When you understand how to grow basil indoors, you will never have to buy another basil plant.
We grow basil year-round, and so can you. Regardless of your level of expertise, you can follow our guide to have fresh basil on tap year-round.
This article will focus on caring for and growing basil plants indoors. We will cover every step, from sprouting the first leaves to harvesting this wonderfully aromatic herb for use in salads, pesto, seafood dishes, pizza, vegetable soups, and so on.
Starting basil from seeds is the most common - and traditional method - to grow basil. But indoor basil can also be grown from cuttings and is - along side lettuce - the ideal choice if you are interested in learning about hydroponics.
Growing basil plants indoors
Growing basil indoors is in many ways similar to growing basil outdoors. There are, however, two main differences.
On the plus side, the indoor growing season is year-round as long as you can find a way to compensate for the lack of direct sunlight during the dark times of the year.
But this longer growing season also means you must use a grow light to overcome the lack of natural sunlight for the darker periods of the year.
Basil wants fertile soil that drains well. And always use a pot with drain holes made from a material that breathes like terra cotta.
Find detailed guides on how to grow basil and Thai basil in the article archives. You can alos use soil less potting soil mixes like coconut coir to start basil from seed.
Step 1: Waiting for basil seeds to germinate and sprout
Basil seeds are delicate; you should avoid top watering using a regular watering can. Instead, mist the pot using a spray bottle or bottom water your pots.
Covering the pots with clear plastic is an effective way to ensure moist soil.
When bottom watering, remove the pot when the dry soil has absorbed enough moisture, indicated by a change to a darker soil color. Next, let the pots drain any excess water. It is vital to keep the soil moist but not wet.
Basil seeds germinate within a week or so and do not need any fertilizer to sprout.
Step 2: Even a sprouting basil plant needs light to thrive
When you see the first leaves, remove the cover and place the pots in a spot with sufficient light.
Basil needs at least 6 hours of natural sunlight to grow and thrive. And as soon as the seeds germinate and you see the formation of the first leaves, you need to get your lighting in order.
Growing basil indoors, you have two choices:
- Place the young seedlings in a south-facing window with sufficient natural light
- Use a grow light to give your basil pants enough light
We use grow lights during the darker periods of the year. Always check the heat generated by your grow light fixture before finalizing the grow light placement.
But as a rule, placing grow lights closer to your plants will have more effect.
Needless to say a south facing window will only give sufficient light if you live in the northern hemisphere. Should you instead live in the southern hemisphere, place your pots in a north facing window.
Step 3: Transplanting basil seedlings into a larger pot
It is time to pot up or repot your basil seedlings when they have developed at least two pairs of true leaves.
When possible, I do not prick out the seedlings but transplant the whole starter pot into a larger pot.
Basil plants do not like cold temperatures or windy conditions. Keep the temperature between 23-28 degrees Celsius (73-83 F) when growing basil indoors.
Be mindful of windows with a draft during winter when growing basil indoors. In cold temperatures below 10 degrees Celsius (50 F), your basil plant will suffer and might even die.
Basil does not take well to dry soil, so soil amendments that help maintain a constant moisture level are helpful. Adding peat moss or vermiculite can help keep the soil moist.
Ensure you provide sufficient light for your basil plants to grow robust and compact.
I like my basil plants to grow large and bushy. If needed I thin out weaker plants - and they do make for delicious eating.
Step 4: Harvesting basil plants is key
When you grow basil indoors, you want compact and bushy plants. And here, the key is to harvest your plants continuously.
Continuous harvesting helps stimulate new growth and allows the basil plants to grow bushy. Always use sharp and clean scissors and harvest outside-in when harvesting individual leaves.
Why not harvest branches and use the stem cuttings form to use for growing even more plants? Using stem cuttings is a fast and very effective method of growing basil indoors.
Step 5: Basil plants and choice of fertilizer
Continuous harvesting will stimulate the basil plant to grow stronger. But your basil plants will need the energy to produce leaves for you to harvest.
I recommend adding an organic fertilizer starting after your first harvest. Basil responds well to liquid fertilizers.
As always, start with half the recommended dosage to one plant and observe the effect to minimize the risk of shocking your basil plants. You can always add, but it isn’t effortless to balance overfertilized soil.
When you have found a balance that works for your plants, you should add the same organic fertilizer every 4-6 weeks.
Step 6: Prune and care for your basil plants
Basil plants grow well and keep producing new healthy growth for you to harvest as long as you
- provide fertile soil that drains well
- ensure plants have sufficient light
- maintain moist – but not wet – soil
- prune and harvest your plants regularly
Basil must be regularly pruned to help the plant grow bushy and compact. After about six months, your basil plants may decide to flower, produce seeds and die off.
By pruning flower stalks and topping your plant, you can successfully extend the lifespan of your plants for several weeks.
You will know when it is too late to save your plant as the stems grow woody and the basil leaves grow yellow.
Best basil varieties to grow indoors
There are numerous basil varieties to choose from. It isn’t easy to crown the best type to grow. But from all the varieties we have grown over the years, these 3 are my favorites:
- Common, sweet, or Genovese basil – large aromatic leaves, perfect for salads, sublime with tomatoes, ideal for pesto
- Thai basil – sturdy aniseed-flavored leaves, great in salads, stir-fry’s, or cooked with chicken or tofu
- Opal basil – purple leaves, sweater taste, great for infusing vinegar and oils, favorite with pasta dishes
Summary: Growing basil indoors
Basil is probably the most popular aromatic herb grown by home gardeners. And it is easy to understand why. Basil is such a versatile herb. Take the basil, add tomato slices and mozzarella cheese, and sprinkle a good quality olive oil on top and you have a Michelin-star quality dish.
And if you only take one thing from this article, please let it be that basil and indoor gardening generally require more hours of light than you will get naturally.
If your basil leaves show signs of yellowing or lack of new growth, you should look at the plants’ exposure to light.
