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How to Choose the Right Greenhouse Heater

How to Choose the Right Greenhouse Heater

A greenhouse heater is a device used to regulate the temperature inside a greenhouse. Greenhouses are designed to capture and retain heat from the sun, but during cold weather or at night, additional heating may be necessary to maintain optimal growing conditions for plants.

There are several types of greenhouse heaters available, including electric heaters, propane heaters, and kerosene heaters, as well as solid wood and pellet heaters.

Electric heaters are often preferred because they are relatively quiet, safe, and easy to use. Propane and kerosene heaters are also popular options, but they require more attention and must be properly ventilated to prevent the buildup of harmful gases.

When selecting a greenhouse heater, it’s important to consider the size of your greenhouse, the type of plants you are growing, and the climate in your area. You’ll also need to the cost of fuel or electricity and the heater’s energy efficiency.

It’s recommended to use a thermostat or temperature controller to ensure that your greenhouse remains at the desired temperature range. You can also use other methods to help regulate temperature, such as insulating your greenhouse, using a fan to circulate air, and opening windows or vents as needed.

Is it Safe to Put a Heater in a Greenhouse?

It can be safe to put a heater in a greenhouse, but it depends on several factors, such as the type of heater you use, the size of your greenhouse, the ventilation system, and the plants you are growing.

Heaters can be useful for maintaining a consistent temperature in a greenhouse, especially during cold weather or in areas with harsh winters. Make sure you pick a heater that is appropriate for the size of your greenhouse and doesn’t produce harmful fumes or emit excessive amounts of carbon dioxide.

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If you plan to use a heater in your greenhouse, make sure to follow the manufacturer’s instructions carefully and take steps to ensure proper ventilation to prevent the buildup of harmful gases. It’s also a good idea to monitor the temperature and humidity levels regularly to ensure that your plants are growing in optimal conditions.

What are the Most Common Types of Greenhouse Heaters

There are several types of greenhouse heaters commonly used for keeping plants warm in cold weather conditions.

Below are some of the most common types of greenhouse heaters.

Electric Heaters… These heaters are powered by electricity and are available in different sizes and styles. They are easy to use and do not produce any harmful emissions. However, they can be expensive to operate, especially if the greenhouse is large.

Propane Heaters… These heaters use propane gas as a fuel source and are ideal for larger greenhouses. They produce heat quickly and are cost-effective compared to electric heaters. However, they require regular maintenance, and the fuel can be expensive.

Natural Gas Heaters… These heaters are similar to propane heaters but use natural gas as a fuel source. They are also suitable for larger greenhouses and are cost-effective. However, they require a natural gas line, which can be expensive to install.

Wood-Burning Heaters… These heaters use wood as a fuel source and are an affordable option for smaller greenhouses. They produce a lot of heat and are environmentally friendly. However, they require a lot of work to maintain, and the emissions can be harmful to the environment.

Kerosene Heaters… These heaters use kerosene as a fuel source and are portable and easy to use. They are also relatively affordable. However, they can be dangerous if not used properly and produce harmful emissions.

The type of greenhouse heater you choose depends on the size of your greenhouse, your budget, and your environmental concerns. Electric heaters are easy to use and do not produce any harmful emissions but can be expensive to operate. Propane and natural gas heaters are suitable for larger greenhouses and are a cost-effective option. Check out Amazons line of greenhouse heaters here.

How Big of a Heater Do I need for My Greenhouse?

The size of the heater you need for your greenhouse will depend on a variety of factors, including the size of your greenhouse, the outside temperature, the desired temperature inside the greenhouse, the insulation of the greenhouse, and the types of plants you are growing.

As a general rule, you will need approximately 1 kW of heating capacity per 100 square feet of greenhouse space in order to maintain a temperature of around 70 degrees Fahrenheit in cold weather conditions. However, this is just a rough estimate, and you may need more or less depending on the factors mentioned above.

