How to Prune Basil

Basil is a reliable, aromatic culinary herb. A popular part of the herb garden the plants typically grow from a single stem. A tender annual, the fragrant leaves are commonly used with tomatoes. You can also use the leaves to add flavor to drinks.

If you are growing basil you will be aiming to cultivate a plant with as many leaves as possible. Learning how to prune basil correctly helps to make this possible. This guide is designed to take you through the entire process, helping you to cultivate a bushy and productive plant.

Regular pruning encourages a healthy, bushy specimen to develop. 

Why Should I Learn How to Prune Basil?

Knowing how to prune basil correctly is key to successfully cultivating a healthy, bushy plant.

In the course of this article we will reveal how to prune basil so that the plants continue to grow, becoming large and bushy. The advice outlined in this article can be applied whether you are growing from seed or cultivating a plant purchased in a garden store.

Regularly pruning these plants helps to prevent them from becoming scraggly, sparse, tall or leggy. It also prevents too much woody growth from developing. Instead, correctly pruning the plants encourages them to grow large and healthy.

Learning how to prune basil correctly helps to encourage the plant to develop lots of leaves and stems. Regular pruning also means that you can shape Sweet cultivars, the most commonly grown type, into a rounded bush which is 18 to 24 inches tall.

The advice outlined below can also be applied to other commonly grown varieties including Thai, Lemon and Genovese.

Learning how to prune basil is more than just removing the leaves.

Regularly pruning plants encourages them to develop a vigorous, productive growth habit. Finally, learning how to prune basil correctly also helps to keep the plants healthy.

How to Grow Basil

Before learning how to prune basil, you need to know how to cultivate a healthy plant.

The plants are pleasingly easy to grow from seed. All the seeds need to germinate is warm soil.

Following germination the plants grow best in temperatures of 80 ℉ and over. If the temperature consistently falls below 45 ℉ the plants struggle to grow and survive. These are tender herbs and do not tolerate frost.

Growing undercover, either in a greenhouse or on a kitchen windowsill helps to promote growth in cooler climates.

In northern, cooler climates the plant has a relatively short growing season. In contrast, growers in southern climates will enjoy a longer growing season. However, exposure to consistently warm temperatures does encourage flowers to set.

The flowers of the plant are both edible and attract scores of pollinators. If you are allowing the plants to go to flower, placing them close to fruit and vegetable plants can help to increase yield.

This reliable herb is a good companion plant for a range of different vegetables and flowers. Some of the most commonly grown combinations include:

• Tomatoes,
• Bell Peppers.
• Marigolds,
• Asparagus,
• Nasturtium,
• Potatoes,
• Cilantro,
• Chives,
• Parsley.

Many people try to deter the plants from flowerings. Allowing the plants to flower can turn the leaves bitter. Flowering also causes a terminal bud to form. This halts the growth of new leaves. If you want to stop your plants from setting flower, you will need to prune them. I will explain how to prune basil to prevent flowering later in the article.

The plants are best placed in a sunny spot with some partial shade. Growers in warm or tropical ones, USDA Zones 9 and higher, should ensure the plants receive lots of afternoon shade. This helps to prevent the leaves from scorching or becoming sunburnt.

Basil grows just as well in pots as in garden beds. Small pots, 6 to 8 inches in size are ideal for most situations. In tropical climates, where the plants can grow larger, you may need a bigger container.

The plants grow happily in small pots. 

Plant in well draining soil that retains some moisture. Work some organic fertilizer into the soil before planting or sowing the seeds.

Avoid using potting mediums that are too rich in nutrients. While nutrients promote leaf production, too many nutrients can harm the oil content and aroma of the leaves.

You should also avoid planting in overly acidic soils. A slightly acidic to neutral soil with a pH of 5.5 to 7.5 is best.

Following germination water the plants regularly. While the plants are actively growing you should not allow the soil to dry out. This is particularly important during warm or hot spells.

Aim to keep the soil evenly moist. Before watering, stick your finger into the soil to check how wet it is. A soil moisture sensor can also be used. The topsoil layer should be dry before watering.

When you water your plants, only water the soil. Try to keep the leaves as dry as possible. Wet leaves, particularly when exposed to cool temperatures, are prone to developing fungal diseases such as powdery mildew.

During the growing season apply a balanced liquid fertilizer diluted to half its strength every two weeks. You can also fertilize the plants with a homemade compost tea,

Pinch back or prune basil plants lightly every few weeks.

If you want to learn more about cultivating a productive plant, our in depth guide is a great place to start.

When to Prune Basil

For the best harvest, prune basil early in the morning as soon as the dew has dried. At this point the leaves are packed with the essential oils that give the plant its distinctive flavor and fragrance.

You can also prune basil in early evening, before the evening dew sets.

Learning how to prune basil starts early, when the plants are young. This encourages a branching habit to form early on.

How to Prune Basil 

Before learning how to prune basil you will need garden scissors or pruners. These should be sharp and clean. Take the time to properly clean your tools before and after using them. This helps to prevent the accidental transfer of disease or infestation between plants.

Learning how to prune basil can be divided into a series of simple steps.

1 Pinching Back the Stems

If you are growing from seed, allow the plants to reach a height of 6 to 8 inches. At this point the plant should have 3 to 4 sets of opposite leaves on its central stem.

