How to Grow Thyme Indoors

potted thyme

The Spruce / Cori Sears

Thyme is a wonderful and versatile perennial herb—there are almost endless ways to use its fragrant leaves in everything from salad dressings and marinades to sauces and rubs. Originally native to southern Europe, thyme can be grown successfully indoors or outdoors, needing only basic attention in order to thrive. Though slow to germinate from seed, thyme's upright woody stems can grow to be between 6 and 12 inches tall in a single season, providing gardeners with plenty of delicious herbs to enjoy fresh or to dry for use all year long.

This well-loved herb also has a storied history when it comes to both spiritual and medicinal purposes. In the Roman era, thyme was thought to be an antidote for poison and was commonly consumed both before and after meals as a way to ward off any illness. It was also associated with courage and bravery and gifted to soldiers before going into battle as a means of protection or respect or burned at home to purify from spirits. In modern days, thyme now has a place in our kitchens and medicine cabinets—thymol, a chemical compound found in thyme, is an ingredient in mouthwash, medications, and sanitizers.

When grown as in an indoor plant, thyme can be planted at any time—from seeds, from potted nursery starts, or from divisions of existing plants.

Botanical name Thymus vulgaris
Common name Thyme, garden thyme, common thyme
Plant type Herbaceous perennial
Mature size 6–12 in. tall, 6–12 in. wide
Sun exposure Full sun
Soil type Sandy, well-drained
Soil pH 6.0–8.0 (slightly acidic to slightly alkaline)
Bloom time Summer
Flower color Purple
Hardiness zones 5–9 (USDA)
Native area Northern Mediterranean regions
Toxicity Non-toxic
potted thyme
​The Spruce / Cori Sears

How to Plant Thyme

As far as herbs are concerned, thyme is one of the easier plants to grow. In outdoor gardens, it's frequently used in xeriscaping in hot, dry locations where other plants have trouble thriving. It's hardy in USDA zones 5 to 9, and can even tolerate light frosts. When growing thyme indoors, the biggest challenge you'll face is ensuring the plant receives consistently bright light. Beyond that, care instructions for thyme are pretty straightforward (average soil, average watering, and average temperatures, among them), making it a great indoor herb for novice gardeners to start out with.

Thyme Care

Light

Thyme is a well-known sun lover, preferring to be planted or placed in a spot with access to full light nearly all day long. A bright windowsill that gets around eight hours of sun a day is ideal, but if your home is rather shaded or you're looking to keep your thyme thriving through the darker winter months, a snug spot under some florescent grow lights will work too.

Soil

Soil is perhaps the most important element when trying to grow thyme successfully. Whether you choose to do so indoors or out, select a soil mixture that is very dry and well-draining, as thyme is particularly susceptible to root rot and overwatering. Sandy mixtures are your best bet—if you choose to use potting soil you have laying around, cut it with a bit of gritty sand or gravel to ensure water moves through the soil quickly. A pot with ample drainage is also important, and those made of clay or terracotta can be beneficial in wicking away extra moisture from the soil. When it comes to the pH of the soil, a thyme plant isn't picky—it can thrive in a wide range of pH values ranging from 6.0 to 8.0.

Water

Once established, thyme plants are drought-resistant and often prefer to be under-watered rather than over-watered. Wait until the soil is completely dry, then saturate your thyme plant, allowing it to dry out again completely before giving it another watering. Keep in mind, thyme will flower but unlike other herbs, this is not a sign of overwatering or "bolting"—it will continue to thrive beyond blooming as long as you trim it back to promote new growth.

Temperature and Humidity

Thyme will thrive best in a hot, arid climate that mimics its Mediterranean roots. As best you can, strive to maintain temperatures in your home between 60 and 80 degrees Fahrenheit, taking care to keep humidity to a minimum. (That means keeping your plant out of rooms that tend to be more humid, like kitchens or bathrooms.)

Fertilizer

How's this for simple: Thyme actually prefers soil that lacks nutrients, so frequent fertilizing is not necessary. This also means that the herb is best planted in a pot or container by itself, as mixing it with other herbs will likely make the soil too rich for it to thrive properly. If you do want to give your thyme a boost, feed it with a diluted liquid fertilizer early on in its growing season—choose an organic fertilizer if you hope to cook with or eat your herb.

Thyme Varieties

As one of the world's oldest aromatherapy and medicinal plants, there are many varieties of thyme. While common thyme tends to be the most popular with gardeners and cooks alike, there are plenty of other readily available varieties that offer up both unique flavors and different appearances. Other popular plants include:

  • Thymus citriodorus: Also known as archers gold, this thyme varietal grows closer to the ground, often resembling a mat or carpet once established. As its name implies, its bright yellow-green leaves boast a distinctly lemony scent.
  • Thymus 'Silver Queen': A compact and busy variety, silver queen thyme is known for its greenish-gray leaves and rich red stems. It's often used to edge pathways or fill cracks in stone patios.
  • Thymus herba barona: Also known as caraway thyme, this variety has a similar taste to its cousin herb and is native to Sardinia and Majorca. It's more vine-like in appearance, often creeping down the sides of plant beds or pots.

Harvesting Thyme

Like outdoor plants, indoor thyme plants can be harvested at any time once they are established. Simply off the stems any time you need the herb for cooking.

How to Grow Thyme From Seed

Sow thyme seeds on the surface of a sterilized seed starter mix in a tray, and place it in a bright location at about 70 degrees Fahrenheit. Seeds can remain on the surface of the soil, or just barely covered. Once the seedlings sprout (it takes 14 to 28 days), they can be carefully transplanted into their final pots (or into the ground, if you're planting in the garden).

How to Grow Thyme in Pots

Standard potting soil is too rich and moist to be ideal for thyme, so add in plenty of sand or another gritty material to make the soil dryer and more porous. Plant thyme in a pot with good drainage to keep the roots from soaking in moisture. Water the plants only when the potting soil becomes thoroughly dry. Indoor plants should be grown in the sunniest location you can find—or under bright grow lights.

Potted plants can become woody after three or four years, at which time you should remove, separate, and replant the smaller pieces in separate pots and fresh potting mix.

Propagating Thyme

Thyme can be propagated from the division of mature plants. To do so, remove the mother plant from its pot, teasing apart the root ball and stems until you form two or more smaller plants. Plant each division in its own pot, allowing it to rest a week before watering. It's important to note that thyme isn't typically successfully grown from propagation—it's usually easier to discard older, woody plants and buy new thyme plants instead.

harvesting thyme
​The Spruce / Cori Sears

Common Pests/Diseases

Though easy to care for, thyme is susceptible to a few pests and diseases that, although not typically fatal, can be annoying for gardeners to deal with. The first, gray mold, can develop due to water-soaked leaves. Characterized by gray fuzzy spores present on the leaves of the thyme plant, the only remedy for grey mold is to remove the infected stems or throw out the plant. Thyme is also prone to whiteflies and mealybugs when kept indoors. To prevent and treat infestations, use neem oil where necessary, being careful to follow label instructions.