Why Your Basil Plants Are Getting So Leggy In The Middle Of Summer (And What To Do About It)

Basil (Ocimum spp.), a widely used herb that adds flavor to sauces, salads, main dishes, and sides, is native to Southeast Asia, India, and Africa. Different varieties vary in size, shape, and flavor, from spicy Thai (Ocimum basilicum var. thyrsiflora) to sweet (Ocimum basilicum), the variety found most often in the U.S. It can be harvested throughout its growing season, leaving the home cook with an almost endless supply of fresh herbs. Whether grown in the ground or in containers, as a culinary herb or an ornamental, basil should be fertilized sparingly. Too much will make your plants grow tall stems with few leaves, leaving them looking like they might walk right out of the garden.

Unlike oregano stems, which can be used in cooking, basil's legginess from overfertilizing reduces the harvest of tender, savory leaves. Ornamental basil is usually grown for its flowers and lush foliage, not its stems. Whether your motivation is culinary, ornamental, or both, have your soil tested before you plant basil. Buy a home test kit, DIY one, or send a sample to your local extension office or university agriculture department. Ideally, the soil will have a pH between 6.0 and 7.5. If the pH falls outside the ideal range, you can raise it by adding lime or lower it with aluminum sulfate and sulfur. Your local garden store should have what you need to do this.

Basil, hardy in zones 9 to 11, can be started indoors about six to eight weeks before the last spring frost, or sown directly outdoors in full sun and moist, well-drained soil once the danger of frost has passed. If you sow it outdoors, thin seedlings to about a foot apart once they've developed leaves. Basil benefits from having a 2- to 3-inch layer of mulch applied when the plants are several inches tall. Water the plants deeply once a week or more often in times of drought. Keep in mind that basil in containers will need to be watered more frequently.

Too much fertilizer produces leggy plants. Basil grown in the garden should be fertilized with a commercial 5-10-5 product once or twice during the growing season. Apply around three ounces per every 10 feet of row. Both outdoor container plants and indoor plants should be fertilized at half strength, every four to six weeks for indoor plants and three to four weeks for outside.

Another way to stop basil from getting leggy is to pinch off the flowers throughout the season. If your plant produces more than you can use, dry the leaves by hanging them in warm, dry air. Leave the flowers if you're growing basil as an ornamental, and at the end of the season, collect the seeds the flowers produce for future use.