We know that greenhouse insulation is a horticultural task that must be taken seriously during winter. Gardeners can learn about the many ways to insulate their greenhouses in various ways. You may need to buy insulation materials, but do you really need them? Or, do you know what kind of greenhouse insulation you need? Do you have doubts about these similar questions?

Common Material for greenhouse insulation

Horticultural bubble wrap

Bubble wrap is considered one of the best insulation materials for greenhouses. These materials are inexpensive, easy to use, and widely applicable.

Using bubble wrap to seal gaps in the greenhouse frame can reduce the rate at which heat escapes. When choosing bubble wrap, experienced gardeners know that the bigger the bubble, the better. This is because larger bubbles allow more light to enter the greenhouse and provide better insulation.

Some horticultural bubble wraps have more features such as UV resistance. When choosing a gardening bubble wrap, pay attention to these additional features, and you may be more pleasantly surprised.

Horticultural bubble wrap can be easily attached to the interior of greenhouse kits such as portable greenhouses, aluminum greenhouses, wooden greenhouses, and more. Even if you are facing the challenge of winterizing your greenhouse for the first time, you can learn to set up horticultural bubble wrap in a very short time.


Strictly speaking, sealant cannot be counted as a greenhouse insulation material. But no matter what kind of insulation you want to use to help your greenhouse survive this winter, you'll need a sealant to fill cracks in your greenhouse structure before everything is done.

The most popular sealant available is silicone caulk; other sealants may not be as durable and easy to use as this.

sealant for greenhouse                     (sealant for greenhouse)

Remember, checking the greenhouse seal is a prerequisite for all greenhouse insulation measures. Once the greenhouse sealing process goes wrong or is overlooked, your next horticultural tasks will face many challenges.


Polycarbonate is particularly good at insulating greenhouses. This material is lightweight, UV resistant, and flexible. Moreover, most polycarbonate sheets maintain excellent quality at temperatures below -40°F and up to 284°F.

Most polycarbonate sheets are made using hollow multilayer walls with air pockets. Double-walled panels are commonly used to insulate greenhouses. If you want better greenhouse insulation, triple-wall panels are better because of their excellent insulation properties and superior strength.

If you plan to choose polycarbonate to insulate your greenhouse, it is important to note that the thicker the polycarbonate, the lower the light transmission. Thicker polycarbonate improves insulation by about 30%, but light transmission may be reduced by about 10%.

Gardening Fleece

Horticultural wool is a gardening material that can be used all year round. In the winter, gardeners often use horticultural wool to protect plants from frost, rain, snow, high winds, or hail. If your greenhouse is unheated or unheated, horticultural wool can be used to wrap or cover plants to provide protection.

Heavy-duty horticultural wool can be used as an alternative to polyethylene as greenhouse insulation. You can use clips or double-sided sticky pads to secure heavy-duty horticultural fleece to the inside of your greenhouse.

gardening fleece          (gardening fleece)

Horticultural fleece is available in a variety of sizes. You can find different qualities and weights of horticultural wool. If used with care, good quality horticultural wool will last for several years and has the advantage of being UV-resistant, tear-resistant, and rot-resistant.

The disadvantage of most horticultural wool is that it cannot be used multiple times, so if you want to choose horticultural wool for greenhouse insulation, you should try to choose a good quality horticultural wool that lasts for a long time.

Heavy-duty Polyethylene

Polyethylene materials are often used in agricultural, commercial, and domestic greenhouses. These materials are usually inexpensive and come in large rolls. Most gardeners prefer to insulate their greenhouses by fixing polyethylene material to the outer frame of the greenhouse.

It is ideal to use polyethylene on wood and metal-framed greenhouses, but it is not recommended to use polyethylene directly on PVC-framed greenhouses unless you have primed the frame in advance. Exposed PVC will degrade polyethylene with increased use.

Polyethylene Carbonate

Polyethylene carbonate is a hard and durable option. Although polyethylene carbonate lasts a long time, it is also relatively expensive. Polyethylene carbonate is generally more expensive than polycarbonate, and for some gardeners, polyethylene carbonate is a less cost-effective option. Polyvinyl carbonate is usually multilayered to withstand strong winter winds. Polyethylene carbonate is usually slightly milky in appearance and available in a variety of transparency.

Polystyrene foam sheets

When we discuss greenhouse insulation, we may overlook the greenhouse foundation. However, cold air can enter the greenhouse through the foundation, which can result in approximately 15% heat loss. You can use some polystyrene foam panels that are about 2 inches thick to insulate the outdoor boundary of your greenhouse. These plastic sheets need to be vertically aligned and extended down into the soil to at least one foot. In addition, you should choose the right material to strengthen the greenhouse foundation to reduce heat loss. Gravel, clay, and peat rock are good choices. Cement, concrete, and wood are not recommended because of the poor insulation effect.

Other blackout fabrics

In addition to the materials mentioned above, you can also choose from a variety of blackout fabrics as well as fabrics for greenhouse insulation. Fabrics such as linen or old curtains, for example, can be used to wrap plants to protect them from frost.

