainage leading to the perfect conditions for mould growing on your plant.
How to Fertilize Indoor Basil
Use a balanced, water-soluble fertilizer (such as a 10-10-10 mix) once a month to promote healthy leaf growth. Dilute the fertilizer to half-strength to avoid over-fertilizing, which can cause basil leaves to lose flavor.
Can You Use Organic Fertilizers for Basil?
Yes. An organic fertilizer like coffee grounds is an excellent natural and budget friendly alternative for your basil plant. They slowly release essential nutrients, supporting long-term healthy growth.
How to Prune Basil for Maximum Growth
Pruning basil regularly encourages bushier growth and prevents the plant from becoming leggy. You can use your hands to break off the leaves, or some herb snippers if you want to take off some of the stem too.
- Pinch off the tops of the basil plant when it reaches 6-8 inches in height if you are looking to encourage bushy outward growth rather than upward growth. Cut the stem using snippers about ¼ inch above where there is new growth with small leaves. This encourages the basil to grow new branches and keeps your basil small and bushy. Always use your snippers for a clean cut.
- Remove flower buds as soon as they appear. Flowering diverts energy from leaf production, making the older leaves taste bitter.
- Harvest leaves regularly by cutting just above a leaf node (the point where leaves grow from the stem). This encourages new growth and ensures continuous harvests.
How to Harvest Basil Leaves
One of the best parts of being a plant parent and learning how to look after a basil plant indoors is when you have grown your basil to the point you can pick the leaves. It’s a wonderful moment that first time you pinch some leaves and add it to your cooking knowing this is a herb you have grown.
For the best flavor, harvest basil leaves in the morning when the essential oils are most concentrated. Pick leaves from the top, leaving at least 3–4 sets of leaves below to allow the plant to continue growing. Never harvest more than one-third of the plant at a time, as this can stress the plant.
Common Indoor Basil Problems and Solutions
Indoor basil plants are relatively easy to care for, but there are some common issues to watch for:
Yellowing Leaves at the bottom of your basil
If the leaves at the bottom of your plant begin to yellow this can suggest overwatering and that root rot is setting in. When you over water a basil plant you remove too much nitrogen from the soil which is what leads to yellowing leaves. (Yellowing leaves can also be a sign of other problems too, so take a good look at your basil plant for other signs and symptoms).
Solution: Adjust your watering schedule, consider removing some of the wet soil on the top and replacing with dry soil and add a bit of fertiliser to help correct the nitrogen imbalance. You cannot get the yellowing leaves to return to being green again once they have yellowed.
Leggy Growth
This common problem is caused by inadequate light.
Solution: Provide more light for your basil or use a grow light. Prune your basil if it is leggy to then encourage it to grow back fuller. You will likely need to prune it more than once after regrowth to get the desired small and bushy result for your plant.
Wilting and black spots
In a lot of cases wilting and black spots on the leaves of your basil plant is caused by downy mildew, but it can also be caused by overwatering, underwatering, or even a pest problem.
Solution: Adjust watering and move the plant to a warmer location. Inspect your plant for other signs of a pest problem.
If it is downy mildew, you will notice your plant has shown signs that tend to spread from the bottom up. If you look on the underside of your basil leaves you will notice a blacky / purple spotty pattern of spores. Always inspect bottom leaves first if you suspect this. Sadly, there is not a lot you can do for your plant once it gets this condition.
Aphids
If you get an aphid infestation on your basil plant, you will likely be able to see these small flies. You may also notice a dust in the centre of your leaves as aphids shed their skin.
Solution: An insecticidal soap can be used to control these pests.
Best Basil Varieties for Indoor Growing
Some of the best varieties of basil to grow indoors are:
- Sweet Basil: The most common variety used in cooking, as it can stand slightly higher temperatures when cooking.
- Genovese Basil: Known for its large leaves and strong flavor, this thin stemmed variety of basil is perfect to grow for pesto-lovers. After only a month of growing you’ll have that glorious basil smell.
- Greek Basil: A compact variety with small leaves, great for small pots. This variety of basil will grow bushier than sweet basil.
- Lemon Basil: Offers a citrusy aroma and is perfect for adding a fresh zing to dishes.
Can You Grow Basil Indoors All Year Round?
Yes, with the right care, basil can thrive indoors all year long. Ensure it gets enough light, warmth, and regular pruning to keep the plant productive even during winter months.
How Long Will an Indoor Basil Plant Last?
Basil is a short-lived perennial which means it has a life span and will eventually die. Basil can last anywhere from 4 months to a year with proper care in an indoor environment, maybe even a bit longer. To extend your basil’s life, consider propagating new plants from cuttings.
Propagating Basil: How to Grow New Plants from Cuttings
Propagating basil is easy and ensures you have a constant supply of fresh plants. Here’s a quick how-to:
- Cut a 4-inch piece from the top of a healthy basil plant.
- Remove the lower leaves from the cutting, leaving only a few at the top.
- Place the cutting in a glass of water on a sunny windowsill.
- Change the water every few days. Roots should begin to form within 1–2 weeks.
- Once roots are 2 inches long, plant the cutting in a pot with fresh potting soil and keep it moist.
Final Thoughts on Growing Basil Indoors
Learning how to look after a basil plant indoors can be incredibly rewarding. With the right balance of light, water, and warmth, you’ll have a beautiful plant with deliciously fragrant leaves you can enjoy cooking with. Keeping a thriving basil plant indoors is a joy, and if you love the flavour you’ll be able to experiment in your cooking with this aromatic herb.
