How to Grow Thyme Herb from Seed
- Scientific Name: Genus Thymus
- Hardiness Zone: Annual, Perennial Zones 5-10
- Days to Harvest: 30-40 days (from date of transplanting)
- Days to Maturity: 2nd Year
- Days to Germination: 14-28
- Seeding Depth: ¼”
- Plant Width: 12-18"
- Plant Height: 6-12"
- Growth Habit: Low-growing and trailing shrub
- Soil Preference: Average, loose, dry, well-drained
- Temp Preference: Warmer, 65-85°F
- Light Preference: Full sun
- Pests/Diseases: Susceptible to rot and mildew in overly moist, heavy, and poorly drained soil. Thyme does not have too many pests or insects and is generally seeded in the garden to help minimize pests.
- Availability: See All Thyme Varieties
Whether growing a culinary variety or a hardy ornamental crop, thyme is one of the easiest plants to maintain once established and grows so effortlessly that many species of Thymus are listed as invasive. Thyme is native to the mountainous crags and slopes of the Mediterranean and thrives in many grow spaces too sandy or dry for most ornamentals. Thyme is surely one of the most diverse and pervasive herbs cultivated with the genus Thymus hosting over 350 known varieties of thyme ranging from Mint, Elfin, Golden, Creeping, and the culinary staple, Common. While there’s no secret that it’s much easier to propagate thyme from cuttings rather than seed, growing thyme from seed allows growers to experience the breadth and diversity of all that thyme has to offer. Much like store bought basil or mint, thyme is usually only sold in a single variety, leaving the several hundred other varieties up to the home gardener.
How to Grow Thyme from Seed
- Optional cold stratification
- Cover with no more than ¼” soil
- Keep soil warm during slow germination
Although thyme seeds are very similar to lavender and rosemary seeds, they do not strictly require the same period of cold stratification as some other herbs. Cold stratification is simply a 2-6 week period in which seeds are stored in a freezer prior to spring sowing, imitating the same winter frost the seeds would have experienced if grown in the wild. While herb seeds lavender and rosemary are almost unanimously cold stratified in late winter, the jury is still out deciding whether thyme prefers the same conditions. Many gardeners swear that their thyme can’t grow without a period of stratification, while just as many others get the same results with a simple direct sowing. This discrepancy is likely due to environmental factors including humidity, heat, soil, and hardiness zones. Try growing thyme for yourself to decide whether a standard 2-6 week cold stratification is right for your climate.
Regardless of the cultivar, thyme is a warm weather full sun crop grown both indoors and out. Thyme seeds are best started indoors 8-10 weeks prior to the final spring frost. Plant 2-3 seeds deep per cell or about 5-6 seeds per square inch as a light seeding, eventually thinning out the strongest starts once true leaves emerge. Like many perennial herbs, thyme is known to be fairly delicate as a seedling, germinating anywhere from 14-28 days. Average and medium dry potting soil is more than enough to start thyme but be sure to transplant starts into sandy and well-drained soil in full sun. Harden off seedlings to the outdoors gradually, but soon, since even the best grow lights will never substitute full sunlight. Transplant healthiest starts 12-18” apart in the garden or one plant per planter.
All 350+ plus cultivars of Thymus are susceptible to root rot and mold from overly saturated, heavy, and poorly drained soils. Some of the most invasive and troublesome species of thyme are said to flourish in moist and cool soils, but the overwhelming majority propagated in the home garden thrive best when their soil is left to dehydrate. Thymus is native to the dry, shallow, and rocky soils of the Mediterranean hills and will thrive just as readily in any grow spaces able to offer the same substandard conditions. Thyme plants are so hardy that they will usually live their entire 5-6 year lifespan, provided they are not met with prolonged humidity, saturation, or shade. Thyme should not necessarily need supplemental fertilizer since it is a wide-spreading and invasive herb on its own. But, for an early boost to new spring plants, prepare soil with a light composting or worm castings before transplanting. Some thyme plants may benefit from a balanced and water soluble fertilizer once or twice throughout the season should leaves begin to discolor. Thyme can tolerate a wide range of soil pH from anywhere between 6.0-8.0.
