Tips On How To Plant, Grow And Harvest Thai Basil


Spring is right around the corner, so when you consider planting, you should add Thai Basil to your list. 

You might be familiar with regular basil, which is an herb in the mint family. Basil is an essential herb in Italian dishes, extensively used in tomato-based sauces and the main ingredient in pesto. 

Thai basil is a cousin of regular basil and is a popular herb in its own right. Thai basil is known for its distinctive flavor and appearance. It can hold up better than other basil relatives for culinary uses.

Thai Basil Has A Distinctive Flavor And Beautiful Appearance

You will find that Thai basil has a more robust flavor and aroma than the commonly used sweet basil has. Some describe its taste as similar to anise or that it is licorice-like. Thai basil is also spicier than regular basil.

Like many other herbs, Thai basil is easy to grow indoors as long as you meet its temperature, water, and sunlight needs. 

The plants have small, narrow leaves, dark purple stems, and pink flowers. Because of its striking physical appearance, Thai basil is also grown as an ornamental piece.

Thai basil loves warm conditions and full sun. When outside, they do well in hot summertime temperatures and long days of light. 

Their growth will decline as temperatures drop at the beginning of fall and the daylight hours become shorter. Growth will completely halt in the winter if the plant is outdoors.

Supplies For Growing Thai Basil Indoors


Thai basil indoors is relatively easy, and if you start the plants indoors first, you will get a head start on the season before moving the plants outdoors.

Here are the things that you will need:


You can start Thai basil from seeds or through plant cuttings. Check your local nurseries for seeds and plants. There are several plant catalogs online that would also supply you with plants or seeds.


You can use plastic or clay pots to start your seedlings or use seedling grow bags. The advantage of grow bags is that they take up no space to store, and you can plant the bag right in the ground when the time comes.

Soil or growing media:

There are various potting mixes that you can obtain for growing plants. You can find these mixes at nurseries and even at big box stores like Walmart. Home improvement stores like Home Depot or Lowes also have these mixes in their outdoor sections.

Grow lights:

Any type of plants that you start indoors will need a great amount of sunlight. To get maximum growth and yield, you will need supplemental light, not just the light coming through the window. 

Thai basil does well with fluorescent grow lights or full-spectrum LEDs.

If you choose incandescent light, hang the lights at least 24 inches above the plants. Incandescent gives off a lot of heat, so you have to be careful not to fry your plants. 

If you use fluorescents, keep the lights about 12 inches above the plants. LEDs have a much lower heat signature so that these lights can be hung about 6 inches above plants. 

This lighting placement will be vital if you use shelves to start your plants, as space between the shelves will dictate where you can hang your lights.

How To Grow Thai Basil Indoors

Thai basil is native to the tropical regions of southeast Asia. This type of basil prefers full sun and warm conditions, very similar to regular basil.

When growing Thai basil indoors, you want to mimic the plants' outdoor conditions that the plants grow best in. Provide plenty of light and keep them warm. This will encourage strong, healthy growth and produce the best-tasting foliage.

Keep the temperature warm

Thai basil plants are susceptible to cold temperatures. These plants do best when temperatures are between 72 to 85 degrees. If you start your Thai basil plants from seeds, you will want to keep them away from cold windows and drafts during the winter months.

Starting your seeds or plants with a Waterproof Seedling Heat Mat will give you plants the warmth that they need to germinate and provide a steady, warm environment. 

Even if the temperature takes a short dip down to 50 degrees, as when a door from the outside is opened, it can affect the plants' growth for a length of time afterward. A heat mat will help to provide a constant temperature for the soil the seeds are planted in. 

Provide the light that the plants need

Plants of any type need sunlight to achieve photosynthesis. This process converts carbon dioxide and water into the sugar that plants use as food.

When growing Thai basil indoors, the plants will require a minimum of 6 to 8 hours of sunlight a day. The plants should be in a south-facing window that receives at least that amount of sun. 

If your plant is not getting enough sunlight, it will have poor growth, unusually long stems, and leaves that are smaller than usual. They may also be pale in color or begin to turn yellow. 

If you don't have a window that gets at least 6 hours, preferably 8 to 10 hours, of sunlight each day, consider getting a grow light like the ones we mentioned earlier. 

By using a grow light, you will never have to concern yourself if you have grey or overcast days. You can simply let the grow lights do their job.

How To Plant Thai Basil Seeds

Because basil is a heat-loving plant, don't put your germinated plants in the ground before the outdoor soil temperature is between 65 to 70 degrees. 

A 50-degree night will affect the plant's growth adversely, so make sure that temperatures at night are warm. Start the seedlings about three to four weeks before you plant them outdoors.

Here is how to start Thai basil from seeds:

  • Fill your containers with a potting mix that you have moistened.
  • Place four to six seeds per pot on the top of the soil, mix and cover them lightly with the mixture.
  • Place your containers where the plants will be in at least 70-degree temps at all times.
  • Keep the soil moist but not overly wet.
  • As the plants grow, thin them when they reach a couple of inches tall. Choose the single best-looking plant per 6-inch container and leave it to grow.

Tips for Caring For Your Thai Basil Plants

  • Water the containers when the potting soil is dry to the touch.
  • Water the soil directly and avoid getting the water on the foliage
  • Fertilize the plants every 4 - 6 weeks using a water-soluble fertilizer at half strength. If you are planting your basil outside, you will not need to do this step.

Harvesting Your Thai Basil Plants

Thai basil responds well to harvesting. When you regularly remove foliage, it triggers new growth on the plant.

  • It is best to harvest mid-morning on a sunny day. This is when essential oils in the plant are at their peak.
  • Use clean, sharp scissors or your fingernails.
  • Snip or cut off stems right above the node where a pair of leaves originates.
  • Pinch off branch tips regularly to encourage your plant to grow outward for a fuller shape.
  • For the best flavor, harvest the leaves before the plant flowers.

In Conclusion

Thai basil will add a variety of flavors to your culinary dishes, and the plant will look good as it does so. These plants are low maintenance, easy to grow, and will reward you with great tasting, lush and aromatic foliage.