How Does Your Garden Grow?

Minimizing damage to plants in freezing temperatures

By Katherine Clarkson
Posted 9/25/20

When you live in Wyoming, you become accustomed to swings in temperature. However, our plants do not adjust as well. A drop in temperature will cause photosynthesis (food production) and respiration …

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How Does Your Garden Grow?

Minimizing damage to plants in freezing temperatures

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When you live in Wyoming, you become accustomed to swings in temperature. However, our plants do not adjust as well. A drop in temperature will cause photosynthesis (food production) and respiration (food utilization) to slow down, which results in the plant’s growth to stop and in some cases to die.

To better understand the outcomes of low temperature, we will explore how it affects different parts of the plant, what happens to the structure of the plant, and ways to minimize damage.

Parts of a plant will react differently to temperature fluctuations. With a fruiting plant, the temperature of the fruit is like that of the air. As the air temperature drops, the temperature of the fruit will drop. Yet, the fruit temperature will change slower than the air temperature.

The temperature of flowers is typically higher than the air and even the temperature of the leaf. The top of the canopy will have greater fluctuations than the bottom. Also, seedling and young plants are much more sensitive to the cold than plants that are 2 years or older. Moving forward, let us inspect how the structure of the plant is affected.

When plants are exposed to 32 degrees Fahrenheit (0 degrees Celsius), ice crystals form inside their cells. As these ice crystals expand, they attract water from the organism which results in dehydrating cells and rupturing a plant’s membrane. Once these cells are frozen, it renders it inaccessible for photosynthesis. After this physical damage has occurred, it will manifest itself as a brown to yellow necrosis. In addition, water that freezes the surrounding soil causes desiccation, which in turn decreases the amount of water it can receive. While you can’t control the weather, with a little effort you can protect your plants from the wintry weather.

To strengthen young plants, an important step is to protect them as soon as you plant them. This process is called hardening, and it is an essential step as it builds their tolerance and resilience to the new temperature. The following link will guide you with step-by-step directions on hardening a plant: bit.ly/304E3pB.

It is also important to choose hardy or native plants for our zone. Native plants are species that are naturally found in your climate. As much as I would love to grow orchids outside in Wyoming, I must accept that will not happen. They simply are not native and cannot handle the temperature of our zone. If you are interested in which plants are native, refer to the UW Extension publication titled “Plants with Altitude Regionally Native Plants for Wyoming Gardens,” which can be found at bit.ly/2ZNuJWQ.

Also, be careful removing snow or ice from plants. Most of the time, it is best to leave the snow-covered plant thaw on its own. Know when the first and last frost of the season will occur. I rely on the Farmer’s Almanac. It has been time tested and generations approved.

Keep your plants healthy. A healthy plant will withstand the stress of cold, however not freezing temperatures. Treat your plants in the fall with a fall fertilizer. September is the best time to apply a low-release formula which is designed for the long haul. It supplies nutrients gradually without burning the roots. A fertilizer with a formula of 20-8-8 will work well. After applying your fertilizer, you will want to water the plant before you blow your irrigation system out.

Within preferred temperature limits, each plant has a unique ability to respond to the amount of temperature change that occurs. All you can do is stay aware of weather conditions and try to protect plants the best you can. But remember, no matter how well you plan, Mother Nature is in charge. Thank you for reading and if you have any suggestions, questions or comments, please contact me at katherineclarkson2@gmail.com.

 

(Katherine Clarkson is the president of the Park County Master Gardeners. She lives in Wapiti.)

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