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Small Greenhouse for Winter: Do Greenhouses Stay Warm in Winter? 

Do you want a small greenhouse for winter? Here is a guide on how to keep your plants warm during the winter months.

Usually, greenhouses are used to extend the growing season of plants. But do they also work to keep the plants warm during cold months?

Although uncommon, you can use greenhouses to keep plants warm in winter. However, some things must be considered if you want your greenhouse to do the job.

So, if you are trying to determine whether greenhouses stay warm in winter, the answer is yes. And they can keep your plants warm if you know how to follow some important steps or techniques.

In this blog post, we will discuss how you can make this happen and keep your plants safe during cold winter nights and days. So, whether you want a small greenhouse for winter gardening or a big one for an all-season cycle, this piece is for you.

Read on!

What is a Greenhouse?

plants and flower pot placed on the table in greenhouse

What is a Greenhouse?

A greenhouse is an enclosure with transparent walls and roofing to create a controlled environment suitable for plants. It traps the warmth from the sunlight to keep the plants inside warm without being affected by the harsh sun rays. It also helps protect the plants against the wind, rain, and other elements that can damage or destroy your plants in cold weather.

During winter, many people find it challenging to keep their plants warm. This is because the temperature outside can drop drastically, leaving your plants vulnerable to frost or even death. That’s where greenhouses come in handy. They offer a controlled environment, ensuring plants thrive even in the coldest weather.

However, there are some things you should do to ensure that your plants are protected. One, ensure that the greenhouse is well insulated. Second, ensure the greenhouse is dry at all times.

Lastly, you should ensure that the heaters are in good shape and that you have enough fans to get the warm air to every corner of the greenhouse. With that, you can enjoy your winter gardening with minimal worries.

The Popularity of a Greenhouse

Today, a greenhouse is popular in botanic gardens, resorts, botanical institutes, and places classified as having tropical or therapeutic environments. It also functions as an enclosed space to produce plants for special purposes, such as heated crops during winter months or high-value herbal crops for medicinal purposes.

Greenhouses can be used to encourage the faster growth of plants. For instance, they help add the amount of CO2 available for the plants by heating the air circulating through the plant beds. Adding more water vapor into it through fogging systems is also easier.

These actions help tender plants grow larger and require less frequent watering from the greenhouse operator. As such, more people are finding greenhouses useful. They are using them for protecting plants against harsh weather and a fast way of growing plants.

What is the Main Purpose of a Greenhouse?

greenhouse in a glass wall

The purpose of greenhouses is to offer protection for your favorite plant against climate change. It helps keep the plants warm and protected from harsh weather conditions like wind, rain, snow, and extreme temperatures.

Greenhouses also help you extend the growing season for your plants as they trap and retain heat that enters the enclosure. This provides stable temperatures for your plants all year round.

That said, greenhouses can also be used to keep plants warm in winter. By ensuring that your greenhouse is well insulated and has enough heating elements, you can keep your plants safe even in the coldest weather conditions.

However, check your greenhouse’s soil temperature and thermal mass. This ensures that it is ready to provide better protection for your plants.

See Related: Best Greenhouse Floors to Buy Today

What can a Greenhouse do for a Plant?

A greenhouse helps plants grow faster and healthier by increasing their growth rate, improving the yield, and leveling up the quality of harvested produce in colder or warmer climates. Other than that, a greenhouse helps in;

  • Automatically watering the plants
  • Fertilizing the plants
  • Providing better protection against pests and diseases
  • Offering water temperatures for the plants
  • Allowing you to grow vegetables or different varieties of crops all year round
  • Ensuring healthy root growth and improved yield

Ultimately, a greenhouse is one of the best investments that you can make for your garden or farm. It helps maintain the right environment for your plants, so they thrive and produce high-quality results. All these benefits combine to make a greenhouse an ideal choice for experienced and novice gardeners.

See Related: Best Glass Greenhouses in 2023

What is a good Temperature for a Greenhouse?

Hot water heating greenhouse

According to the UST criteria, the minimum temperatures in a greenhouse or hothouse should be at least 50 degrees Fahrenheit. Also, you must not allow greenhouses to heat up to 90 degrees Fahrenheit. This can be dangerous for your entire botanical collection.

The maximum temperature should be around 85 degrees Fahrenheit. This range ensures that your plants don’t get damp or damaged by too much heat.

You should also pay attention to humidity levels, as too much moisture can damage your plants. Your plants can thrive in their greenhouse environment with the right temperature and humidity levels.

See Related: Best Energy Efficient Electric Heaters for Large Rooms

How do you Control Greenhouse Temperatures?

Heating a greenhouse in winter is important to ensure that your plants are protected from extreme temperatures. Here are some of the things you can do to keep your greenhouse warm:

  • Insulate Your Greenhouse: Ensure your greenhouse’s walls, floors, and ceilings are properly insulated to retain heat during cold winter. You can use either a traditional bubble wrap or a UV-stabilized horticultural one.
  • Install a greenhouse heater: You can install heaters to keep the temperature in your greenhouse warm enough for your plants to survive. A great option here includes the space heaters, but you can also try a ground source heat pump.
  • Use Thermal Blankets: Opt for thermal blankets if you don’t want to install outdoor heaters. These will provide a layer of insulation to keep the heat in your greenhouse during cooler temperatures.
  • Add thermal mass: Thermal mass is the ability of a material to absorb and store heat. Filling your greenhouse with materials like stone or water tanks can help absorb heat during warmer days and release it during cold winter nights.
  • Composting: Composting is an excellent way to naturally heat your entire greenhouse. The compost will generate heat as it breaks down, creating an ideal environment for plants.
  • Ventilation: Ensure proper ventilation in your greenhouse to keep the air circulating and prevent mold from building up.

