There's Something Special About Basil

Garden Friend - I thought you might like to read my recent garden article that ran in The Denver Post about growing and using basil.

Link to The Denver Post article, click HERE. The full article is below.

There’s something special about growing your own basil in Colorado

Here are some of the many faces (and uses) of this wonderful herb

There are scores of cultivated basil varieties available, including Thai basil, lime basil, lemon basil, sweet basil, Napolitano, Genovese and dark opal basil. (Betty Cahill, Special to The Denver Post)

By Betty Cahill | Special to The Denver Post

June 11, 2024

One of the many pleasures and essences of the outdoor growing season is basil. What other edible herb breathes so much flavor and summer sunshine into a dish? If basil conjures romantic dreams of dining on a hilly Tuscan terrace, then join the throngs of others who find basil to be, if not No. 1, then right up there as the most popular summer-grown herb in America.

Basil’s unique, intoxicating flavor might be described as spicy-sweet floral with undertones of pepper and mint and, according to some palates, mild anise with hints of clove. Basil’s essential oils live in microscopic sacs on parts of the plant. The sacs are ruptured (in a good way for smell and taste) each time the plant is chewed or rubbed.

There are scores of cultivated basil varieties available, including Thai basil, lime basil, lemon basil, sweet basil, Napolitano, Genovese and dark opal basil. Seeds offer more selection than transplants.

Basil is in the botanical family group called Lamiaceae, which includes the large collection of plants that are characterized by square stems and opposite leaves. Other herbs in this family include rosemary, thyme, mint and lavender. Basil leaves range in color from green to purple or a mixture of the two. Leaves vary in size, from small as a dime to as large as an open hand. Some varieties have smooth leaves; others are hairy, even puckered. The flowers are located in the axils of the leaves or in very loose spikes with the flowers separated along the stem. Flowers are either lavender or white.

Seeding directly outdoors or in containers

To prevent flowering, begin pruning basil stems as early as the six to eight-leaf stage. (Betty Cahill, Special to The Denver Post)

Sowing the seeds directly into your garden beds or containers is the easiest method to start basil and plant enough for several dishes all summer long and to preserve leaves for fall and winter use. The three most important factors for germination and growth are soil quality, high nighttime temperatures and proper soil moisture. Warm soil is needed, as is warm ambient air. Soil and air temperatures should be 55 consistent degrees or more at night. Seeds sown too early may rot in spring rains; transplants can stunt or stop growing with cool day or nighttime temperatures.

Prepare the outdoor soil bed or location as you normally would for seeding and transplanting other vegetables outdoors. Rake the area carefully to create a fine, crumbly seedbed free of rocks and debris. Scatter seeds as evenly as possible over the soil (1/8 inch deep) so they’re close together; cover lightly with more soil and water.

Use new sterile potting soil when seeding into containers, then follow the same instructions as in-ground planting. Here’s a quick video primer on seeding in containers.

Water regularly so the soil around the seeds does not dry out. Seedlings emerge in five to 10 days. The warmer the temperatures, the quicker seeds germinate. After planting, water thoroughly to keep the seedbed moist. Use a watering can or a hose with a fine spray to water gently so seeds don’t wash away or dislodge the new seedlings. Seeds are great value compared to transplants, so keep plants coming by seeding every couple of weeks in the summer through August.

To utilize the basil plant for culinary use, the plant must not be allowed to flower ever during the growing season. (Betty Cahill, Special to The Denver Post)

The first leaves on basil seedlings are D-shaped “nurse” leaves that will be replaced by the normal foliage. Once the seedlings have their first or second set of true leaves, start thinning to the size of the area in which you wish to grow the plants.

Seedlings should be thinned until the plants stand 3 to 4 inches apart. Use scissors to snip off extra seedlings at soil level; pulling them out could injure the remaining, nearby seedlings. Toss any thinned basil in your mouth for a jolt of flavor.

If you’re seeding outdoors as micro-greens (one of my favorite methods of growing basil)m then there’s no need to thin the plants: Let them grow densely together and harvest as you would with growing microgreens indoors, when they are young and small.

Transplanting to the garden or in containers

Harden off all transplants that have been growing indoors. Site the plants or container where they will receive the most sun and air circulation. Space plants 3-4 inches apart in the ground or in the container. Larger plants like African Blue (grown more for ornamental then culinary use) may need up to 3 feet of spacing. Plant at the same level they were growing in the container. Water with a soft mist sprayer so plants don’t fall over. Fertilize every two weeks with half-strength liquid fertilizer.

