How To Grow Thyme Indoors?
Growing potted herbs indoors is a great way to continue gardening during winter or when you don’t have outdoor growing space. One indoor herb that’s particularly easy to grow is thyme. But what are the specific growing needs of this plant, and how do you even get started?
To grow thyme indoors, you need a small, well-draining pot with porous soil, slightly alkaline conditions, and basic fertilization.
Published: January 2, 2023.
Thyme prefers dryer conditions, only requiring water when the top ½-inch of soil dries out, as well as a warm (roughly 70 degrees F) setting with full sun.
To learn more about the indoor growing needs of thyme, keep reading. We’re sharing details regarding choosing a plant pot, how to fertilize thyme, how to prune it, and when it’s time to harvest the herb.
Overview - Growing Thyme Indoors
When growing an herb like thyme indoors, there are specific growing practices you should follow. In this guide, we’ll be covering the following topics related to thyme growth and maintenance.
In these sections, we share tips regarding the types of nutrients that are best for this plant and the whole scope of growth - from planting to harvesting.
- What size and type of pot to use for thyme
- What type and amount of soil to use for thyme
- How much and how often thyme needs watered
- How much and what type of sunlight does thyme need
- The ideal temperature range for indoor thyme
- Fertilization requirements for indoor thyme
- How to prune thyme indoors
- How to harvest thyme grown indoors
For the sake of continuity, this article will deal strictly with growing thyme indoors, starting with an already established plant (rather than from seed).
One of the first steps you should take is to acquire an adequate indoor plant pot. The container should meet size and shape requirements that can meet the needs of a thyme plant’s root system. This ensures that the plant can properly intake nutrients and water.
Recommended Pot Size
Thyme is one of the smaller herbs you can grow indoors, so it needs a much smaller pot than, for example, rosemary.
The diameter of your thyme container should be at least 5-6 inches. And the pot should measure at least 4 inches deep to accommodate the soil, plant, and root system.
Recommended Pot Type
A basic, round plant pot is adequate for growing thyme indoors. Clay or terra cotta pots are ideal because they improve the drainage capacity of the pot. This is due to the porous nature of natural clay materials, whereas many glass and plastic materials are non-porous.
By increasing the drainage - including choosing a pot with drainage holes and/or a drainage tray - you can keep thyme dry. In dryer conditions, the plant thrives, avoiding diseases it’s susceptible to, like root rot.
Different types of plants require different types of soil, as well. While you might opt for cactus soil for a succulent due to its well-draining perlite and gravel content, thyme prefers slightly more moist soil.
You still want the soil to be well-draining for thyme, but you can opt for a more standard soil such as potting mix. The soil should have the following qualities:
- A small amount of gravel or drainage stones
- pH level between 6.0-8.0 (ideally above 7.0 for slight alkalinity)
A thyme plant will need at least 4-6 inches of soil to accommodate its root system, which generally stretches to a modest 6 inches.
When planting an already established thyme plant in a pot at home, make sure that your soil mix covers the entire root system. You can place the plant slightly deeper to promote more root growth.
As previously mentioned, thyme is an herb that prefers somewhat dryer growing conditions. This is a plus for the grower, requiring less frequent watering sessions and making it an ideal windowsill plant.
How Much Water Does Thyme Need?
Thyme is a drought-tolerant herb that can survive with minimal water, but it does prefer well-draining soil and regular watering to keep the soil evenly moist.
Generally, it's a good idea to water thyme plants when the top inch or so of soil feels dry to the touch. Be careful not to over-water thyme, as it can be prone to root rot if it sits in soggy soil for too long - better to water it with less water than to overwater it.
It's also a good idea to allow the soil to dry out slightly between waterings to prevent the development of fungal diseases.
How Often Does Thyme Need Water?
You may be pleased to know that you don’t need to water your indoor thyme plant on a weekly basis. Ideally, you should water it once every 10-15 days to prevent the possibility of root rot, mold, plant yellowing, and wilting.
If you lose track of the last time you watered the plant, a good rule of thumb is to insert your fingertip into the top ½-inch of soil. If you feel even slight dampness, then the thyme has sufficient moisture. If this soil area feels dried out, it’s time to water the thyme plant again.
Sunlight is essential in the photosynthesis process for nearly every plant. When it comes to thyme, adequate sunlight is especially important, as this factor determines the plant's color, strength, and health.
Without enough sun, your indoor thyme plant may not naturally dry as it should, and you might even experience legginess (a lack of leaf growth). This is why direct, natural light coming from a windowsill is probably the best way to nurture your thyme plant.
How Many Hours of Sun Does Thyme Need?
In general, an indoor thyme plant should be getting at least 6 hours of direct sun each day. If you can achieve more, that’s even better. This is why a windowsill that’s shaded by a treeline is not a great spot for a thyme plant.
Does Thyme Need Full or Partial Sun?