See RelatedBest Green House Plastic Covering

Setting up a Greenhouse

A garden greenhouse

Image source: Pixabay

Setting up a greenhouse can be daunting, but it doesn’t have to be for you. Here are some tips to help you get the job done quickly and adequately:

  • Choose the Right Location: Pick a spot where your plants will get enough sunlight throughout the day. Make sure there is plenty of room for air circulation, and ensure the area is level and free of obstructions.
  • Measure the Area: Get accurate measurements of where you will be setting up your greenhouse to ensure you purchase the correct size materials.
  • Assemble Your Greenhouse: Follow the instructions provided by the manufacturer carefully to assemble your greenhouse properly.
  • Install Heating and Insulation: Ensure that your heating and insulation are installed properly to maintain an ideal temperature for your plants all year round.
  • Protect From Pests: Ensure you install pest control measures, such as screens or traps, to keep out pests that may damage your plants.

What do you do with a Greenhouse when the Weather Changes?

Greenhouses for winter

When the weather starts to get cold, most people choose not to do anything with their greenhouses. If it’s going to be cold for a short period, your plants will be fine inside it.

However, if it looks like the cold weather will stick around for some time, you need to take extra steps. You need to ensure that your greenhouse stays warm during the cold temperatures.

This can be done by increasing the amount of insulation and heaters inside the greenhouse and using thermal blankets to help keep the temperature steady. Additionally, you need to pay attention to humidity levels so that your plants don’t suffer from too much moisture. With these steps, you can ensure your plants stay healthy even during the cold weather.

What do you do with a Greenhouse when it Starts to get Cold?

When the weather turns warmer, you must take steps to prevent your greenhouse from getting too hot. This can be done by increasing ventilation and using shading techniques such as installing shade cloths or using reflective surfaces like aluminum foil. You may also need to adjust the insulation to maintain a comfortable temperature.

Additionally, you must be vigilant about pest control during the warmer months. Insects and rodents can wreak havoc in a greenhouse, so ensure you take the necessary steps to prevent them from getting inside.

When does a Greenhouse Stop Working?

Small greenhouse for winter; green seedlings on a growing bed

Image source: Pixabay

A greenhouse will stop working when it can no longer maintain a comfortable temperature for your plants. This could be caused by a lack of insulation, excessive heat or cold temperatures, or pest infestations.

When one of these problems arises, you must address the issue before it causes long-term damage to your plants. For instance, if the temperatures fall too low, you need to install heaters or add insulation. On the other hand, additional ventilation or shading will be necessary if there’s excess heat.

The winter protection techniques that keep an unheated greenhouse warm in winter will not be effective if the days are cloudy. This is because the greenhouse does not get enough sunlight or warmth on days when the temperature is nearly freezing. And that’s why you’ll need the extra heating.

If the problem is severe enough, it could be necessary to dismantle and rebuild the greenhouse to get it working again. Remember, the goal is to provide the most comfortable environment for your plants.

What Happens if your Greenhouse is Damaged?

The important thing to do when your greenhouse is damaged is to repair it as soon as possible. The longer it takes, the harder it will be for your botanical collection to recover.

If your greenhouse is flexible, try removing snow from its roof before assessing whether it can be repaired or needs replacing entirely. If your greenhouse is made out of plastic, do not try to clear off snow with a shovel or broom. Doing this will do more damage than good because the roof will likely break apart at the seams.

Instead, grab a dull tool like an ice scraper and lightly go over it until all the snow has been removed. If your greenhouse cannot be repaired, do nothing to the plants. They can survive a bit of cold weather because they are covered in snow.

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Different plants growing inside a greenhouse

The truth is you don’t need to heat your greenhouse during the winter. However, if the greenhouse has insufficient insulation or is too chilly for whatever reason, you should take measures now to keep it warm throughout the next several months of winter. This ensures that your plants are not harmed.

Greenhouses do not stop working during winter unless something happens. If they do, be sure to act fast. And if you want to learn more about garden tips, sign up for our newsletter.


How can I heat my greenhouse for free in the winter?

Sometimes people try to heat their greenhouses with an electric heater, but this idea is not always ideal. A greenhouse acts as a gigantic convection oven.
Instead of heating it from the inside, you are better off insulating the outside walls with styrofoam panels or buying solar PV panels. This way, you can harness solar power to keep your greenhouse warm all winter.

How warm is an unheated greenhouse?

Warm enough to do some cool things, but you’ll need supplemental heating too. An unheated greenhouse works better in areas that don’t get negative temperatures in winter. However, if you experience extreme weather, getting an electric heater is better to keep tender plants alive.

Do greenhouses need a heater in winter?

While it is not a must, greenhouses can use additional heat from a heater during winter. This mainly ensures ample warmth for tender plants during severe cold temperatures. Adding a solar-powered heater can help keep heat energy costs low.

What is the lifespan of a greenhouse?

The average lifespan of a wooden greenhouse is between 45 to 60 years. On the other hand, a glass-made greenhouse can care for your plants for around 30-40 years. However, the lifespan of a glass greenhouse will depend on how well you take care of it, as glass is quite fragile.
For the new-tech polyethylene film or polycarbonate greenhouses, they can give you up to 5 years. These are considered a bit temporal, unlike the previous two options.

What size heater works best in my greenhouse?

It’s crucial to pick the right size heater for a greenhouse. And the first thing you need to do is learn the greenhouse’s square feet. Second, find out the difference in temperatures in your area.
Multiply the unheated greenhouse’s square feet by the temperature differences. The result you get, multiply it with the heat loss factor to learn the right size heater.

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