Use a garden scissors to cut back the central stem to around a quarter of an inch above either the top or second set of leaves.

The central stem, at this stage in the plant’s development, tends to be soft and slender at this point. For this reason I find it easier to use garden scissors or small pruners to trim the plants, however you can also pinch the stem out with your thumb and index finger.

From the pinched out point on the central stem two new stems will emerge.

Start pruning when the plants are small. This encourages a bushy specimen to develop.

2 Pruning Out the New Stems

Following pinching out the central stem, allow the two new stems to develop. When these new stems have each produced several sets of new leaves they can be pinched out or cut back to half their length.

Remember, when pruning, to always cut around a quarter of an inch above a set of leaves. Use sharp scissors or pruners to make a clean, precise cut.

The leaves on the cut away stems can be picked from the stem and used to add flavor to various culinary dishes.

3 Prune Basil Regularly

During the spring and summer months, continue to prune basil plants as described in the previous stage.

Remember that for every stem you prune, two new stems will develop, creating a bushier plant. This, in turn, provides you with even more leaves to harvest.

4 Pruning Flowers

During the hottest months, when temperatures regularly exceed 80 ℉, plants can set flower and go to seed. While flowers are both edible and attractive to pollinators, allowing plants to set flower slows growth and causes the flavor of the leaves to deteriorate.

Stressed plants tend to flower sooner than happy, healthy specimens. Place your plants in a sunny position in well draining soil and water regularly. These simple steps help to delay flowering for as long as possible.

When the buds do appear, cut them away or pinch them out. This helps to focus the plant’s energy on growth and producing a larger yield of leaves.

Once buds start to appear, check the plants for new buds every day. Make sure, when removing, that you remove the entire bud. Allowing even the smallest part of the bud to remain on the plant can cause the stem to cease leaf production.

Flower buds typically form on a stem at the juncture of two leaves or stems. On Genovese cultivars the buds typically form on the tip of shoots. Initially resembling a dense cluster of small leaves, the bud opens to reveal small white flowers.

Thai cultivars produce purple buds. Greek cultivars are typically tight, tidy plants. Here the small buds form at the tip of the shoot. These are easily pinched away by hand.

Popular with pollinators, many people chose to prevent the plants from flowering. 

If you are unable to check the plants for a few days, or miss a bud and a flower forms, it is not a major problem. Simply cut the flower from the plant.

While the flowers can be placed on the compost heap, remember that they are also edible. They add both color and flavor when sprinkled over a salad. You can also place the fresh flowers in a small vase of fresh water to enjoy.

Should lots of flowers form, cut back the entire plant by half. This encourages new growth to form. The cut away sections have a range of uses such as making pesto.

5 End of Season Pruning

This is a warm weather herb meaning that it is not tolerant of cold temperatures. When night time temperatures fall into the low 40 ℉s black spots may develop on the leaves. Prolonged exposure to cold temperatures can also cause the plants to die back.

As fall approaches harvest the entire plant. The leaves can then be dried or frozen for use throughout the winter and early spring months.

How Not to Prune Basil

Do not just prune away the large, low leaves. These are the powerhouses of the plant.

The large leaves take in the most sunlight, enabling photosynthesis to occur and allowing the plants to take on the right nutrients. Removing these leaves harms the plant, slowing growth.

Pruning away the lowest leaves does not encourage branching or new leaves to form.

Do not remove the lower leaves.

Pruning the plants incorrectly can lead to just one central branch forming. It can also cause plants to become sparse or woody. Heavily pruning the plants incorrectly can also lead to stress and even death.

How to Preserve Harvested Leaves

While best used fresh, an excess of leaves, particularly common at the end of the growing season, can be stored for long term usage.

The two most common ways to store the leaves are either by drying or freezing them.

How to Dry the Leaves

Learning how to dry the harvested leaves is pleasingly easy.

If the harvested leaves are still on the stems, you can use some Garden Jute Twine to tie the leaves into small bunches and hang them up to dry.

Similar to drying lavender, this process of drying leaves is simple and easy. Simply hang them up in a warm room away from direct sunlight. It usually takes 10 to 14 days for the leaves to dry.

Once dried the leaves can be crumbled into jars for long term storage.

You can also dry the harvested leaves in a dehydrator or on a herb drying rack. A LQSURN Hanging Herb Drying Rack not only provides an effective way to dry all types of herbs, it also folds away for easy storage.

Harvested leaves can be stored for use over the winter months.

How to Freeze the Leaves

To freeze the leaves, remove them from the stems and place in a food processor. Drizzle some olive oil over the leaves to coat them before pulsing until they are coarsely chopped.

Remove the chopped leaves and place in labeled freezer bags. Lay the blags flat in the freezer to make the most of your space. Then, simply break off frozen chunks to use as and when you need them.

You can also store and freeze the chopped leaves in ice cube trays. Pesto can also be stored in this way, enabling you to simply add a frozen cube to your food as you cook.

Learning how to prune basil is a useful skill. Easy to master, correctly pruning plants encourages them to become a large and bushy part of the herb garden, producing lots of flavor filled, rich green leaves that can be used in a range of culinary dishes.