Thyme (Thymus vulgaris) makes an attractive windowsill herb. It can be tricky to grow indoors, but with the right care it can be very successful. This post has all the details on how to grow thyme indoors, including watering, positioning, pruning and more.
Thyme is a wonderful herb to grow. Being a Mediterranean herb, it is perfect for many types of western cuisine, and grows well in a temperate to sub-tropical climate.
However, because of this origin, it is sensitive to frosts and prefers drier conditions. This means it may not overwinter well outdoors if you live in a cold climate. A solution to this is to grow your thyme indoors!
Growing thyme indoors
Grow thyme from seed
Thyme is very easy to grow from seed, You can expect it to take around 10-12 weeks from sprouting until you have a mature thyme plant. For all the details check out this post: How to Grow Thyme from Seed.
Grow thyme from cuttings
Probably the easiest way to grow thyme is to regrow it from some cuttings for another plant. This is a straight-forward process, and can be done with or without the use of a rooting hormone. Check out this post for more details: Growing Thyme From Cuttings.
Dividing or repotting thyme
You can also propagate thyme by dividing an existing plant. If it is time to repot a thyme plant, you can easily divide it into two or more plants.
Always use a good quality potting mix for growing herbs in pots. Choose one that includes sand for improved drainage if possible.
Select a pot with good drainage, look for something with multiple holes in the bottom, and remember to place it in a saucer or outer pot without holes.
Once established, thyme will grow and propagate itself to fill the pot, so choose a pot that will give your thyme room to grow, and be prepared to repot it when needed (more info below).
Potted Thyme Care
Thyme prefers a sunny position indoors with lots of bright light, and direct light is best. However, it can also thrive in indirect light as long as it is still in a bright spot.
So choose the right location depending on the climate where you live. Try placing it in or near a south-facing window so it will receive 6 or more hours of sun per day. You can also grow thyme under fluorescent lights, however, it will need 14+ hours of this type of light per day.
If you prefer, you can move thyme outside during the summer months. Wait until the temperature is consistently warmer overnight (and there is no chance of a frost). Then choose a location where it will get good sunlight and let it bask.
Watering and feeding
Being from a dry climate originally, thyme drought resistant, only requiring water when the soil has completely dried out. You need to take care not to over-water it as it is prone to root rot if over watered.
Only water thyme when the surface of the soil feels dry. Stick your finger in the soil to a depth of around ½ an inch, and if the soil is dry, give it a small amount of water. Remember to check frequently over the summer months or if the plant is sitting in direct sunlight.
If it is growing in well-draining potting media and a pot with drainage holes, it shouldn’t end up water logged. However, once you have watered it, ensure that there is no water pooling in the bottom of the pot. If there is, take it out of the saucer or decorative pot, and allow any remaining extra water to drain out of the inner pot drainage holes before placing it back in its saucer or decorative pot.
Thyme plants should be fed every two weeks with a diluted liquid fertilizer. Liquid seaweed is a good choice.
Pruning and harvesting thyme
Harvest the herb as needed once it is mature. Cut sprigs of thyme, making a cut directly above a leaf pair. Try to leave two or more leaf pairs on a stem to allow it to continue growing after the top part has been harvested.
Prune the plant to cut back any woody stems as it grows larger. This encourages more new growth, and helps the plant to stay compact as it grows.
Remove flowers as they appear to encourage the plant to continue to produce leaves.
A great way to preserve thyme leaves once you have cuttings after pruning the plant is by drying. It is a simple process for this herb, since it has soft leaves it can easily be air-dried. See this post for all the details on how to dry thyme.
Your thyme will probably need to be repotted at least annually. It is time to repot thyme when the roots start growing out of the bottom of the pot it is in. If you want to keep a small plant, you can divide it, repotting half or a third back into the pot it was in, and repotting the rest into another pot. Alternatively, choose a larger pot, but remember it will grow to fill the pot, so dividing is probably a better choice if you want to keep a small plant indoors.
If you notice the stem of your thyme is turning black, this is a good sign that the plant is suffering from water-stress, either too much, or not enough.
It can be very difficult to get the balance of watering right for thyme, and if you have been watering it regularly, then there is a good chance that it has developed root rot.
Whether it is possible to revive a thyme plant suffering from root rot will depend on how far the plant has become affected.
Carefully take the plant out of its pot and cut away any of the rotted roots and affected stems (these will have turned black).
Remove as much of the soil as you can and repot the plant with fresh potting soil. If the soil is completely dry, give it a small amount of water.