With the increase in self-sustaining gardens, herb patches are the new trend. Many garden owners dedicate areas to growing herbs used in medicine and cooking. However, maintaining a herb garden can be challenging in winter—since herbs cannot survive icy weather.
Generally, temperatures below 45-50°F (7-10°C) are too cold for outside herbs. Some herbs may survive 40°F (4°C), but most herbs need temperatures of at least 65-70°F (18-21°C) to survive. Ideally, you should keep your herbs in a room with nighttime temperatures of at least 55-60°F (12.8-15.6°C).
In the rest of this article, I’ll discuss why most herbs can’t survive cold weather and which ones can thrive in cold climates. I’ll discuss how to grow a healthy crop of herbs by maintaining the best conditions for soil, temperature, water, and sunlight. Let’s dive in!
Why Cold Weather Is Bad for Herbs
Cold winters commonly cause crop failure in many parts of the world. Plants usually depend on a certain amount of sunlight and warmth for growth. Hence, a cold, cloudy winter naturally results in the plants getting less nutrition.
Herbs are generally even more delicate than shrubs or trees. As a result, they’re even more particular about having the ideal weather conditions.
Here are some of the reasons why cold weather negatively affects herbs.
- Cold weather slows enzyme activity. Herbs use enzymes to break down nutrients for growth and production, so slow enzyme activity affects how the herbs grow.
- Temperatures below the water freezing point (32°F or 0°C) cause the water inside the cells to freeze. This reaction kills the plant by puncturing through the cell walls and causing leakages that kill the cells.
- Freezing temperatures can freeze the soil around the plant. The plant cannot absorb frozen water in the soil, leading to less absorption and retention.
- “Frost Heaving” is when the soil pushes plants up due to repeated freezing and thawing. This movement can break smaller roots and sometimes force the entire plant out of the soil.
- Fast winds lead to a higher rate of transpiration. In many cold places, particularly hilly areas, fast winds are just as dangerous as the temperature. These winds make plants lose water from the leaves faster than they can absorb it from the ground.
Can Herbs Be Left Outside in the Winter?
Herbs are usually very picky about the kind of weather conditions they require. Most herbs require warmer, humid climates with decent air circulation but not too much wind. These conditions can be challenging to maintain.
Herbs should not be left outside in the winter because they will not survive the cold. You can leave your herbs outside if you live in a warm, tropical climate with relatively warm winters. However, if the temperature goes below 60°F (15.6°C)—you should bring your herbs inside.
If you’ve got herbs planted in your garden, you should find out what temperatures they can survive and decide accordingly. If you live in a place where even winters are relatively warm, you may be able to leave your herbs outside without worrying. However, if you regularly get colder, windy weather during winter, you should bring your herbs inside.
Optimal Conditions for Growing Herbs
Since herbs require a delicate balance of air circulation, humidity, sunlight, and soil quality, let’s look at the optimal conditions for growing herbs.
Maintain Adequate Temperatures for Your Herbs
Herbs generally need daytime temperatures of at least 65-70°F (18-21°C) and nighttime temperatures of 55-60°F (12.8-15.6°C) to survive. Some herbs might require more or less than this, so you’ll need to check what your herbs require.
Here are the average temperatures necessary for some of the most common herbs.
|List of Common Herbs||Average Temperature|
Note: The temperatures mentioned above are approximate numbers.
Ensure There’s Proper Sunlight (at Least 4–6 Hours)
Some herbs can manage with less sunlight, but most require a lot. For example, some herbs like basil, rosemary, and sage require a full day’s sunlight (6-8 hours). Others can manage with approximately 4 hours of sunlight, but any less than that may stunt the growth of your herbs.
If you’re leaving your herbs outside, ensure they have enough sunlight, even in winter. It would be best if you provide some light shade—to prevent them from becoming too warm (especially if you live in warmer places). If you keep your herbs indoors, try to place them near a sun-facing window. Rotate the containers regularly to ensure that all sides of the plant get enough sunlight.
Use Well-Draining, Rich, and Moist Soil
Most herbs can grow in regular garden soil. The best soil is rich in organic material, well-draining, and moist. Herbs also require little supervision, so they’re perfect for beginner gardeners.
However, some herbs may be invasive, so it’s best to keep some containers nearby instead of planting them directly into the soil. If you would like to know which herbs are prone to spreading invasively, check out my article: Are All Herbs Considered Invasive?
Don’t Overwater Herbs and Keep Them in Humid Places
Herbs need a relatively humid climate for adequate water absorption. However, this also means you shouldn’t overwater your herbs.
Herbs generally require a good balance between humidity and air circulation, so you can leave your herbs there if those conditions are present in your outside garden. If not, it may be better to keep them inside the house.
When watering your herbs, instead of sticking to a strict schedule, it’s better to wait for signs of drying out from your herbs. According to The Spruce, basil is an excellent indicator of lack of water since its leaves visibly droop when they become dry.
In general, if you live in a humid climate, you should only water your herbs at the roots once a week. Occasionally, you can lightly shower the leaves to get rid of dust.
Which Herbs Grow Well in Cold Weather?
Most commonly used herbs originated in Mediterranean climates, so they don’t do very well in cold weather. However, some popular herbs are capable of withstanding relatively cold weather.
Most of these herbs are perennial, which means they become dormant in the winter and then bloom again during spring. So they might not be fresh in winter, but they will grow again in spring. Meanwhile, if you need herbs during the winter, you can dry and store your herbs to use until the plants bloom again.
To learn more about this process, check out my article: This is Why Herbs Are Hung Upside Down
Here are some commonly used herbs that can withstand colder temperatures.
Mint is one of those highly resilient herbs—that flourish under extreme weather. Mints generally go dormant during the winter, but since they’re perennial herbs, they come back during spring.
Mints are known for being extremely quick to spread. Since they take very little time to cover large patches of land, they’re great for places where warm weather doesn’t last very long.
Chives are also pretty resilient perennial herbs, and like mint, they go dormant during the winter and bloom again during spring. If you want to learn more about chives, check out my article: How To Prepare Chives for the Winter
If you live in icy weather (below 40°F or 4°C), you can keep your chives indoors in pots and put them back in the garden once winter gets over.
Sage is another cold-hardy herb, growing well in colder weather. People often use this plant in herbal remedies for coughs, colds, and other illnesses, so it’s a popular choice for an herb garden.
The only thing to remember for sage is that the soil should be well-draining because too much moisture can cause root rot. So if frequent showers or snow is a problem in your area, you should keep your sage inside the house.
Most herbs cannot survive temperatures below 40-50°F (4-10°C), so it’s best to keep them indoors. You can leave them outside during the winter under the following conditions:
- The weather doesn’t go below 50°F (10°C) at night.
- There’s enough sunlight for the herbs.
- There isn’t a lot of frost or snow.
- There isn’t a lot of wind outside.
Otherwise, it’s best to keep them indoors and monitor the sunlight and moisture they get. While some cold-hardy herbs can be left out during winter, they generally go dormant and bloom during spring.