To get a more accurate estimate of the size of the heater you need, you should consult with a professional greenhouse heating expert or do some research on greenhouse heating calculators available online. It’s important to make sure that you choose a heater that is appropriate for the size of your greenhouse and will be able to maintain the desired temperature inside.


Is a Propane Heater Bad for a Greenhouse?

Propane heaters can be used in greenhouses, but they require proper installation and ventilation to prevent harmful effects on plants and humans.

They also release carbon dioxide and water vapor as by products of combustion, which can promote plant growth if properly managed. However, if the heater is not properly installed or ventilated, the accumulation of these by products can lead to problems such as excessive humidity, high carbon dioxide levels, and poor air quality.

To ensure the safe use of a propane heater in a greenhouse, it is important to follow the manufacturer’s instructions carefully, choose an appropriate heater size for the greenhouse, and install proper ventilation to ensure good air circulation. Regular maintenance and inspections are also important to prevent gas leaks and other safety hazards.

How Can I Heat My Greenhouse for Free?

Heating a greenhouse for free may not seem realistic, but there are a few ways to do it.

Here are some methods you can consider:

Passive Solar Heating… One of the easiest ways to heat a greenhouse for free is by using passive solar heating. This involves placing the greenhouse in a location that receives plenty of sunlight and using materials that can absorb and retain heat, such as stone or brick. You can also consider installing a solar panel to generate electricity to run a small heating unit.

Compost Heating… You can use compost to create heat for your greenhouse. Compost generates heat as it breaks down, and you can harness this heat by placing the compost pile in or near the greenhouse. The heat generated by the compost can help keep the greenhouse warm during colder months.

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Insulation… Proper insulation is essential to keep the heat inside the greenhouse. You can insulate your greenhouse with materials such as bubble wrap or foam board insulation to prevent heat loss.

Geothermal… Geothermal heating is another method that you can consider. This involves using the natural heat of the earth to warm your greenhouse. You can install a geothermal heating system, which involves burying pipes underground, to circulate warm water or air through the greenhouse.

Use Waste Materials… You can use waste materials, such as old newspapers or cardboard, to insulate the greenhouse. These materials can be stuffed between the layers of plastic or glass, creating a layer of insulation that traps heat inside the greenhouse.

Remember that the effectiveness of these methods will depend on the climate and size of your greenhouse, so it’s best to experiment and see what works best for your situation.

How Do You Winterize a Greenhouse?

Winterizing a greenhouse is important to protect plants from the harsh winter conditions, such as low temperatures, frost, and snow.

Here are some steps you can take to winterize your greenhouse:

Insulate the Greenhouse… Insulating the walls, roof, and foundation of the greenhouse can help maintain a stable temperature inside. You can use bubble wrap, polythene, or special insulation materials to create a barrier against the cold.

Seal Gaps and Cracks… Seal any gaps or cracks in the greenhouse structure to prevent cold drafts from entering. Use weather stripping, caulk, or foam insulation to seal around windows, doors, and vents.

Thermometer… Use a thermometer to monitor the temperature inside the greenhouse and adjust the heater as needed. Try to maintain a temperature between 45°F and 55°F for most plants.


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Ventilate the Greenhouse… On sunny days, it is important to ventilate the greenhouse to prevent overheating. Open vents or windows to allow fresh air to circulate.

Water Plants Carefully… During the winter, plants may require less water than in the summer. Be careful not to overwater, as excess moisture can lead to fungal growth and other problems.

Protect Plants from Frost… Cover plants with blankets, burlap, or other materials to protect them from frost. You can also use frost cloths or row covers to provide additional protection.

Related Reading

How to Choose a Lean-to Greenhouse Kit
10 Benefits of an Indoor Greenhouse
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How to Build Your Own Indoor Greenhouse Cabinet


While most people don’t use their greenhouse in the winter, especially if you live in a area the has harsh winters. If you live in a place that has milder winters it can be feasible to heat your greenhouse, which allows you to grow all year round.