Is An Unheated Greenhouse Frost-Free Or Not

Is an unheated greenhouse frost-free? Indeed, a heated greenhouse is necessary. But what happens if you only have an unheated one? Well, you don’t have to worry about a single thing because an unheated greenhouse can be frost-free.

Disney’s Frozen once said, “Only an act of true love can thaw a frozen heart.” But do you know that keeping your plants healthy during winter takes more than just an act of true love?

Is An Unheated Greenhouse Frost-Free Or Not

This article will show you several techniques on how to keep your crops warm enough during the cold weather. Though they might look intimidating, these methods are easy to follow and also cost-effective.

Remember, an act of true love with passion and determination can thaw a frozen greenhouse. Let the storm rage on because, with these methods, the cold will never bother your crops.

Techniques On Heating Greenhouse

People often say, “As long as the sun is rising, there is hope.” And yes, as a fellow garden enthusiast, I am here to say that as long as the sun shines, there are a lot of techniques we can incorporate in keeping our plants warm enough.

Make sure your plants obtain an adequate amount of light. Eliminate any material that would prevent your plants from getting enough light and consider cleaning the glass to maximize available light.

If you’ve accomplished these things already, then let us proceed with the techniques. Below are some of the tips that you can utilize to keep your unheated greenhouse warm during winter.


#1 Outer Covering

Consider covering all parts of the unheated greenhouse with a single layer made of plastic to maximize the light input.

Although utilizing two layers of plastic and blowing air into the space between them guarantees more protection from cold, it prevents the greenhouse from acquiring an extra ten percent of possible light.

In addition to this, purchasing another layer of plastic and purchasing an electric blower to inflate the layers are costly.


#2 Double covers

In an experiment comparing an air-inflated greenhouse and an unheated one with only a single layer, garden enthusiasts have obtained a valuable conclusion.

In the experiment, the temperature data obtained show that night time low temperatures with a mean of 4˚ F (2.2˚ C) are warmer in the air-inflated house compared to the unheated house single-layer outer covering.

For instance, during the night, when the low temperature was –8˚ F (–22˚ C) outside, the temperature decreased to 20˚ F (–7˚ C) under the inner layer of row cover and 2˚ F (–17˚ C) inside a single-layer house.

In conclusion, the temperature in the air-inflated greenhouse was 7˚ F (–14˚ C). Meanwhile, under the row cover’s inner layer, it was 24˚ F (–4° C).

The observations made during the trial created some remarkable comparisons between the two houses.

Although there are no apparent differences in the quality of crops, the duration regarding the seedlings’ growth was faster in the air-inflated greenhouse. In addition to this, the air-inflated house also warmed quicker.

Therefore, double-covering the unheated greenhouses is advised because it speeds up the growth of the seedlings.


#3 Inner layer

There are a lot of options when it comes to inner layering. But we have to choose the best one. You can always make little tunnel greenhouses within larger ones; and yes, this method is still employed by some of our Japanese farmers.

However, we have to know our limits. Is placing tunnel greenhouses efficient in space? Are the methods of its ventilation and management easy?

The answer is no. How about motorizing the night-curtain systems? Although this method employed in reflective materials and is effective in greenhouses, we have to weigh our budget.

Doing this method is very costly. Then what should we do? Well, lucky for you, we have the simplest and most cost-effective option in store for you.

Allow me to present the most affordable choice- a floating row cover. Although the floating row covers are less protective against the cold than glass frames, it has a self-ventilating nature.


Crops To Plant During Winter

Is it possible to grow plants during winter? Well, I would like to quote what Audrey Hepburn once said, “Nothing is impossible.”

There are a lot of plants that you can grow during the winter season. Here are some of the following:

  • Garlic
  • Leeks
  • Onions
  • Radishes
  • Lettuce
  • Peas
  • Potatoes
  • Swiss chard and other greens



Is an unheated greenhouse frost-free? Are you worried about your plants not making it through the winter? Are you anxious that you might not be to grow plants because of the cold weather? Are you scared that your unheated greenhouse might not be frost-free?

Well, worry no more because we’ve got the best solution for you! The key? It’s layers.

Through this guide, you will be able to make your unheated greenhouse frost-free without even worrying about the expenses. The methods presented in this article are comprehensive and one hundred percent cost-effective.

Now prepare your layers because, for the first time in forever, you’re about to thaw a frozen greenhouse. Always remember, the plant that grows in adversity is the most beautiful and rare of all. Good luck and best wishes!

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