- Less is more
- Drought tolerant
- Allow soil to dry between waterings
As mentioned, thyme thrives in the temperate and dry conditions found throughout the Mediterranean. Whether growing in the garden or transplanting to a pot, thyme will always require dry soil and dry roots to thrive perennially. Be sure that the top two inches of the soil is completely dried before watering, allowing the soil a chance to absorb moisture rather than sitting in a saturated pot. Overwatering is the biggest threat to thyme which is directly responsible for the development of mold, root rot, and fungus.
Is Thyme A Perennial?
Thyme is a wild and woody perennial known to live up to 5-6 years with proper pruning, watering, and sunlight. Just like its Mediterranean relatives lavender and rosemary, thyme is a perennial to grow zones 5-9 approximately. And although a warmer full sun Mediterranean native, common garden thyme is able to withstand a winter freeze by going dormant through the season. The winter dormancy will cause thyme to develop a thicker, woodier stem and base leaving much of the leafy vegetation too mature for flavorful culinary use until new growth in spring. Thyme is also popularly grown in convenient and moveable pots and containers so it may be easily brought indoors to overwinter. Both culinary and ornamental varieties can be left outside in subfreezing conditions, but overwintering thyme indoors in a temperate 60°F environment will keep your plant tender, aromatic, and delicious.
Thyme in Winter
- Dormant in freezing winters
- Frost hardy to 0-10°F
- Prune back in early spring
Wild mountain thyme (Thymus serpyllum), also known as Breckland thyme or creeping thyme, is no stranger to the snow pack from a frosty winter season spent entirely outdoors. Some of these more wild varieties have been found to endure winter conditions even as low as -20°F, although we don’t want home gardeners to expect the same tolerances from their common thyme (Thymus vulgaris). Because thyme is grown for its stems rather than blooms, it can be harvested in the middle of winter regardless if you live in the warm tropics of zones 9-10 or even in the mountainous freeze in zone 5-6.
Growing Thyme in Pots
As a native to the dry and sandy slopes of the Mediterranean, thyme actually prefers and thrives from the reliable drainage offered by container gardening. Pots, planters, and containers, especially clay-based terra cotta, can be notorious for excessive soil dehydration and herbs like angelica, chervil, and parsley traditionally do not thrive in containers. If grown indoors, be sure to allow thyme a minimum 6 hours of a sunny window each day, preferably more if possible. Plants can be conveniently moved throughout the day and seasons to best track sunlight for optimal growth. Thyme grown in pots thrives both indoors and out and is traditionally brought back in to safely overwinter. Although potted thyme is able to go dormant and withstand a winter freeze, it is still ideal to be brought back indoors to keep thyme from becoming too woody and mature for culinary use.
How to Care for Thyme Plants in Pots
- Naturally thrives in pots
- Overwatering is the greatest threat
- Try terra cotta pots for best drainage
Before transplanting thyme seedlings to a pot or container, prepare the soil with equal parts sand, perlite, and even a light composting in addition to standard potting or gardening soil. The sand and perlite provide improved drainage while the compost, not only assisting with drainage, also amends the soil to best help bring the thyme seedlings to maturity. Thyme generally shouldn’t require much fertilizing other than some composting or worm castings when first transplanted. While pots and containers, especially terra cotta, are preferred for semi-arid crops, these plants are still at risk for overwatering because the inexperienced grower is likely to keep the soil moist and saturated out of fear of dehydrating their developing herbs.
Growing Thyme Indoors
Culinary thyme is popularly grown indoors as a fragrant seasonal windowsill herb while many ornamental varieties are tended to as perennials brought in to overwinter at the end of each season. Thyme plants actually thrive indoors because of the well-drained pots and containers they’re grown in are ideally suited for a drier and sandy soil preference. As mentioned, thyme seeds are generally best if germinated indoors about 8-10 weeks prior to the final spring frost, but should still be supplemented with plenty of sunlight once true leaves begin to emerge. Just like outside, thyme grown indoors requires a minimum 6 hours of sunlight each day, although as much as possible is always preferred. Thyme prefers an average indoor temperature of about 60°F and loose, dry, and well-drained potting soil, only watering when the soil completely dries.
