Basil with purple flowers

Thai Basil

Light requirements: Full sun is ideal, but plants can grow in part shade.

Planting: Space 8 to 18 inches apart, depending on type. (Read the stick tag that comes with the plant for specific spacing recommendations.)

Soil requirements: Plants grow best in rich, moist but well-drained soil with a pH of 6.0 to 7.0. Work organic matter into soil before planting to add fertility and improve moisture retention. In containers, use premium quality potting soil.

Water requirements: Keep soil consistently moist through the growing season. Add a mulch layer to slow water evaporation from soil. In containers, water whenever the top inch of soil is dry.

Frost-fighting plan: Basil is very frost-tender and damaged by temperatures below 40º F. Use a frost blanket to protect newly planted seedlings from late spring frosts or prolong the fall growing season.

Common issues: Pinch flower buds to keep plants from bolting. Once flowers form, leaf flavor changes. Pests to watch out for: aphids, slugs, Japanese beetles, and earwigs. Fungal diseases sometimes occur in humid climates, and root rot is common in poorly drained soil.

Growing tips: Pinch or prune basil plants as they grow to promote branching and bushiness. Never cut into the woody parts of a stem; plants won’t resprout.

Harvesting: Pick leaves at any point in the growing season. Choose individual leaves, or snip leafy stems to the length you desire.

Storage: Cut basil stems and place in water like a fresh bouquet. They’ll last for weeks, provided you remove any leaves below the water line and change water regularly. Never place basil in the refrigerator; the cold air damages leaves. Preserve basil by freezing or in herbal vinegars.

For more information, visit the Basil page in our How to Grow section.

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PHOTO: Stephen Melkiesthian/Flickrby Patricia Lehnhardt April 22, 2019

Choosing from the array of basil varieties to plant might be the most difficult part of growing this herb. It has minimal growing requirements—full sun (at least six hours a day), warm temperatures (above 50 degrees F) night and day and fertile soil with adequate moisture—but there are more than 40 known varieties (as well as many ways to market it to sell). Your local garden center probably offers a few varieties as seedlings, but to grow the most unusual basils, you’ll need to start from seed.

To help narrow your selection, determine how you will use it: to color in the landscape, as an ingredient in food or drinks, as a garnish, or to make a year’s supply of pesto (or any of our five creative uses). Below is a list of 10 varieties and their uses to help you make your decision.

1. Christmas Basil

With 2-inch, glossy green leaves and purple flowers, Christmas basil adds fruity flavor to salads and drinks, and the plants are gorgeous in the landscape. A beautiful border plant, it averages 16 to 20 inches tall.

2. Cinnamon Basil

This variety has a delightful fragrance and spicy flavor. A beautiful, 25- to 30-inch-tall plant with dark-purple stems and flowers accented with small, glossy leaves, it’s my favorite basil to use for fresh arrangements and in fruit salads and garnishes.

3. Dark Opal Basil

A must in my garden, Dark Opal basil adds color to fresh summer floral displays and depth to dried arrangements and wreaths. Beautiful and spicy in a salad or garnish, it can also be made into pesto, which adds an unexpected color and flavor to your pasta or bruschetta. The plants are attractive in the herb garden, ranging from 14 to 20 inches in height with purple stems, flower and leaves.

4. Holy Basil

A revered plant in the Hindu religion, Holy basil is also referred to as Sacred basil or Tulsi. Its leaves can be used to make tea for boosting your immune system. It is a beautiful plant in the garden with mottled green and purple leaves and grows to about 12 to 14 inches tall.

5. Lemon Basil

This variety can be added to salads and fish dishes with abandon. A sprig of Lemon basil in a glass of iced tea is particularly delightful on a hot summer day. The 20- to 24-inch plants are light green with white flowers and 2½-inch-long leaves.

6. Lime Basil

With small green leaves on compact, 12- to 16-inch plants with white flowers, this variety’s lime scent and flavor makes it great in fish and chicken dishes. A simple syrup infused with Lime basil is a delicious addition to tea and margaritas.

7. Spicy Bush Basil

The cutie of the basil garden, Spicy Bush basil has tiny leaves on small, mounded plants, which are perfect for pots or lining the garden in bonsai-like fashion. It only takes a few of this variety’s intensely flavored leaves to add a punch to a sauce or soup. The plants are a soft green and about 8 to 10 inches in height and width, with 1/2- to 1-inch-long leaves.

8. Purple Ruffles Basil

A feathery variation of Dark Opal, Purple Ruffles adds another dimension to the landscape, floral arrangements or garnishes. It has the same flavor as Opal and can be used similarly. It is a 16- to 20-inch-tall plant with 2- to 3-inch-long leaves.