Growing more basil from cuttings

If you’re seeding basil outdoors as micro-greens (one of my favorite methods of growing basil)m then there’s no need to thin the plants: Let them grow densely together and harvest as you would with growing microgreens indoors, when they are young and small. (Betty Cahill, Special to The Denver Post)

Any basil type can be grown from a stem tip cutting. It can all be done very inexpensively with a cup of water in a short glass. Use cuttings from tips of nonflowering stems on vigorous plants that have 8-10 leaves. Plants grown in full sun produce the best cuttings, so this procedure makes sense to propagate more plants for your outdoor garden or to share with friends. Make sure cuttings are taken from disease- and bug-free plants.

Procedure: Cut stems about 4 inches long using sharp, clean scissors. Strip the leaves from the lower half. Fill cups with water so that only the bare stems are immersed. Fit three or four cuttings in the cup or jar.

Place on windowsill that receives plenty of light. Change the water daily to prevent bacteria buildup. Purple basil roots slower than green basil. Green will grow roots in 1-2 weeks. Once well rooted, plant them in a 5- to 6-inch container, one cutting per pot. Punch drainage holes in the paper or plastic cup. Carefully add the rooted stem cutting to the cup with some sterile potting soil on the bottom and then add soil around the cutting. Place the potted cuttings on a sunny windowsill or under grow lights for a week or two.

Care for them just as transplanted seedlings. In a few weeks, they will be ready for transplanting outdoors in the ground or a container.

Pest control

Unfortunately, Japanese beetles find basil leaves to their liking. One easy, inexpensive prevention tip is to grow plants under lightweight mesh covers or bridal veil. Basil does not need pollination when grown for leaf use so covers can be used all season. If growing basil for the flowers, don’t cover; hand-picking and drowning beetles may be necessary.

Harvesting basil

Basil has a one-track mind: to sprout, grow, flower and set seed to reproduce. To utilize the basil plant for culinary use, the plant must not be allowed to flower ever during the growing season. Flowering changes the leaf flavor — and not for the better. To prevent flowering, begin pruning basil stems as early as the six to eight-leaf stage. For culinary use, the goal is to keep multiple plants only growing 10 or fewer sets of leaves.

Fresh leaves tossed into sauces, salads, caprese and pesto are never-miss favorites. (Betty Cahill, Special to The Denver Post)

Basil will only grow so many leaves prior to flowering, and cutting flowers after they have formed does not stimulate new leaves; it encourages more flowering.

When harvesting, use clean scissors and cut directly above a set of two leaves. Let two to four leaves remain on the stem. In a short time (two to three weeks) the stem will grow out stimulating side growth, making the plant fuller and more leaf plentiful for further harvesting.

In addition to growing basil for culinary use, also consider growing other pretty varieties and allow them to flower for arrangements and your enjoyment. Holly’s Painted, Anise, Cinnamon, and lemon basils look wonderful in floral arrangements. Bees and other pollinators also love flowering basil.

Always harvest basil when you are going to use it immediately and avoid harvesting wet leaves.

Store cut basil in a jar of water in the refrigerator; it should last 7 to 10 days.

Using fresh basil

With so many basil types, flavors vary, too. Often the name of the basil indicates how to match the food being prepared, so experiment and have fun trying new dishes with your home-grown plants. Fresh leaves tossed into sauces, salads, caprese and pesto are never-miss favorites. Branch out this summer and prepare basil vinaigrette, basil butter and basil jelly. Recipes are easily found online.

Preserve: Much of basil’s flavor is lost when freezing, but if there is an abundance of basil near the end of the growing season you can try freezing a whole sheet of leaves, and then pack them between wax paper. This makes for easier leaf removal for recipes. Add frozen leaves directly to soups and sauces as needed.

Freeze chopped basil with olive oil for future pesto or flavoring for other dishes. Do not add the garlic, pine nuts or cheese until after thawing the chopped pesto and oil. Then also add some fresh parsley to improve the green color.

Drying basil is easy. Whole dried leaves taste better than crumbled leaves. Hang 3 to 5 stems bundled with twine or string in a ventilated room away from the sun. Or dry individual leaves on screens in a room, porch, shed or attic. Turn the leaves every few days. It will take 8-10 days to dry. When using an oven, set the temperature to 150 to 200 degrees for 3-5 minutes; if over-dried, the leaves will taste bitter and turn brown. Pack whole or crumbled leaves in clean jars with tight lids. Label and store; they last about a year.

Betty Cahill speaks and writes about gardening in the Rocky Mountain Region.