Growing Thai Basil Indoors: Propagation and Plant Care!

Are you planning on growing Thai basil indoors? Then don’t think twice! This herb can easily grow inside, just like its mother—the common basil.

Thai basil is a resilient and easy-going type of basil. Many gardeners think growing Thai basil to be much simpler than growing other basil varieties.

Even so, every single plant requires care and attention. And our Thai basil is no exception. Proper plant maintenance for Thai basil includes watering, feeding, and pruning.

This guide will help you discover how to do all that and more. This article will help you through the steps of propagating and caring for Thai basil indoors.

Just wait until you finish reading! You will feel confident and ready to grow your own Thai basil indoors.

Propagating Thai Basil

You can propagate Thai basil from seeds or cuttings. We will show you both ways here.

You can skip this first step if you plan on buying an established plant or already have Thai basil.

Growing Thai Basil from Seeds

Propagating Thai basil is both easy and inexpensive. Seeds are usually cheap and can be found just about anywhere.

Bear in mind that this isn’t the most effective method of growing this herb.

Most often, Thai basil seeds have a pretty low germination rate. That doesn’t mean you can’t succeed in growing Thai basil from seeds. (Or else we wouldn’t have mentioned that here!)

All that means is you’ll need to do a bit more work and add more resources to increase the likelihood of your success.

growing thai basil indoors
  • Obtaining the Seeds

The success of this operation will largely depend on how good your seeds are. This is why we always tell people to go for higher-quality brands of seeds.

Many factors will determine their germination rate. You must consider your seeds’ cultivation, storage, and age.

For example, say you stored the seeds in an imbalanced environment for a long time. They will have zero chance of germinating.

To avoid such problems, inspect the seeds’ quality before purchasing them. Seed inspection is the best and simplest way of doing this. Pick the brand of seeds with the most positive online reviews.

  • Obtaining the Medium

Using any random type of soil to propagate your Thai basil is a very risky thing to do.

Growing your seeds in garden soil is a huge mistake. But using potting soil isn’t the best thing to do either.

When propagating Thai basil, there is one main concern. Avoid putting your seeds at risk of contracting a disease.

Some soils are brimming with harmful pests and pathogens. They can prevent seeds from germinating or producing healthy seedlings.

To combat this, experts recommend using a seed-starting mix. They are well-drained and sterile soilless mixes.

Seed-starting mixes are composed of various materials. They drain water efficiently, thus preventing seeds from rotting.

From experience, we can tell you that Black Gold Seedling Mix is one of the best blends you can use for Thai basil seeds. You can find it here on Amazon:

Black Gold Seedling Mix

  • Sowing the Seeds

Prepare the seed-starting mix by moistening it with warm water. Be careful as to the amount of water you put in. The mixture shouldn’t become too soggy.

Next comes your containers. You can buy some seed-starting trays. You can also reuse everyday items you may already have at home, such as milk or juice cartons.

Any shallow containers can work, but be sure to create enough drainage holes. 

Fill your containers to the rim with the moistened mix. Sow your seeds on top of them, and Use four to five seeds for each 1.5 x 1.5-inch container.

growing thai basil

Once completed, cover your seeds with a quarter-inch of soil. Then spray them with water, and place a plastic wrap over the containers.

  • Caring for the Seeds

Keep your seeds in a warm place, away from the reach of intense direct sunlight.

Let the seeds breathe by uncovering the plastic wrap for a few hours each day. Spray the mix with water. You want to keep the humidity levels around your seeds as high as possible.

After a week or two, your seeds will germinate. At that point, the seedlings will be ready to move to different pots.

Growing Thai Basil from Cuttings

Growing Thai basil from cuttings is much more effective than from seeds. In our opinion, it’s easier too.

There is one drawback here. You will need to have a fully established Thai basil plant from which you can get your cuttings.

You might be lucky enough to have a friend or relative who grows Thai basil. In that case, you may be able to ask them to bless you with some cuttings.

If not, no problem. You can buy a Thai basil plant from a nursery and wait until it grows old enough to produce some cuttings.

  • When and How to Take Thai Basil Cuttings

Knowing when to take your Thai basil cuttings is a simple decision. Wait until the plant has grown at least four inches tall. Another recommendation is to wait until it has developed no less than four sets of leaves on most of its branches.

In this condition, your cuttings will be strong enough to start rooting. Then they will become independent plants.

Pick any stem you wish, but ensure it’s healthy and strong. Count three or four sets of leaves—starting from the top—then produce a cut just below the last one.

Note: Avoid waiting until the plant has flowering buds to take your cuttings.

  • Propagating the Cutting

Remove all the leaves at the bottom of the cutting and keep two sets of leaves growing at the top.

After, you should immerse the cutting in a glass of water. Keep it away from direct sunlight. And be sure to change the water every other day.

After two to three weeks, the cutting will grow a well-developed root system. Now you can move it to a pot to grow into a plant.