9. Sweet Basil

This basil cultivar is the best choice for Italian sauces and soups and for making pesto. Varieties include Genovese, Napoletano, Italian Large Leaf and Lettuce Leaf. Plants range from 14 to 30 inches tall and are prolific in hot, sunny locations. Harvest the top four leaves often to keep the plant growing and sweetly flavored.

10. Sweet Thai Basil

An Asian variety with a distinct, spicy, anise-clove flavor, quite unlike common sweet basil, sweet Thai is a must-have addition to Asian cuisine and makes a nice addition to the herb garden for fragrance and color. It has purple stems and blooms with green leaves reaching 12 to 16 inches tall.

Thai Basil: Uses, flavor profile and how to grow indoors

A cousin of the commonly grown sweet basil, Thai basil (Ocimum basilicum) is becoming a popular herb grown in home gardens as culinary tastes expand. Like so many other herb specimens it is easy to grow inside as long as its basic sunlight and temperature requirements are met. Read on for uses, a comparison to other basil types, and step by step indoor growing instructions for Thai basil.

Uses for Thai basil

Similar to other basil varieties, Thai basil is typically grown for culinary uses, but it also has some medicinal properties. Its striking physical appearance also lends it to be a beautiful ornamental piece.

Culinary uses: Thai basil is used in cuisine originating from Thailand, Vietnam, Laos, and Cambodia. Most recipes call for fresh Thai basil but dried or frozen can be substituted if necessary.

Medicinal uses: Leaves can be bruised and the aroma inhaled, or the bruised leaves can be rubbed across the forehead and beneath the eyes to promote relaxation.

Differences between Thai basil and other types

Basil is available in over 40 different cultivars with varying characteristics. Some of the favorited types grown are sweet basil, lemon basil, Genovese basil (a variety of sweet basil), holy basil, Thai basil, and opal basil.

Thai basil is known for its differing flavor, appearance, and ability to hold up better in culinary uses.

Thai basil has a stronger flavor profile and aroma than the more commonly grown, sweet basil. Its flavor is described to be anise or licorice-like and is spicier in nature. Sweet basil has larger, brighter green, shiny leaves – the hallmark of Italian cuisines and pestos.

Plants have small, narrow leaves, dark purple stems, and pink flowers. The leaves smell like anise; essential oils present in leaf tissues have the highest odor intensity of the basil types (1). The most popular cultivars found in stores and markets have dark green leaves and white flowers; plants have a rich, spicy, pungent aroma.

It also holds up better under higher temperatures and prolonged cooking times than sweet basil.

Thai Basil in bloom. Image: drewwest75

How to grow indoors

Native to the tropical regions of southeast Asia, Thai basil prefers full sun, warm conditions similar to the sweet basil commonly grown in gardens and kitchen windowsills.

Thai basil plants grow well outside when they can take advantage of the hot summertime temperatures and long days. Grow naturally declines as temperatures drop in the fall and day lengths start to shorten; in most growing zones grow will halt completely in the winter.

In order to grow Thai basil plants indoors, it’s important to mimic the outdoor conditions of summertime. Provide plants with plenty of sunlight – supplementing with grow lights if necessary – and keep them in a warm location to encourage strong, healthy growth of plants and the best tasting foliage.

Light Requirements

Adequate sunlight is needed to drive photosynthesis – the process of converting carbon dioxide and water into sugar plants use for food (2).

When growing Thai basil indoors, plants require a minimum of 6 hours of sunlight a day. Position plants in a south or west-facing window if possible.

South facing windows provide the most sunlight exposure in homes, with light streaming through them all day. Windows facing westwardly receive a long period of direct sunlight but often miss the hottest, most intense part of the day making them a great alternative.

If your home doesn’t have enough direct light from the sun for your basil plants, purchase a simple growing light to supplement natural sunlight.

Temperature Needs

Basil plants are very sensitive to cold temperatures. They thrive in conditions between 72-85°F. During winter months keep them away from drafty windows or frequently opened doors that let in cold air. Even a short dip down to 50°F will impede growth for a length of time afterward.

Supplies needed for growing indoors

With a few basic supplies, it’s easy to start growing Thai basil plants. Supplies are similar for growing most other herbs, sweet basil included.

Containers: Choose from either clay (either glazed or unglazed) or plastic pots based upon your personal preference and decorating style. A 6-inch pot is sufficient for a single plant; 3 plants can be grown together in a 12-inch container.