In the online store, you can find all kinds of special shading clothes, such as:

  • Alumina reflective shading cloth. These aluminum shading cloths are usually made from a mixture of aluminum and various chemical fibers and are durable. The unique alumina properties reflect unwanted sunlight and harmful radiant heat in greenhouse greenhouses.
  • Knitted shade cloth. This type of shading cloth is usually made of a mixture of high-quality polyethylene cloth and other fabrics, which has the characteristics of high strength and durability. The gardener can freely cut the shade cloth according to the size of the greenhouse. The knitted design ensures no tearing and wear, and is easy to use.

How to choose the right greenhouse insulation material

Your greenhouse sizes

If your greenhouse size is small, you will not incur much expense no matter which insulation material you choose. Your choices are many; polycarbonate, polyethylene, aluminum oxide reflective shade cloth, and other materials are available as options.

Generally speaking, greenhouses smaller than 6'x8' in size are considered small. For example, Quictent 71 "x36 "x36" mini greenhouse, Quictent 56 "x29 "x77" indoor greenhouse. if you want to insulate this type of greenhouse, horticultural fleece, polyethylene cloth, and other inexpensive and easily available materials are perfectly suited to insulate your greenhouse.

If you have a large greenhouse, you need to think more about the choice of insulation material. If you want to choose more expensive materials such as polycarbonate, you have to accept the high cost of materials. However, this does not mean that inexpensive materials such as horticultural wool are the best choice, because you must consider the insulation effect of these materials and whether these materials will cause adverse effects on the plants.

Your greenhouse material

We know that some greenhouse insulation materials are not suitable for certain types of greenhouses, such as heavy-duty polyethylene can perform perfectly in wood and metal frame greenhouses, but cannot be used directly in PVC frame greenhouses. This is because exposed PVC degrades polyethylene.

Therefore, it is not the high-end material that looks better. If you need to choose greenhouse insulation materials in winter, you need to know your greenhouse materials in advance.

white greenhouse             (white greenhouse)

You need to know what your greenhouse is made of, whether it will react chemically with other materials, and whether the insulation material you want will be able to cover your greenhouse directly. These are all issues that need to be considered because you don't want to find out about the problem only when you are using it.

Take the Quictent 20' x 10' x 7' Heavy Duty Large Greenhouse as an example.

This heavy-duty greenhouse is perfect for winter use because its frame is made of galvanized steel frame, which is durable and strong enough to withstand winter winds and rain.

20' x 10' x 7' Heavy Duty Large Greenhouse (2 Colors Available)
  • Size: 10'x20'
  • Height:6.6'
  • Benefits: Reinforced Top Structure, Two Doors in One

The shape of this greenhouse is a round arch, if you want to insulate this greenhouse, bubble wrap, gardening wool, and polyethylene are all options. There is currently no definitive material to prove that adverse chemical reactions occur between polyethylene and galvanized steel. Polyethylene carbonate is not an ideal option because it is an expensive material.

Your budget

How much do you plan to spend on greenhouse insulation in the winter? If your budget is very limited, horticultural wool, bubble wrap, plastic, and fabric are the most suitable materials for you because they are cheap and easy to use. Although bubble wrap is cheap, it is widely used and insulates well, making it one of the most ideal materials for greenhouses on a budget.

If you don't set a limit for your budget, you're more concerned about greenhouse insulation, bubble wrap, heavy-duty Polyethylene, Polyethylene Carbonate, and polystyrene are all excellent options.

Certain materials are expensive but durable, tough, and insulate well. In the short term, materials like Polyethylene Carbonate can incur significant expenses, but they will serve your greenhouse well for a long time and remain cost-effective.

Material longevity

Do you care about the service life of your chosen greenhouse insulation material? Are you planning to try new material the next year? Do you want to choose a material that will last for a long time?

If you are only thinking about insulating your greenhouse this winter and don't have a specific long-term plan, try options such as horticultural wool (many types of horticultural wool only last one season), bubble wrap, and fabric first. These materials are suitable for greenhouse novices.

If you're looking for materials that can be used for a long time, bubble wrap, heavy-duty Polyethylene, Polyethylene Carbonate, and polystyrene are better choices. These materials can be used for a long time and the thermal insulation effect is stable.

Your area

Greenhouses located at high altitudes face more challenges in winter, and weather such as snowstorms and hail are serious challenges for greenhouses.

For your greenhouse to survive this winter in bad weather, it is necessary to choose materials with high strength, strong durability, and good thermal insulation. Plastics, fabrics, , and horticultural wool are the materials that will not give your greenhouse the best protection in bad weather. You need reinforced greenhouse insulation.

If your greenhouse is set up in a temperate climate, you can protect your greenhouse with a mix of materials.


Choosing a greenhouse insulation material is never easy. You don't have to be a materials expert, but you do need to know at least some of the characteristics of common materials and know your own greenhouse.

The cold winter is equal for everyone, and you can only get your plants through this winter smoothly in a warm indoor environment if you do the best possible insulation work.


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