When you think of a greenhouse garden, what kind of images come to your mind?
Probably lush green plants and sweet-smelling flowers? Or a lot of sunlight and heat trapped within? Although these visual scenes of a greenhouse garden are more likely to be seen in summer or spring, you can grow your fair share of plants and flowers in winter as well. However, you won’t get as much a visual experience and variety as in summer or spring.
Given the fact that some varieties of plants can grow in colder temperatures, can these plants freeze in a greenhouse in winter?
Well, the short answer is yes, plants can definitely freeze in a greenhouse if proper care and precautions are not taken. Constant exposure to temperatures below 25 degrees Fahrenheit for a prolonged period without any form of heating or winter garden care can cause the plants to freeze even in a greenhouse. Also, if proper precautions are not taken while ventilating the greenhouse on bright, sunny days, the incoming cold draft can freeze the plants.
Common Mistakes that can Cause Plants to Freeze in a Greenhouse
As seen above, there are some common reasons which can cause plants to freeze in a greenhouse in winter. In addition to this, there are a few common mistakes which must be avoided, otherwise, they can cause the plants to freeze as well.
If the soil where the plants are grown is kept damp and marshy while going into the night, it can cause the plants to freeze. The roots freeze first as they are more sensitive after which the entire plant freezes. Especially if the plant variety is not accustomed to growing in subzero temperatures.
Plants grown in pots have a greater tendency to freeze in winter, especially the roots. Hence, care must be taken that unless you provide sufficient insulation to potted plants, they should be grown outside the pots.
Peat moss helps in enriching the soil with extra nutrients for the plants. So usually, the soil and the plants are covered in peat moss. Now peat moss thrives in winter cold temperatures and can absorb a lot of water. This water can freeze, thereby freezing the plants as well.
When you’re ventilating the greenhouse, it is possible that the cold air that is let in during the day can fall directly on the plants. Prolonged exposure to this subzero cold draft of air can also cause the plants to freeze. One way to prevent this is to make sure that the cold air is deflected away from falling directly on the plants.
Preventing the Plants from Freezing
Compared to growing plants and flowers in a normal garden, growing them in a greenhouse is much safer in winter. Yes, they can freeze when grown even in a greenhouse, but you can take measures to regulate the temperature and keep it above the freezing point.
And coming to think of it, that’s the whole purpose of a greenhouse. Providing conditions favorable to the growth of seasonal as well as non-seasonal plants all through the year. So plants than can grow in mild winters with temperatures above freezing point can still grow in areas with harsher conditions provided they are grown in a greenhouse with regulated conditions.
The whole concept of protecting the plants from freezing and passing over the winter is called overwintering of plants. While some plants can be protected by simply saving them from exposure to the open, other plants require certain other steps.
One way to prevent plants from freezing is by using a heater inside the greenhouse. In winter, on certain days, the sun can hide behind the clouds, and the greenhouse may not have natural heat to trap. In such cases, a heater can be of great help.
Roots and tubers can be brought inside and stored through the winter, and later grown back in the soil during spring. This is because the soil temperature can also go well below freezing point on really cold days.
There are many more ways how you can prevent the plants from freezing in winter. The detailed methods will be discussed in another post.
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