Growing Media: Commercial potting mixes and coconut coir both make an excellent substrate for growing plants. Both media are lightweight with excellent moisture retention. Fox Farm is one of our go-to potting soils, we find that it works especially great in container growing. You can purchase it at Amazon.com here.

Plants: Thai basil can be started from seeds or propagated through plant cuttings.

Supplemental lighting: Plants need a high amount of sunlight when grown indoors for maximum growth and yield. Often times indoor spaces cannot provide the full-sun conditions similar to growing outside; in this case, plants should be supplemented with light via grow lights. Thai basil responds well to either fluorescent or high-intensity discharge (HID) growing lights. Check out our favorite light on Amazon.

Photo taken by F Delventhal at Clagett Farm CSA.

Planting Instructions

The instructions for planting Thai basil varies slightly depending on the method and the desired end result. As mentioned previously full-sized plants can be grown via seed or stem cuttings.

Starting Thai basil from seeds:

  1. Fill container(s) with pre-moistened potting soil.
  2. Sprinkle a small number of Thai basil seeds across the top of the mix and cover lightly.
  3. Place container(s) in an area where the ambient temperature is at least 70℉.
  4. Keep the soil moist but not saturated.
  5. Thin plants after true leaves emerge when they reach a couple of inches tall. Keep the single, best-looking plant for a 6-inch container, the three best-looking seedlings for a 12-inch container.

Starting Thai basil from stem cuttings:

  1. Take a 4-inch stem cutting right below a node and remove all of the leaves from the bottom 2 inches of the stem.
  2. Place the cut end of the stem in a glass or jar of water, allowing it to grow until newly generated roots are a couple of inches long.
  3. Fill the container(s) with pre-moistened growing media of your choice, carefully planting the rooted cuttings.

Caring for your Thai basil plants

Thai basil plants are fairly low maintenance when grown indoors.

  • Water containers when the potting soil is dry to the touch. Thai basil is native to tropical regions but prefers a well drained potting mix.
  • Avoid getting water on the foliage when watering the plants. Water the soil directly if possible.
  • Fertilize plants every 4-6 weeks using a water-soluble fertilizer at half strength.

Harvesting

Thai basil plants respond well to frequent harvesting; regularly removing foliage from your plants will trigger new growth, encouraging full, bushy plants.

  • Harvest mid-morning on a sunny day when essential oils are at their peak.
  • Using clean, sharp scissors or even your fingernails, snip or cut off stems right above the node where a pair of leaves originates.
  • Periodically pinch off branch tips to encourage your plant to grow outward instead of upward for a fuller shape.
  • If plants are overgrown, you can do a more severe harvest. Starting from the top of the plant begin harvesting stems, taking the plant down to 6 inches tall. Never cut into the woody parts of the stem; the plant won’t resprout.
  • For the best flavor, harvest basil leaves before plants flower. If they do flower, remove flowers and wait to harvest for a couple of days.

Storage Methods

After harvesting you can opt to use your fresh Thai basil, or you can preserve it by drying it, freezing it, or preserving it in oil.

Drying

To dry it in a food dehydrator, place washed leaves in a single layer on the food dehydrator trays. Dry at the recommended temperature until leaves are crispy.

To air dry, bind a clump of 6-inch long stems together to create a bunch. Punch some holes in a small paper bag and place the bunch inside the bag; the bag will catch any leaves that fall off. Hang the bag in a dimly lit or dark room where the temperature is warm and the humidity low.

To learn more about the different drying methods check out our how to dry herbs guide.

Freezing

To freeze Thai basil, remove whole leaves from the stems, and blanch for two seconds, immediately placing leaves in an ice bath afterward. Dry completely and store in an air-tight container or freezer bag, separating layers with wax paper.

Preserving

To preserve in oil, place blanched basil leaves in a blender or food processor, adding 1 to 2 cups of olive oil and a ½ teaspoon of kosher salt for each cup of basil. Pulse until blended. Then strain the mixture or leave it as it is for a stronger flavor. Use immediately, refrigerate in a glass container for up to a week, or freeze in ice cube trays.

Conclusion

Growing Thai basil in your indoor herb garden adds a variety of flavor to your Asian culinary adventures while contributing to the overall aesthetics of your decor with its beauty. Plants are low maintenance, preferring full sun locations and warm temperatures. When these conditions are provided you will be rewarded with lush, aromatic foliage for harvesting and use.

Thai Basil Plants: Tips For Growing Thai Basil Herbs

With their lovely purple stems and purple-veined leaves on a shiny, dark green background, Thai basil plants are grown not only for their culinary uses but also as an ornamental specimen. Keep reading for more information on Thai basil uses.

