Growing Indoor Herbs

By Julie Christensen

Herbs are delightfully satisfying to grow because they’re quick, low-maintenance plants that offer a feast for the senses. Their bright leaves and colorful blooms add variety to a vegetable garden, while their scent and flavor enhance almost any fresh or cooked dish.

Sadly, the season for spontaneously plucking herbs out of a kitchen garden is all too brief. Most tender herbs, such as basil, die with the first fall frost. Perennial herbs, including mint, thyme and oregano, last a bit longer, but not nearly long enough. Several herbs, including cilantro and dill, go to seed as soon as temperatures rise unless you constantly replant them.

You can grow herbs indoors with a little extra care. They won’t grow as vigorously and the flavors and aromas won’t be as strong, but they’re certainly better than the dried varieties. Read on to learn how.

Indoor Herb Growing Basics

The first thing you need to understand about herbs is that they’re sun-worshippers. Most of them hail from the Mediterranean and they’re accustomed to bright sunlight and warmth. When growing them indoors, one of your biggest challenges will be giving them enough light. In early fall, you might get away with growing them in a sunny window with a western or southern exposure. By winter, though, even the sun coming through these windows will have only one-tenth of its outdoor summer intensity.

The first sign of a light deficiency is pale leaves and stunted growth. As the plants attempt to acclimate to lower light, their leaves turn brown and drop. In time, the entire plant will shrivel, wilt and die. Before herbs show signs of a light deficiency, rescue them and place them under fluorescent grow lights. You can buy commercial grow lights designed for indoor growing or rig your own inexpensive system. Place the herbs about 4 to 6 inches from the light and leave the light on for 8 to 12 hours daily.

Once you’ve conquered the light challenge, your next hurdle is providing proper moisture conditions. There’s a common misconception that herbs grow best in dry, poor soil. It’s true that in the Mediterranean, many of them do thrive in these conditions. In a pot in your home, though, the game changes. To survive indoor culture, herbs need a light, well-draining potting mix. Don’t use garden soil, which is too heavy and can harbor disease. To improve drainage, add additional perlite or sand to a high-quality potting mix at planting time.

Herbs grown as houseplants should be watered as soon as the soil surface feels dry. Plants grown in pots tend to dry out more quickly than those grown in ground so don’t ignore this task. Water the herbs until you see water coming out of the drainage holes.

Herbs grown in the garden rarely need additional fertilizer, but those grown indoors are another story. Fertilize them every three weeks with 1 tablespoon granular 10-10-10 fertilizer diluted in 1 gallon of water. Maintain this fertilizing regimen as long as the plants are growing vigorously. During the winter, herbs sometimes go dormant even under grow lights. If growth slows mid-winter but the plant looks healthy, it is probably entering dormancy. Cut back fertilizer applications to every six or eight weeks.

Starting Herbs Indoors

Grocery stores and nurseries carry young herb plants every spring, but herbs are simple to start indoors. By starting herbs indoors, you often can grow a wider variety of plants and you’ll save a bundle of money, as well.

Depending on the herb variety, start herbs indoors four to six weeks before the last frost. Fill peat pots, Styrofoam cups or seed starting trays with a light starting mix. Moisten the mix with water from a spray bottle. Plant the seeds, according to package directions. In most cases, you’ll cover them with a light sprinkling of soil. Cover the seed trays or pots with plastic wrap and store them in a warm location, such as the top of the fridge. Water them every other day or as needed so the potting mix stays slightly moist to the touch.

Once the seedlings emerge, remove the plastic wrap and move the herbs to a grow light or a sunny window. Continue to water them. Young seedlings can be planted outdoors when they stand 4 inches tall. Wait to plant tender annual herbs outdoors until after the last frost.

For more information on growing herbs indoors, visit the following links:

How to Grow Herbs Indoors During the Winter from the Christian Science Monitor

Growing Herbs Indoors from Penn State Extension

YouTube goes over the basics of potting your herbs for indoor growing.

Julie Christensen learned about gardening on her grandfather’s farm and mother’s vegetable garden in southern Idaho. Today, she lives and gardens on the high plains of Colorado. When she’s not digging in the dirt, Julie writes about food, education, parenting and gardening.