Can Thyme Survive Winter? [Full Guide]

Thyme is a Mediterranean herb that is commonly used in homes for cooking. It can be found in all kinds of dishes including European, Mediterranean, Latin, Central American, British, African, and Caribbean styles.

It’s a fairly easy plant to grow which is why so many people choose to grow it in their gardens. After all, why waste money at the grocery store every week when you can grow your own herbs? Maybe that’s why you’re here.

Have you decided that you want to grow thyme in your garden, but you aren’t sure if it’ll survive? Maybe you live somewhere that gets very cold over winter and are afraid the frost will kill off your plants.

Well, you’re in the right place. We’re going to cover how tolerant thyme is of the cold and what you can do to help it make it to the next spring.

Plant Hardiness Zones

Will thyme survive winter? If you live in hardiness zones 5-9, the answer is yes.

Thyme is a fairly cold-tolerant plant. In fact, it is considered a semi-evergreen plant and is capable of retaining some of its foliage even throughout the winter months.

In the cold United States winters, thyme is known for surviving in USDA hardiness zones 5 through 9. It can sometimes survive in zone 4 when it is provided with extra protection.

Can Thyme Survive Winter?

As I stated above, thyme is a very cold tolerant plant. It can survive in temperatures down to -20 degrees Fahrenheit. Some species can even survive down to -30 degrees Fahrenheit.

As long as you take care of thyme throughout the warmer months of the year, it should do just fine through the winter months. That is, as long as you live in zones 5-9. If you live in zones below 5, you’ll want to bring your thyme inside over winter.

Even though thyme is cold tolerant, there are things you can do to prepare it for the coming cold. Keeping your plant watered, pruned, and covered in mulch is most important in overwintering your plant.

Thyme in winter
Thyme in winter

What Is The Lowest Temperature That Thyme Can Survive?

The lowest temperatures that culinary or English thyme can survive is down to -30 degrees Fahrenheit. These varieties are the exception to the rule though, because they can survive in zone 4.

Most thyme varieties, like lemon thyme and creeping thyme, can only survive down to -20 degrees Fahrenheit. They can survive in zones 5 and above.

Still, -20 degrees Fahrenheit is extremely cold, so it’s impressive that thyme can survive these extreme temperatures and even produce foliage. It’s safe to say, then, that thyme will survive through winter unless you live where the winter becomes extremely harsh.

Should You Bring Thyme Inside In Winter?

Unless you live in hardiness zones less than 5, it’s not necessary to bring your thyme inside over winter.

However, if your thyme is outside, but is kept in a pot, you should bring it inside over winter. Being in a pot leaves a plant’s roots more vulnerable to the cold and frost. To protect your potted thyme from the cold, it’s best to bring it inside.

There is always the option to keep your thyme inside permanently as well. Thyme prefers warm whether and lots of sun. If you’re able to provide that for your thyme year-round, your plant will grow well during any season.

If you do choose to bring your thyme inside over winter, there are some things you can do to keep it thriving.

Keeping Your Thyme Plant Inside

Light

Thyme loves lots of light. The best place to keep your thyme inside is next to a window that faces north. However, if you don’t have a window available, the plant can survive under indirect light as well.

Water

Thyme shouldn’t be overwatered, and it’s especially important not to water it too much while inside. Only water thyme when you feel that the top inch of soil has become dry.

Fertilizer

Fertilizer usually isn’t necessary either. But, if you want to give your plant an extra bit of nutrition, you can use quarter-strength fertilizer no more than 2 times over the winter.

Hardening Off

You can take thyme back outside after the last threat of frost has passed. However, your thyme has grown accustomed to the indoor climate of your house. Because of this, it really should be hardened off before you replant it permanently outside.

Hardening off simply refers to the process of preparing your thyme from going inside to being outside.

To harden of your thyme, you’re going to place your pot of thyme outside in a location that is shaded and protected. This is usually a place like a porch. You’ll leave the pot outside for a few hours before bringing it back inside.

You’ll repeat this process for a few days. Each day, you’ll gradually increase the amount of time that your thyme is staying on the porch. Never leave your thyme outside overnight. This whole process will take between 3 days and a week.

Once your thyme has spent a full day outside in the protected area, it’s ready for more light. Repeat the above process, but use an area of your yard that is in full sunlight. Once this is completed, your thyme is ready to be moved back into your garden.

How To Protect Thyme Over Winter

Fortunately, thyme is a very cold tolerant plant, so it doesn’t need much protection. Still, it’s good practice to cover the roots with a bit of mulch to protect it from the winter cold.

I especially recommend this if you live in hardiness zone 4 and 5 as the frigid temperatures can be quite harsh on your thyme.

Mulching

When the temperatures start to drop, you’ll want to add 2-3 inches of mulch overtop of your thyme’s roots. This will keep the soil warm and protect the roots from frost.

For this same reason, you won’t want to apply mulch before the air becomes cold. Adding mulch too soon can heat up the soil too much and make your plants less cold tolerant.

To time this right, you’ll want to apply the mulch during a period of extended cold. This will keep the soil warm while also preventing the soil temperatures from fluctuating.

How To Prepare Thyme For Winter

Although thyme is very adept at surviving through the winter months, there are still things you can do to help it out. The best thing you can do for your thyme plant over winter is making sure the soil has good drainage and that you cover the roots with mulch.

We’ve covered why mulching is important above, and now we’ll go over the importance of water.

Water

Thyme needs lots of water to be happy, so you shouldn’t starve it. One of the best ways to prepare your thyme for winter is to keep it hydrated before the cold months set in. Water your thyme adequately throughout the summer and fall months. That is one of the best things you can do to prepare your thyme for winter.

To add to that, make sure that your thyme is planted in well draining soil. Adequate watering doesn’t do any good if the thyme is planted in the wrong soil. Too much water in an ill-draining soil can cause the roots to rot on your thyme and the leaves to wilt.

If your thyme is planted in soil that doesn’t drain well, it likely won’t survive the winter. Water logged soil mixed with freezing temperatures doesn’t make a great combination.

Pruning

Avoid pruning your plant too much during the late summer and fall months. Yes, pruning keeps your plant healthy and will encourage new growth. However, this is best done in spring and early summer. Clipping your plant too close to the winter months will leave the exposed stems more vulnerable to frost.

Light harvesting is okay if you need the leaves for cooking, but heavy pruning should be saved for the earlier months.

Does Thyme Grow In Winter?

Growing thyme in winter can be a bit tricky. Thyme is considered a semi-evergreen plant and is cold tolerant. Semi-evergreen means that, while it doesn’t grow its best during winter, you are still likely to see a bit of new growth.

Unlike most herbs that die back and go dormant over the winter, thyme will continue to grow. It just does it a bit more slowly.

Final Words

Fortunately, thyme is a cold tolerant plant. Unless you live in the coldest parts of the United States, your thyme will be just fine throughout the winter months.

Still, you should keep your plant well watered and trimmed to prepare it for the coming cold. You should also be ready to cover it in mulch over winter, especially if you live in zones 4 or 5.

Now that I have eased your mind, it’s time to get planting.

Want to learn more? Find out how much sun thyme needs here, how to dry thyme here and how tall thyme grows here. You can also find all my guides to growing thyme here.