About Thai Basil Plants

Thai basil (Ocimum basilicum var. thyrsiflora) is a member of the mint family and as such has a particular sweet flavor reminiscent of anise, licorice and clove. Popular among the cuisines of Thailand, Vietnam, Laos and Cambodia, growing Thai basil has a pleasing aroma similar to sweet basil and is generally used fresh in recipes.

Also referred to as ‘Sweet Thai,’ Thai basil plants grow to a height of between 12 to 18 inches with leaves 1 to 2 inches long on purple stems with purple flowers. Like sweet basil, Thai basil is a perennial.

How to Plant Thai Basil

If we look at how to plant Thai basil in the home garden, our first concern is obtaining the plants. Thai basil can be purchased from the nursery or started from seed. If the choice is to purchase from the nursery, pick up a rosemary plant as well. Rosemary and Thai basil work well planted together as they enjoy similar well-drained soil, water, and fertilization.

Handle the plants carefully, as they are quite delicate. Plant the new basil in a sunny area, water in and fertilize with a nutrient rich fish emulsion or seaweed solution two to three times during their active growing season.

Sun is a key ingredient. Thai basil plants need at least six hours of direct sunlight to flourish.

Water weekly but keep the water off the leaves; water from the base. Over-watering will cause the leaves to yellow and drop and under-watering will make flowers and buds suffer, so it is important to attain a balance when watering Thai basil.

Harvesting Thai Basil

When harvesting Thai basil, remember to be gentle as the leaves bruise easily and you don’t want that to happen until you are going to use them. Harvest the leaves in the morning when their essential oils are at their peak and the flavor of the growing Thai basil will be at a premium. Also, water the Thai basil prior to harvest to intensify the flavor.

Growing Thai basil tends to be more compact than other types of basil, so harvest at the top of a group of leaves; otherwise, the stem will rot. If you make a mistake, cut the stem all the way back to the next set of leaves. Unless, you are growing Thai basil as an ornamental, cut the flower off several days before harvest so the plant can focus all its energy on the leaves. When you harvest your growing Thai basil plant, take it down to about 6 inches.

Thai Basil Uses

Now that you have harvested the basil, what are you going to do with it? Some Thai basil uses are to infuse with vinegar or oil, to flavor Pho with mint and chilies, make tea, or pair with most any chicken, pork or beef dish. Recipes online include one for making Thai basil beer and a recipe for Thai basil pesto with peanuts, rice vinegar, fish sauce and sesame oil, which will keep in the refrigerator for a week. Yum!

Thai basil is usually used fresh, preferably soon after harvesting, but you can also chop it up or run it through a food processor and freeze in ice cube trays. Once frozen, remove from the tray and store in resealable bags in the freezer for up to two months.

Thai basil may also be used as an aromatherapy treatment by bruising the leaves and inhaling their aroma. They can also be bruised and rubbed beneath the eyes and on the forehead for a relaxing reprieve from a long stressful day.

Thai basil’s sturdy leaves and spicy anise flavor make it the perfect companion to food from all over Asia.

One cultivar especially worth seeking out is Thai basil,* which is now grown domestically and is increasingly common in Western markets and specialty Asian groceries. If all you’ve ever known is Italian sweet basil, you’ll may be surprised by its crisp pungency that plays particularly well with Southeast Asian food. It adds a fresh, herbal-licorice flavor not quite like anything else.

* Which is different from holy basil, a more medicinal-tasting herb also used in Thai cooking.

With purple stems whose color intensifies as the plant grows larger, Thai basil’s leaves are sturdier than floppy sweet basil, and its slim, pointed shape more closely resembles mint than its Italian cousin. Its flavor is markedly different than Italian sweet’s: when tasted alone, its unmistakable liquorice-y notes are most salient; overall, Thai basil is bolder and slightly spicier than the sweet kind.

Thai basil brings pungency to Taiwanese three cup chicken.

It’s a versatile herb, though, and good to have on hand for a punchier caprese or ratatouille, but its true boon is the anise intensity it brings to East and Southeast Asian dishes from Thai coconut milk curry to Taiwanese three cup chicken. Tried these dishes at home but felt they lacked a certain fresh pungency? Thai basil can solve that problem.

If you live in a city with a Southeast Asian population, you can likely find Thai basil in specialty groceries catering to those communities; additionally, some farmers are beginning to grow and sell the herb at local farmers markets. (You can also order them online.) Like Italian sweet basil, fresh Thai basil leaves should have a bright color and a not-droopy demeanor, and they don’t take too well to drying, so take the time to seek out fresh versions.

