Is 40 degrees too cold for rosemary?

Answered by Michael Wilson

Rosemary is a hardy herb that is well-suited to Mediterranean climates. It thrives in bright, hot sun and sandy, well-draining soils. In terms of temperature, rosemary prefers warmer conditions and can tolerate temperatures as low as 30 degrees Fahrenheit. However, when it comes to the winter months, rosemary tends to prefer cooler temperatures during the day and slightly warmer temperatures at night.

During the winter, rosemary plants typically prefer daytime temperatures of around 60 to 65 degrees Fahrenheit. This range provides a balance between coolness and warmth, allowing the plant to remain healthy and vibrant. Cooler temperatures during the day help prevent the plant from becoming too stressed or overheated, while still providing enough warmth for it to thrive.

At night, rosemary plants prefer slightly cooler temperatures of around 40 to 50 degrees Fahrenheit. This cooler nighttime temperature helps mimic the natural conditions of the Mediterranean region and allows the plant to enter a state of dormancy. This period of rest is essential for the plant’s overall health and helps promote optimal growth and development.

While rosemary can tolerate temperatures as low as 30 degrees Fahrenheit, it is important to note that prolonged exposure to extremely cold temperatures can be detrimental to the plant. Frost or freezing temperatures can damage the leaves and stems, leading to browning, wilting, and even death of the plant.

To protect rosemary during colder periods, it is advisable to provide some form of insulation. This can be achieved by placing a layer of mulch around the base of the plant to help retain heat in the soil. Additionally, covering the plant with a frost cloth or bringing potted rosemary indoors can provide further protection during periods of extreme cold.

In my personal experience, I have found that rosemary plants can withstand cooler temperatures quite well. I live in a region with mild winters, and my rosemary plants have consistently thrived even when temperatures drop to around 40 degrees Fahrenheit at night. However, it is important to monitor the weather conditions and take appropriate measures to protect the plants if freezing temperatures are expected.

While rosemary can tolerate temperatures as low as 30 degrees Fahrenheit, it prefers cooler temperatures in the range of 60 to 65 degrees during the day and 40 to 50 degrees at night. These conditions mimic the Mediterranean climate where rosemary thrives. However, it is important to protect rosemary from prolonged exposure to freezing temperatures to prevent damage to the plant.