Proper and regular pruning is one of the most guaranteed ways to help your thyme plant realize its full 5-6 year potential. Thyme is a low-growing and quickly spreading herb widely known to be invasive but, with regular pruning, is easily tamed in any garden bed or patio planter. Pruning thyme is really no different or more challenging than harvesting thyme, as each stimulates the plant to produce abundant vegetative growth. If growing thyme exclusively for culinary purposes, then routine pruning will keep your stems flavorful, fragrant, and tender as opposed to them developing woody, less herbal notes from unpruned plants. All 350+ varieties from genus Thymus are pruned very similarly to other perennial herbs such as rosemary and sage and any experience with pruning just one herb should give you more than enough confidence to try thinning out your own homegrown thyme.
When to Prune Thyme
- After winter dormancy
- Throughout season as needed
- Late summer in regions with warm winters
Because thyme grows so rapidly and weed-like, there is almost never a bad reason to prune thyme. Regardless of hardiness zone, pruning thyme as needed throughout the season will ensure that your plant adapts and shapes to the grow space provided without threat of overrunning the garden. Growers in colder and more northern regions are generally accustomed to pruning back their perennial herbs in the spring after a long, cold winter and then throughout the season as necessary. If growing in a climate with routinely freezing winters, be sure not to prune thyme plants past late summer so they have a chance to develop additional growth and woodiness to best defend against winter frost.
How to Prune Thyme
- Prune about ⅓ of green growth
- No more than 20% of total plant
- Do not prune down to bare stems
Depending on the size and age of your thyme plant, pruning directions will adjust. Younger plants that have yet to develop a woody base can be pruned down to nearly 80% from the original size, while larger plants should only be pruned of about 20% of their tender new stems, never the wooded base. Using garden shears or scissors, simply give your thyme plant a “haircut” to evenly round and shape it, being sure to only ever clip from the softer newer growth. Pruning is only difficult the first time you do it.
Along with other woody perennial herbs lavender, rosemary, and sage, all 350+ species of the genus Thymus are easily propagated and cloned from cuttings. Propagating thyme from mature cuttings is simple and widely preferred to starting plants from seed. If you have any experience with growing just one herb from a cutting, then that should be enough for you to confidently try thyme from a cutting. When cloning and propagating thyme from established and store bought plants, you inevitably limit your selection because most nurseries will only carry one or two of the most common varieties of each herb. To truly experience the diversity of thyme, we invite you to try propagating from both seed and cuttings to ensure that your thumb is the greenest! Experienced gardeners will often harvest, prune, and propagate their herbs all from the same cuttings.
How to Grow Thyme from Cuttings
1. Depending on size and age of the plant, an ideal selection for thyme propagation is to cut the top 5-8” of a fresh young stem with plenty of soft green and no signs of flowering.
2. Take the clipping and strip about half of it bare of its leaves. Most soft cuttings should be about 5-8” long, stripping exactly half of the sprig for rooting.
3. The final step of propagating thyme from cuttings allows for two different methods to root the new cutting. The simplest method simply has you plant the bare end of the cutting into soil, allowing the remaining leaves to collect light for establishing new root structure. However, some gardeners prefer to root thyme cuttings in a glass of water by saturating the stem up to its leaves. Once roots are established in 3-4 weeks, the thyme clone can be safely transplanted to soil.
4. If propagating thyme hydroponically in a glass of water, be sure to change out for fresh water and a new glass every 5-7 days to avoid mold. If propagating thyme cuttings directly into soil, rooting hormones and gels are popularly used to incite growth, but are not required.