Thyme needs full sun to thrive, partly owing to the herb’s Mediterranean origins. Where this plant comes from, the weather is notoriously sunny, warm, and dry.
If you can’t achieve full sun in your home, you may need to supplement some light with a grow light. These devices mimic the sun's light spectrum to provide adequate fuel for a plant’s photosynthesis.
Temperature Conditions for Indoor Thyme
Lucky for indoor thyme growers, maintaining a constant, balanced temperature within your home shouldn’t be too difficult.
Thermostats make this aspect of growing the herb much more practical than it would be if you were growing it in your backyard garden.
The ideal temperature for an indoor thyme plant is about 70°F (21°C). However, keeping it within the general range of 65-80°F (~18-27°C) will often suffice just as well.
Thyme needs a fairly warm environment in which to grow. For this reason, keeping your plant pot in or near a window that is not well insulated, especially during the colder winter months of the year, is not recommended.
If you need to keep your household cooler for whatever reason, you can always make use of a plant grow light to supplement some much-needed heat for your indoor thyme plant.
Fertilization Needs for Indoor Thyme
Thyme is one of those indoor plants that require a surprisingly low amount of nutrients in its soil to grow well. In fact, some gardeners feel that this plant actually doesn’t need any further fertilization if you use the right soil mixture.
However, in some cases, your thyme plant may suffer, or you simply find that it grows better when it receives a regular dose of fertilizer.
Some of the options for this particular herb include the following:
- An all-purpose 10-10-10 (NPK) indoor plant fertilizer, only required once during the growing season
- Organic matter, such as a compost mixture once or twice a year
- Liquid seaweed fertilizer is to be applied once in the growing season
- Dilute fish emulsion fertilizer to be applied to the soil once in the growing season
Can I Skip Fertilization?
If you feel that your indoor thyme plant is thriving under the conditions you maintain - adequate sun, water, heat, etc. - then you may not need to add more fertilizer.
Like lavender, thyme is a fairly hardy plant that makes good use of a high-quality soil mixture.
How to Prune Indoor Thyme
One aspect of indoor herb gardening that many people overlook is the process of trimming and pruning. While it’s nothing like the process needed for bonsai, for example, pruning thyme can positively affect the health of the plant and lead to a greater harvest when that time comes.
When pruning your indoor plant, make sure always to use a sharpened, sanitized shear or some other similar tool. Keeping the tools clean ensures that you aren’t spreading outside bacteria or substances to your thyme plant, leaving it vulnerable to disease and downfall.
How to Prune
Once you’ve acquired the right tools, take the following pruning steps:
- Watch for signs of thyme growth and flowering,
- Once the plant blooms, begin by trimming back some of the stems with a clean cut just above the leaves that will become the top of the stem,
- Dispose of the cuttings or set them aside to propagate new plants,
- Make sure not to prune more than ⅓ of the thyme plant.
When you successfully prune your herbs, they are more likely to grow back even fuller than they were before. This positive step is important for an indoor plant so that you can get multiple harvests from it and avoid the transformation to a woody plant.
How to Harvest Indoor Thyme
The last and possibly most rewarding step of growing thyme indoors is harvesting the herb. Thyme can be used fresh or dried.
The average time frame from seed to harvest for thyme is about 75-90 days. However, if you’ve started with an established plant or seedling, as most indoor gardeners do, you will get to harvest the herb much sooner.
Examine the plant to determine whether your thyme is ready to harvest. If the buds look like they are just about to open and flower, then it’s time to harvest. You can also examine the leaves of the plant to determine the harvest. You should be able to trim roughly 8-10 inches at once and leave behind a decent amount of the stem below.
Make sure you only harvest thyme before it has blossomed for the best taste. Furthermore, you want to select the younger, greener, and more tender parts of the stems rather than the woodier growth.
How to Harvest
The process of actually harvesting the thyme is fairly simple and quite similar to the process of pruning. Sometimes in the pruning process, you may even keep some of the cuttings as a partial harvest.
- Start by selecting clean, sharp shears to harvest with,
- Cut off the stems that are ready to harvest, just above the closest leaf pairing,
- Try not to cut off more than ⅓ of the plant unless this is your final harvest of the growing season.
Once you’ve cut away your thyme harvest, make sure to rinse it to remove bacteria and dirt thoroughly. Then, store it in a damp paper towel inside an aerated plastic bag. This can be kept fresh in a refrigerator for up to 2 weeks.
Also, thyme can be easily dried and used in various meals and recipes.
Few Final Thoughts
If you’ve ever wondered how to grow thyme indoors and enjoy the benefits of a windowsill herb, hopefully, our guide has pointed you in the right direction. Thyme is one of the easier and lower-maintenance herbs to grow indoors, as it requires very little watering and fertilization.
Make sure to give a thyme plant full sun in a 65-80 degree F location, with well-draining soil and plant pot. By following the right maintenance rules, you can get multiple harvests out of your indoor thyme plant in no time.