Note: Once you have moved the cutting to its own pot, you must keep it away from light for 48 hours so as not to stunt its growth.

Caring for Thai Basil Indoors

When it comes to success in growing Thai basil indoors, it all depends on how well you look after the plant.

Here, I’ll discuss all the factors for the survival and development of Thai basil inside. That way, you will be prepared to care for the plant.

Soil and Nutrition

The medium of your Thai basil is one of the most critical factors in its development. The medium is especially important if you’ve potted the plant.

Choosing the ideal soil for your Thai basil is imperative. That will improve the chances of survival, growth rate, flavor, immunity to disease, and much more.

Practices have shown that Thai basil grows best in moderately well-drained and rich soil.

We recommend the popular Foxfarm Ocean Forest® Potting Soil. It has those exact properties and is more than suitable for your plant.

Foxfarm Potting Soil

  • soil

Still, in some cases, the plant may not grow so well in its potting soil.

If this is the case, you have two options depending on your needs. You can adjust the soil’s drainage by adding water-trapping material, such as vermiculite. If your plant is too wet, add a water-draining material, such as perlite.

At the same time, you can’t leave your Thai basil without feeding it regularly.

You need to fertilize and amend the soil (after you change it) every two to three months.

You can use vermicompost, Alfalfa meal, kelp, or another natural fertilizer.

Light

Light is probably the most controversial and complicated issue regarding growing indoor herbs.

Here’s something even more disturbing. Mature Thai basil requires extended periods of exposure to direct sunlight to flourish.

Thai basil

You must find a sunny location indoors, providing at least six hours of direct sunlight. If you are unable, don’t give up on growing Thai basil too quickly! We live in the age of technology and innovative solutions!

That’s why a scientist invented and optimized grow lights. He wanted to help you grow your favorite plants and herbs inside your home.

For example, full-spectrum LEDs or fluorescent lamps are best suited for your Thai basil.

All that considered, you can grow your Thai basil entirely under grow lamps. But it’s better to make the most of the sunlight through your windows.

In other words, aim for a combination of sunlight and artificial light to satisfy your Thai basil needs.

Remember, six hours of sunlight is equivalent to 12-14 hours of artificial light.

So, let’s say your basil plant is getting four hours of light from the sun. You should aid it with an additional four to eight hours of light from your grow lamp.

Temperature and Humidity

Because you’re growing your Thai basil indoors, things are a little more complicated. You must be extra careful about the temperature and humidity levels. These factors could leave your plant in fluctuating conditions.

A temperature around 75°F (24°C) during the day is optimal for Thai basil. That temperature should then drop overnight to around 68°F (20°C).

It’s better to avoid growing Thai basil at a temperature below 68°F (20°C) during the day and 64.5°F (18°C) during the night.

With humidity, it’s preferable to keep the moisture levels in the atmosphere at around 40-50%.

You can measure the humidity levels in your home by using a hygrometer.

You can use an air conditioner, radiator, humidifier, or dehumidifier to adjust the temperature and humidity.

Watering

Watering Thai basil in pots is vastly different from watering it in the garden. This is where all the mistakes can happen.

When it comes to growing this herb, there are two key issues. People overwater or underwater their plants.

One of the biggest problems is that people stick to a watering schedule. Unfortunately, it is usually unsuitable for Thai basil’s growth.

For example, you can’t water this herb daily if the temperature isn’t high. In hot weather, you might need to water Thai basil twice daily.

The best way to know when to water your Thai basil is by simply monitoring the soil on a daily basis. Just use your finger to feel the soil in the container every day.

Water your Thai basil when the soil becomes dry. This way, you can ensure you’re giving your plant the optimal amount of water. 

Pruning

Pruning is one of the most important activities in herb gardening. Your Thai basil’s productivity greatly depends on pruning.

The good news is that this plant is pruned the same as common basil.

If you don’t know how to cut back basil, you can learn about it in this article on pruning basil!

Transplanting

Thai basil’s roots grow almost at the same rate as its leaves and stems do. If the pot isn’t big enough, at some point, your plant’s roots will bump into the wall of the container.

If your Thai basil is rootbound for too long, it might die. In this instance, transplanting your plant to a wider pot is crucial.

And that’s it! Enjoy cultivating your Thai basil. And don’t forget to share your thoughts and experiences in the comments below!

Additional resources: How to Grow Basil Indoors Year Round! (TheGreenPinky.com)

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2 thoughts on “Growing Thai Basil Indoors: Propagation and Plant Care!”

  1. My Thai Basil plants their stems are all turning black! What’s the reason? I had to bring them inside because of the cold weather & I do not water them as much as I did when they were outside! Please help?

    • I believe this is a case of root or stem rot that is most likely caused by a fungal disease due to lack of proper drainage and/or ventilation. It might be already too late to save the plant but try to remove the affected stems as soon as possible.
      Good luck!

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