It’s great with green curry, too.

Thai basil is wonderful eaten raw, slivered, and added to salads, both your plain old cucumber-tomato salad or something meaty like northern Thai larb. But its hardy leaves stand up especially well to cooking—their flavor infuses readily into food and the leaves don’t wilt quite as much as Italian sweet basil’s would. Try Thai basil in simmered dishes like Taiwanese braised eggplant and green curry as well as high-heat stir-fries such as Thai basil chicken and Thai tofu (traditionally made with holy basil, but great with Thai basil, too).

Looking for more ways to use your Thai basil? Some more recipes right this way:

  • Cellophane Noodles with Pork and Thai Basil
  • Dave Arnold’s Thai Basil Daiquiri
  • Thai Beef Rolls with Sweet Chili Sauce
  • Spicy Noodle Bowl with Beef and Mango
  • Taiwanese Three Cup Chicken

All products linked here have been independently selected by our editors. We may earn a commission on purchases, as described in our affiliate policy.

How is a Thai basil different from a regular basil?

I grew three different varieties of basil plants in my kitchen garden last year.

Sweet basil, also known as regular or Italian basil (botanical name: Ocimum basilicum) is a fragrant herb used extensively in Italian cooking. Sweet basil has bigger leaves than those of Thai basil. As per the name, sweet basil has a sweet aroma and its flavor is also mild. Sweet basil has round leaves and gets white flowers.

Thai basil (botanical name: Ocimum thyrsiflora) has a stronger aroma and flavor than that of sweet basil. Thai basil leaves are pointed, dark green in color and the plant gets pink-purple flowers.

Thai basil has a purple stem which is different than that of sweet basil.

Along with sweet basil and Thai basil, I also grew Tulsi, also known as holy basil (botanical name: Ocimum sanctum). Also known as the Indian basil, holy basil is considered an ancient herb which is thousands of year old! We find frequent mentions of Tulsi in Ayurvedic texts and the herb has medicinal properties. Holy basil has small leaves and is pungent in taste. Below is a picture of Tulsi.

All three basil plants belong to the same family Lamiaceae- similar to mint, sage, rosemary, oregano, and lavender. All the culinary flowering herbs of the Lamiaceae family are aromatic.

(photo source)

Footnotes

Kitchen Garden | Vegetable Garden

Thai Basil – Bai Horapa

by Kasma Loha-unchit

See also Kasma’s information on Holy Basil (Bai Gkaprow).

Thai Sweet Basil, or Anise/Licorice Basil (Bai Horapa): This tropical variety of sweet basil provides the unusual basil flavor present in so many Thai dishes that it has come to be identified as “Thai basil” in America, even though the Vietnamese and Laotians also use lots of it in their cuisines. Its leaves are deep green, smaller and not as round as Western sweet basil. They grow on purplish stems, topped with pretty, reddish purple flower buds. Both leaves and edible flowers are sweetly perfumed with a mix of a distinctly basil scent and that of anise or licorice. Therefore, it is, therefore, sometimes referred to as “anise basil” or “licorice basil,” though it is not the same as the Western strain of these basils stocked by local plant nurseries.

Plentiful in Thailand, bai horapa is eaten almost as a vegetable. It is used in large quantities, in whole leaves and sprigs, in many types of dishes, including curries, stir-fried dishes, salads and soups. I am reminded of the wonderful clam dish my mother frequently made during my youth, a favorite of the family. Big handfuls of this basil were tossed in the hot wok with the very sweet, succulent and tasty thin-shelled hoi lai (“clams with a patterned shell”), garlic, roasted chilli paste (nahm prik pow) and fish sauce – delicious! See Clams Stir-fried with Roasted Chilli Sauce and Basil (Hoi Pad Nahm Prik Pow).

Bai horapa is now readily available year-round wherever there is a sizable Southeast Asian population to support a market of its own. As demand for this great-tasting basil increases, specialty produce markets and gourmet grocery stores are beginning to add it to their herb selections. It is also easy to grow, and seed packets can be purchased from local nurseries, ordered from national seed catalogues or ordered online. You can root a fresh stem easily by placing it in a glass of water outside the refrigerator. As with many leafy herbs, this basil can be kept fresh by placing it in a glass with the cut ends in water, covering it with a plastic bag and storing it in the refrigerator. Or, you can wrap the herbs in paper towels before bagging them in plastic for refrigerating. They will stay fresh for about a week.

Our Ingredients Index contains links to many more Thai ingredients.

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