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How Much Warmer Is An Unheated Greenhouse?

How Much Warmer Is An Unheated Greenhouse

You might be wondering how much warmer an unheated greenhouse is. The truth is, unheated greenhouses can experience wild temperature fluctuations, particularly during the winter and summer. To be prepared, you should be vigilant about the forecast. But even if you don’t want to spend much money on heaters, there are ways to regulate the temperature inside your greenhouse.

Bubble wrap

If you have an unheated greenhouse, insulating it with bubble wrap will help to retain heat and prevent your plants from dying during the winter. You can purchase horticultural bubble wrap at garden centers. Choosing larger diameter bubbles will help prevent cold air from escaping from your greenhouse. Using clear tape, attach the bubble wrap to the walls of your greenhouse. Always remember to wrap the flat side of the bubbles so they face outward.

Before wrapping the greenhouse, wash it thoroughly to remove dirt. Also, check all windows and panes for any holes or damages. If the greenhouse is made from glass, you need to make sure the bubble wrap won’t block any of the glass. Remember that bubble wrap can trap moisture inside the greenhouse, which can encourage disease and mould. You also need to keep your greenhouse ventilated in order to avoid excess condensation.

Propane heaters

Propane heaters can be used to keep greenhouses warm during the winter. They use kerosene, natural gas, or propane as fuel. Propane heaters are typically clean-burning and should be adjusted to optimal efficiency. However, inefficient combustion can cause harmful pollutants to escape into the greenhouse. These pollutants can affect both the plants and the people working inside.

Propane heaters are best installed near the greenhouse. When choosing the best location, contact a reputable propane supplier for placement suggestions. Propane heaters should be installed low on the interior wall, close to the ground. The heaters should also rise from the ground, preventing cold spots. Propane companies usually provide a service team to install the tank and piping. They will also test the heater to make sure it doesn’t leak.

Solar-powered heaters

In winter, unheated greenhouses are significantly cooler. This is because the daylight hours are shorter and the greenhouse doesn’t get as much heat at night as it does during the day. In addition, the temperature inside will meet outdoor temperatures, and this means you have to rely on some other method to warm your greenhouse.

There are a few ways to keep your greenhouse warmer than the outside temperature. One method is to add thermal mass. This mass helps to retain and release heat. Compost piles generate heat during the decomposition process, and this heat can be transferred to the greenhouse’s interior. The amount of heat generated depends on the size and moisture of the compost pile, and the surrounding air temperature. Another option is to add thermal mass objects to your greenhouse, such as rocks or paving bricks.

Germination mats

When using Germination mats in an unheated climate, it’s important to monitor soil temperature carefully. Seedlings can become weak if the temperature is too high, so check the thermostat periodically. In addition to monitoring soil temperature, seedlings should be placed under bright light soon after germination. The seedlings may need to be moved to a cooler room until the air temperature warms up.

The temperatures that mats reach will vary depending on the model, but most range from 68 to 110 degrees Fahrenheit. This temperature range is sufficient for germinating seeds or sprouting exotic plants. Heat mats can also be used to provide heat in cold basements.

Other support structures

When setting up your greenhouse, there are several different support structures that you can use. One option is a bench. The benches can either be side benches or center benches. The side benches should be no wider than your work area. The center benches can be 6 feet wide. Be sure to choose a color that reflects light.

Another option is a shadehouse. These structures come in various styles, from a cable-frame structure to a retractable roof system. They are often more affordable than a rigid-frame greenhouse.


There are two primary methods for ventilating an unheated greenhouse: natural ventilation and mechanical ventilation. Natural ventilation is best when it is part of the design at the start of the project, but mechanized ventilation is equally effective even after it is installed. Mechanized ventilation uses a mechanical device that opens and closes vents at a set time. It can be installed on the roof or side walls. Rolling up walls can also help with ventilation.

The method for ventilating an unheated greenhouse depends on the age of the structure and its condition. An older greenhouse may have cracks or holes in the covering material. If the greenhouse is constructed with large sheets of glazing or fiberglass, a large amount of cold air may be able to enter. Alternatively, use single or double layers of rigid or flexible plastic to minimize infiltration.