Basil is sometimes referred to as “the king of herbs”.
And no wonder. Basil is easy to care for and will quickly grow into big, bushy plants that abound in delightfully scented foliage.
Having been cultivated for more than 5000 years, basil’s long history alongside humans makes it one of the most popular and enduring herbs. For many, it’s an indispensable member of the herbal garden.
Basil is a tender herbaceous plant in the mint family, native to tropical areas of the Old World from central Africa to Southeast Asia.
The most familiar, useful, and widely grown basil is sweet basil (Ocimum basilicum).
A true culinary darling, sweet basil grows about two feet tall from a central stalk. It bears large, medium green, 3-inch long, opposite oval leaves that have a robust clove-anise flavor.
By midsummer, a single spike clustered with small white flowers will arise above the leafy foliage. Though basil blooms are quite lovely (and are absolutely adored by bees and other pollinators), these are usually removed to prolong the harvest.
Sweet basil readily cross-pollinates and polymorphs with other members of the Ocimum genus. This has resulted in more than 60 subspecies and hybrids of Ocimum basilicum with varying color, flavor, and forms.
Cinnamon basil, dark opal basil, lettuce leaf basil, lemon basil, Thai basil, and globe basil are some of the other sweet basil varieties to explore.
Basil isn’t only a culinary herb and there are plenty of ornamental basils that grown more so for their looks.
Bush basil (O. minimum), holy basil (O. tenuiflorum), and African blue basil (O. kilimandscharicum) are fragrant and pretty annuals worth adding to the flower bed.
Basil Growing Conditions:
No matter the variety, all types of basil thrive in warm weather and long days filled with sunshine.
As a native to the tropics, basil is hardy in USDA zones 10 to 11. In other areas, it is grown as an annual.
Plant basil in a location that receives 6 to 8 hours of sunlight each day.
Basil performs best in loose, well-draining soil enriched with organic matter, like compost.
Give basil about an inch of water per week. This plant dislikes wet feet so try to water basil in the morning so the soil can dry out a little before nightfall.
If you added compost to your soil, you shouldn’t need to fertilize basil throughout the summer. But if basil leaves are small or the whole plant looks stunted, work some more compost into the soil.
Basil is a great neighbor for tomatoes, peppers, asparagus, and oregano. Its aromatic leaves help deter pests, its flowers attract pollinators, and it can help improve the flavor and growth rate of nearby crops.
How to Grow Basil
From seed to harvest, basil loves the heat and abhors the cold. Be patient and wait until temperatures are just right before putting basil plants outdoors.
Basil seeds can be sown directly into the garden so long as the soil has warmed to a bare minimum of 50°F (10°C).
You can also start your basil seeds indoors to get a jump on the season. Basil seeds germinate readily and can be started 6 weeks before the last frost date in spring:
- Sow a few seeds to a pot or scatter in flats a ½-inch deep with your favorite seed starting mix.
- Water gently and cover with a humidity tent.
- Place pots in a warm spot with ambient temperatures between 60°F to 80°F (15.5°C to 27°C). Basil seeds will germinate in about 5 days if kept around 70°F (21°C).
- When sprouts have emerged from the soil, remove the cover and move plants to a sunny windowsill.
- Thin seedlings to 6 to 8 inches apart.
- Keep the soil consistently moist but not too wet.
- Once basil seedlings are 6 to 8 weeks old, and all danger of frost has passed, basil can be hardened off and transplanted outdoors.
- Basil will grow best if soil temperatures are around 70°F (21°C). Wait to plant basil outdoors if nighttime temperatures still drop below 50°F (10°C).
Basil is super easy to propagate by cutting if you already have a healthy, established plant that hasn’t yet flowered:
- Take 4-inch long stem cuttings, snipping them off just below a leaf node.
- Remove the leaves from the bottom 2-inches of each cutting.
- Pop cuttings in a cup of water and place in a sunny location.
- Top up the water as needed and completely change out the water every week.
- You should see signs of root growth in less than a week.
- When roots are about 2-inches long, cuttings can be planted in potting soil.
- Wait for temperatures to rise before hardening off and transplanting outdoors.
Read Next: 15 Herbs You Can Propagate From Cuttings
From Starter Plant:
Most everyone loves basil and it’s easy to find starter plants for sale – even at the supermarket – come spring.
When purchasing basil plants, look for young, compact seedlings with healthy green leaves. Avoid buying tall and leggy plants, or any that have brown spotting on the foliage.
- Once soil temperatures have sufficiently warmed, prep the planting site by amending the soil with a 2-inch layer of compost.
- Dig a hole roughly the same size as the pot and gently remove the seedlings from the container.