Thyme Companion Planting
Many of the most common aromatic herbs are widely believed to help deter small garden pests due to the pungent oils and chemicals contained in their leaves. While gardeners no doubt revel in the scent of fragrant homegrown herbs, it is these aromatics that keep gardens uninviting and somewhat toxic for small enough insects. Chemical extracts of the oils and terpenes from these herbs are popularly used in both topical bug sprays and organic garden insecticides. Gardeners will often plant thyme alongside the other woody perennial herbs such as rosemary, lavender, and sage for the mere convenience that they all require nearly the exact same grow conditions. Shown to significantly help reduce cabbage worms, garden thyme is a choice companion crop to keep near any cruciferous vegetables as well as with tomatoes, eggplants, and berries.
Many plants that emit naturally repelling chemicals are often believed to be more effective when directly grown in the garden rather than a container. When grown in the garden bed, plants like rosemary and marigold that emit naturally occurring pesticides are able to establish these chemicals in the soil to best mitigate pest problems. However, when grown in a separate pot or container, rosemary is only able to emit its robust fragrance and inhospitable terpenes rather than permeate them throughout the soil.
Not typically grown for flower production or fresh cut arrangements, but thyme still boasts some of the iconic lavender florets of the seasons. Thyme is a trailing and wide-spreading herb that grows ideally as part of a ground cover, garden lining, or xeriscaped property, producing countless ¼” blooms. And while most cultivars of thyme such as French or creeping produce pale white lavender florets, some exclusive varieties such as golden thyme are brimming with countless yellow blooms, appearing similar to another arid and rocky favorite, golden sedum. To allow the most amount of flower production, do not prune thyme until after going to flower. Herbs such as thyme, sage, and rosemary which are generally kept from going to flower are widely known to attract an abundance of pollinators and beneficial insects to the garden.
Culinary thyme is always best harvested from softer, greener, and more tender stems, while keeping mature and woody growth still attached to the plant. Thyme is a low-growing trailing herb that only reaches about 12” tall at full maturity, leaving about 5-8” of upright growth suitable for flavorful and tender culinary use. Unlike more delicate herbs such as arugula, basil, and mint which can be gently harvested with your fingertips, thyme is far more woody and will require scissors or gardening shears to remove any cuttings. Harvesting and pruning thyme essentially share the same fundamentals and each require a little less finesse than others. For optimal flavor, harvest thyme stems just before the plant goes to flower.
When to Harvest Thyme
- Year-round as needed
- Spring and summer in cool regions
- Prune, propagate, and harvest together
How to Harvest Thyme
- Use scissors or shears, never pull
- Harvest the top ⅓ of non-flowering stems
- Same as pruning, cut above the woody base
Harvesting and pruning thyme each share the same steps and are often performed at the same time as one another, harvesting your delicious pruning cuts. Whether harvesting thyme, rosemary, or sage, you can always depend on the most fragrant and herbal stems to be on the newest 5-8” of growth, generally appearing much more green and tender than the heavily wooded base. Newer plants in their first or second year can be harvested or pruned more drastically, even as much as 80% of total growth. Never harvest any stems that have gone to flower and, for more help, check out our section on Pruning Thyme.
Thyme leaves are very thin, minor, and should even begin to air dry as soon as they’re clipped from the plant. Although food dehydrators and ovens are commonly used to dehydrate other herbs, thyme is arguably best when left to air dry, either traditionally hanging upside down, left out on the kitchen counter, or stored in a Mason jar to be used when necessary. Thyme is just as easy to dry as any other herb, requiring nothing more than a little patience. Organic homegrown thyme from seed will only require a light rinse before dehydrating, while store bought thyme should always be vigorously washed to fully rid the cuttings of pesticides and chemicals that are almost guaranteed to have been sprayed sometime during the commercial growing process. Depending on method, thyme should be completely dehydrated within 14 days and ready to be ground for spices, teas, and potpourri.
How to Dry Thyme
Hang Dry: Cut about 5-8” of newest growth per stem and then bundle together. While larger plants will yield longer stems, still harvest just the tips for best flavor. Hang the thyme bundle upside down in a dry, cool, and well-ventilated area for 7-14 days until small, pointed leaves are brittle and no longer pliable.
