How to Grow and Care for Holy Basil

Krishna Tulsi or Holy basil plant in bloom.

Suprabhat Dutta/ Getty Images

Holy basil doesn’t make your pesto divine. It isn’t even the same species of basil used in your favorite Italian dishes at all.  Holy Basil or Tulsi can be two different herbs, Ocimum gratissimum, or Ocimum tenuiflorum.  The wonder herb holy basil often called “The Queen of Herbs,” is native to Africa or Asia and is commonly used in Ayurveda (traditional medicine in India) to make healing teas, oils, and poultices.

Easily propagated by seed or a cutting, holy basil is grown as annual in most of the United States, but will grow as perennial in warmer climates and can even do well as an indoor plant in the right conditions. Even those who have no interest in its medicinal and culinary uses plant the lovely herb for its attractive foliage and flower and alluring aroma.

Whether growing holy basil for medicinal, spiritual, culinary, or aesthetic purposes, the herb will be a beautiful and satisfying addition to your garden or as a houseplant collection.  

Botanical Name Ocimum tenuiflorum, Ocimum gratissimum
Common Name Holy Basil, Tulsi
Plant Type  Herbaceous Shrub
Mature Size 1-2ft Tall- 1-2 Feet Wide
Sun Exposure Full Sun
Soil Type Moist, sandy loams with good drainage
Soil pH Adaptable.
Bloom Time Seasonal
Flower Color Purple-White
Hardiness Zones 5-9, USDA
Native Area  Indian Sub-Continent, Africa
Toxicity Non-toxic

Holy Basil Care

Growing holy basil is an easy endeavor, regardless if you plan to grow it from some seed, cuttings, or starters. The most challenging thing you will encounter may be finding plants, so propagating from seed is usually the best bet. If you do happen to find some holy basil, be sure you have the correct species. When selecting plants, knowing the difference between Thai basil (O. basilicum  var. thyrsiflora) and holy basil, sometimes called Thai holy basil, will decide whether you make a healing tea or one that tastes like pesto.  

Holy Basil can grow directly in your garden or a container both indoors, as a houseplant, or out and be brought in to overwinter. Either way, the methods of caring for both are similar.

Light

Giving holy basil plenty of sunlight will ensure you have a good amount of large healthy leaves. It will take some shade, but anything more than dappled shade, you will notice some decline in the plant’s welfare.

Soil

Though holy basil does grow quite well in most soils, ensuring it thrives takes minimal effort at all. The ideal soil type is light and airy but rich at the same time. A silty loam is a good choice for a soil type that can retain some moisture but drains well. Soaking wet soil is not the outcome you are going for with your growing medium; if this is an issue, you can always amend it with perlite.

If you plan to plant your holy basil in a container or raised bed, the best soil mix to use would be three parts peat moss, one part compost or manure, one part perlite.

Water

Keeping your soil moist but not drenched and soggy is the key to growing healthy and abundant holy basil. This rule applies whether you are growing the plant indoors or out. 

Another consideration when watering basil is a disease, Basil Leaf Spot, that is often spread by infected soil being splashed up on the plant. Soaker hoses or misting nozzles work wonders to alleviate this issue.

Temperature and Humidity

Holy basil’s native range is located in a tropical region, so maintaining an average temperature of 70 degrees Fahrenheit is necessary if you want the plant to survive outdoors. If your temperature is above this year-round holy basil will act as a perennial. In cooler hardiness zones, the plant will be annual unless you plant it in a container. The USDA recommends holy basil will do well in USDA zones 5-9, but you can grow it indoors in any zone.

Fertilizer

Fertilizing any herbs is not a great idea. The best method of providing nutrients is ensuring the plant is given a lot of good quality soil and maybe enriching that soil with some compost. If an herb is given fertilizer, what happens is that the foliage grows larger and quicker than necessary, and
you induce profuse rapid flowering. Usually, these would be welcome on plants but what occurs is that the essential oils in the herbs are not as concentrated in the leaves, and you end up having very weak flavorless herbs. Inducing early flowering means energy is spent on blooms and not on leaves, and again, the leaves are, for the most part, where the magic happens. So it's best to skip the fertilizer.

Is Holy Basil Toxic?


Holy basil isn’t toxic. It has been used for millennia in traditional medicine and various Asian culinary traditions. The herb’s leaves make an incredibly delicious tea known to invigorate and refresh in place of a caffeine substitute.

Holy Basil Varieties

  • Rama tulsi has a cool flavor known for its mellowing effects. Rama has green foliage, purple blossoms, and a green or purple stem, depending on the season.
  • Krishna tulsi tastes similar to black pepper and is known for its high medicinal value. Krishna holy basil is dark green with violet stems, foliage, and light purple blossoms. It grows in the meadows of the Indian Sub-Continent and has been successfully cultivated for private gardens and use in temples.
  • Kapoor tulsi the most widely cultivated variety you will find in the United States. It is a short-growing annual variety that bolts quickly with profuse flowers and a mild flavor compared to other varieties. Due to the number of flowers, this variety is an excellent food source for pollinators but the least attractive for medicinal uses. If planning to bring your plant indoors, seek out one of the other varieties.
  • Amrita tulsi is the least commonly grown, and least discussed. Amarita tulsi means immortality, and that is fitting for this plant. It is a perennial that is nearly indestructible and simple to grow. If you plan to grow holy basil in a container, this is the variety to select. 
  • Vana tulsi called holy basil and tulsi but it is actually the species O. gratissimum. The variety is incredibly aromatic compared to the others. Vana has green leaves and stems with white blossoms. It is used mostly medicinally.

Propagating Holy Basil

If planning to start your holy basil using seed, you will want to do this indoors four to six weeks before the first frost in a good seed starting mix. Using a heat mat will increase the speed and germination rate. Placing a fan to blow cool air over the seedlings will produce stronger plants.

Propagating from cuttings is an easy task. You will use a pair of sharp sanitized snips or a sharp grafting knife and make an angled cut about six inches long just below a leaf node. Remove the lower leaves from the cutting and place the cutting in water, changing the water frequently. Wait till roots develop and then transplant.