Thyme is a wonderful and versatile perennial herb that can be successfully grown indoors, needing only basic attention 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 fresh herbs or to dry for use all year long. When grown as an indoor plant, thyme can be planted at any time of year from seeds, potted nursery plants, or divisions of existing plants.
|Botanical name||Thymus vulgaris|
|Common name||Thyme, garden thyme, common thyme|
|Plant type||Herbaceous perennial|
Can You Grow Thyme Indoors?
As far as herbs are concerned, thyme is one of the easier herb plants to grow. When growing thyme indoors, the biggest challenge you'll face is ensuring the plant receives consistently bright light. Beyond that, caring for thyme is straightforward (average soil, average watering, and average temperatures, among them), making it a great indoor herb for novice gardeners to grow.
How to Grow Thyme Indoors
Thyme is a well-known sun lover preferring to be planted or placed in a location with access to full sunlight nearly all day long. A bright windowsill that receives eight hours of sun per 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.
Temperature and Humidity
Thyme is native to the Mediterranean region, and it will thrive best in a hot, arid climate. 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 away from rooms that tend to be more humid like kitchens or bathrooms).
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 that thyme will flower, but unlike other herbs, this is not a sign of overwatering or bolting—it will continue to thrive beyond blooming if you trim it back to promote new growth.
How's this for simple: Thyme actually prefers soil that lacks nutrients, so supplemental fertilizing is not necessary. This also means that the herb is best planted in a pot or container by itself because combining 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. Pay close attention to the fertilizer packaging to ensure you add just enough to help, not hurt, your thyme plants.
Pruning and Maintenance
Like outdoor plants, indoor thyme plants can be harvested at any time once they are established. Simply snip off the stems any time you need the herb for a recipe.
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.
Container and Size
Thyme doesn't need much room to grow, so a container as small as four inches in diameter can be enough room to grow young plants. Clay or terracotta pots might work best for this plant. Make sure the container has good drainage.
Potting Soil and Drainage
Soil is perhaps the most important element when trying to grow thyme successfully. 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 already have at home, 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. Thyme is not too particular about soil pH levels—it can thrive in a wide range of pH values ranging from 6.0 to 8.0.
Potting and Repotting
When a thyme plant begins to develop woody stems more than tender leaves and shoots, it's time to repot the plant. Carefully remove it from its container, then separate the pieces of the root. Choose the smaller pieces for transplanting into new pots. Choose small pot about four inches in diameter. Repot the plants with the proper mixture of potting soil, as described above.
Moving Thyme Outdoors for the Summer
Thyme thrives in full sun and makes an excellent outdoor plant. Move the pot outside when the temperature is consistently pleasant at 60 degrees Fahrenheit or above.
Thyme grown in containers can become tall, so place it in an area where high winds won't knock it over. Watch for pests throughout the growing season and treat them appropriately if they happen to show up. Becuse this is a culinary plant, use only organic treatments.
When to Bring Thyme Back Inside
Thyme loves a climate that mimics that of the Mediterranean, so bring it inside when the temperature drops enough to bring a bit of a chill. As a general rule of thumb, bring thyme plants indoors onto a sunny windowsill when the temperatures drop to around 60 degrees Fahrenheit.
How do you 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 with soil. 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).
Is it easy to propagate 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.
What plant pests are common to thyme?
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.