- Plant basil at the same depth as the container it was growing in.
- Plant seedlings at least 8 inches apart. For larger, bushier plants space them 12 to 18 inches apart.
- Soon after transplanting, give your basil plants a good drink of water.
How to Harvest Basil – The Secret To Big, Bushy Plants
Basil is ready for its first round of harvests about 60 days after setting the seeds into the soil. Allow your plants to reach at least 6 to 8 inches in height before you begin to take cuttings.
With some leafy greens, you can simply pick off any tasty looking leaf at random. But this would be precisely the wrong way to prune and harvest your basil plants. Plucking off individual leaves in this fashion will turn full and bushy plants into leggy and scraggly things with far less leafy growth.
The correct way to prune basil is to take cuttings from the upper portion of the main stem. Follow the stem down and find a spot where a Y-axis is formed by two leafing branches. There should be tiny new growth sprouting from the nooks of each branch. Cut just above this leaf node.
Basil responds very well to this treatment. Those little budding leaves will eventually branch out and become two new stems that can be snipped in the same manner. Two stems, then four, eight, sixteen – on and on until the first frost.
Because basil will keep branching out after each harvest, plants will maintain their vigor and bushiness throughout the entire summer.
That’s why correct pruning is the key to growing a huge basil plant. We’ve dedicated an entire article to the process of correctly pruning basil – have a read of it here.
In the article you’ll also see how this technique (plus a few more tricks) were used to grow this huge basil plant from a supermarket starter plant.
Starting in June, basil plants will put out flowers all the way until the first frost. With the exception of ornamental varieties, you’ll want to pinch out the flowering spikes as soon as soon as you see them to keep the plant from going to seed. Basil foliage will be at its most intensely flavored when blooms are promptly removed.
Uses for Basil
Harvest basil regularly and you will have yourself a tidy sum of leaves. Six basil plants will easily yield about 2 to 3 cups of leafy greens each week!
If you don’t know what to do with all that basil, here are 15 ways to use it that go beyond making pesto.
How to Store Basil
As with so many goodies from the garden, basil is best when it’s fresh.
If you can’t use it right away, place your basil cuttings in a cup of water in a sunny windowsill. This will help extend the freshness window for a few more days.
For the longer haul, freezing basil is the next best thing for maintaining good flavor for several months. Take a look at our article here as Rural Sprout editor, Tracey, tests out four techniques for freezing basil and reveals the simplest way.
Hanging and drying bundles of basil is another option, though dried basil will lose some of its flavor.
Basil Seed Saving
To collect seeds for next year’s grow, let one or two of your basil plants finish flowering.
Harvest flower spikes when they are brown and brittle.
Place them in a paper bag or small plastic tub. Crush up the flowers with your hands to release the seed pods.
Use a fine mesh sieve to separate the seeds from the chaff. Basil seeds are tiny and black and will slip right through the screen. Be sure to hold the sieve over a container so no seeds go to waste.
Keep sifting to remove most of the tiny bits of plant debris.
Store basil seeds in a cool, dark place and they will remain viable for about 3 years.
It’s important to note that when growing more than one variety of basil in the season, the seeds you collect won’t be true-to-type. That’s okay though, you could chance upon some really interesting crosses – a lemony basil plant with purplish leaves for example!
To keep basil plants true, though, only grow one type per season. If you must grow more varieties, keep them at least 150 feet apart to avoid cross pollination.
Unless you reside in a frost-free region, your good times with basil will be over after the first cold snap.
But it doesn’t have to end this way. Take a few cuttings from your best performing basil plants, root them in water, and pot them up.
Basil is so easygoing that it’s a great candidate for kitchen herb gardens. Just give indoor basil plants plenty of warmth and bright light and they will happily provide more leafy greens.
In spring, root some more cuttings from your indoor basil plants to get a head start on the outdoor growing season.
The most common insect pests for basil are aphids, Japanese beetles, and slugs.
Prevent aphid infestations in the first place by planting cultivars that attract beneficial insects to your yard. Hover flies, wasps, and ladybugs are some of the best biological pest controls around.
Otherwise, hose down your basil plants with a strong stream of water to knock aphids off. Apply a soapy spray to repel any future incursions.
Japanese beetles can be hand-picked off plants and dropped into a cup of soapy water. Same goes for slugs.
Basil may also be attacked by several diseases when grown in less than ideal conditions.
Powdery mildew, downy mildew, root rot, leaf spot, and gray mold are some of the fungal diseases basil is susceptible to. Much of them can be prevented by ensuring your plants have good air circulation and proper drainage. When watering your basil plants, always water at the base of plants and avoid wetting the leaves.