Oven Dry: Thyme stems can be easily placed on a baking sheet and dehydrated in a convection oven at 175° F for 10-15 minutes or until leaves and stems are brittle and have lost color. After 10-15 minutes, turn off the oven and allow thyme stems to remain in the oven for another 40 minutes, leaving the oven door open to cool.
Food Dehydrator: Herbs, fruits, and flowers are ideal for countertop food dehydrators for reliable and thorough drying. Food dehydrators feature step-by-step instructions for herbs and is the preferred method for many cooks and home gardeners. Many herbs such as lavender should only take about 2 hours in any household food dehydrator.
Types of Thyme
The genus Thymus is host to more than 350 known species of thyme found naturalized all over the world and are all widely regarded as some of the most tenacious herbs known. While the most invasive and wild varieties of thyme are known to tolerate some saturation and humidity, the overwhelming majority of thyme species all share the same seeding, soil, and watering requirements. Propagating one variety of thyme will surely educate and encourage you to try any other cultivar of thyme or similar semi-arid herbs. Because of the staggering amount of species within Thymus, there is often confusion as to the common and generic names of many types of thyme, since many share the same name and scientific name. Growing thyme at home allows you to learn subtle differences in leaf shape, color, and flavor for yourself.
Common Thyme: (Thymus vulgaris) - The most popularly grown cultivar of thyme and found in nearly every nursery, greenhouse, and herb garden. Sometimes known as German thyme or simply garden thyme, Thymus vulgaris is the overwhelming choice for culinary thyme since it is argued to have the most distinguished flavor, fragrance, and stems. Although very similar, German thyme varies greatly from both French and English thyme.
Creeping Thyme: (Thymus serpyllum) - Also known as wild thyme or Breckland thyme, creeping thyme is arguably the most naturally widespread cultivar of Thymus. Celebrated for its hardiness, blooms, and minimal upkeep rather than culinary value, creeping thyme is traditionally grown as an ornamental in rock gardens, walkways, and xeriscaped yards. Allow creeping thyme to go to flower for stunning and vibrant purple and lavender blooms.
Benefits of Thyme
Thymol, the active oil in Thymus vulgaris, is a proven antimicrobial and is a primary ingredient in several medicinal solutions helping to treat various fungal infections including tinea, ringworm, and hookworm. Thymol is also a well-known antiseptic that has been popularly used in several commercial brands of mouthwash including Listerine, and is still the active antimicrobial in Johnson & Johnson’s toothpaste brand Euthymol. Pure thyme oil can still be applied as a topical and all-purpose disinfectant. And, as mentioned above, the same beneficial and fragrant oils used in antiseptics are believed to be responsible for warding off pests and insects from the garden as an essential companion plant to cruciferous vegetables, tomatoes, and eggplants. Just like any fragrant herb, thyme has traditionally been credited for its soothing, savory perfume which can relieve any stale room with all-natural aromatics. If nothing else, keep your favorite plant on the kitchen counter for effortless indoor harvesting.
Traditional thyme tea can be brewed from garden fresh sprigs just as readily as it is brewed from dried leaves. As a proven antioxidant, thyme leaves are popularly brewed with other medicinal herbs rosemary and peppermint for the most potent anti-cold herbal tea. Thyme herbal tea is widely believed to help remedy overall stress, pain, anxiety, and inflammation; popularly brewed as a subtle but energizing tea. Aside from soothing aromatics, rosemary has been found to be rich in antioxidants, antimicrobials, and anti-inflammatory compounds while showing evidence that it may help lower blood sugar, improve mood and memory, while supporting brain and vision health.
How to Make Thyme Tea
1. Using any type of tea infuser, satchel, or tea bag, add about 4 tsp of either fresh or dried thyme to every 8 oz of boiled water.
2. Allow thyme to steep for about ten minutes. Done!
Be sure to completely strain any thyme leaves from the tea before drinking to avoid any bitterness. Try dried thyme leaves with ginger root, licorice root, sage, and gingko for a truly potent blend.