18 Ways to Keep A Greenhouse Warm Without Electricity in Winter

Winter 2025 is approaching. If your commercial greenhouse relies heavily on grid electricity to get through the cold season, your winter operating costs may rise substantially—especially in Europe’s high‑latitude regions. The study shows, in H1 2022, EU wholesale electricity prices reached about €199/MWh, roughly four times the 2010–2020 average, while Germany and France saw increases of 36% and 48%, respectively. This has helped keep European power prices elevated into 2025. You may not be in Europe; regardless, reducing reliance on electricity during winter is a prudent operating choice for greenhouses.

So, how can you keep your greenhouse warm without electricity? In this post, INSONSHADE’s greenhouse experts share 18 no‑electric (or ultra‑low‑electric) methods to help you maintain winter climate conditions more efficiently while protecting crop growth.

How to Warm a Greenhouse Without Electricity

Method	Principle	Simplicity	Cost
Ensure Proper Sealing	Reduce air leaks to cut convective losses	Easy	Low
Regularly Clean the Cover	Improve solar gain by keeping surfaces clear	Easy	Low
Add More Insulation (straw/corn stalks)	Add exterior insulation to slow heat loss	Easy	Low
Hang Reflective Sheets	Reflect light back onto the canopy to raise gains	Easy	Low
Managing Insulation Blankets	Close at night, open by day to control swings	Moderate	Low–Mid
Set Up an Inner Greenhouse	Create an inner air layer to reduce losses	Moderate	Low–Mid
Use Mulch and Water Beneath It	Stabilize soil temperature and reduce evaporation	Easy	Low
Digging a Frost‑Proof Trench	Thermal buffer to protect and stabilize soil	Moderate	Low–Mid
Apply Organic Fertilizer	Improve soil structure and thermal inertia	Easy	Low–Mid
Insulation Curtains	Create an air barrier below the roof	Moderate	Mid-High
Solar Air Heaters	Collect and deliver solar heat to the air	Moderate	Mid-High
Eco‑Friendly: Raising Poultry Inside	Add background animal heat; integrated cycle	Moderate	Low–Mid
Create Smoke Around the Greenhouse	Warm boundary layer around the structure	Moderate	Low
Use Open Flames for Heating	Direct combustion heat (high safety demands)	Moderate	Low–Mid
Heat Distribution with Small Pots	Small flame for localized heating	Easy	Low
Water‑Barrel Thermal Mass	Store day heat in water, release at night	Easy	Low
Compost Heating	Aerobic decomposition releases usable heat	Moderate	Low–Mid
Chinese‑Style Passive Solar Greenhouse	Passive solar with mass walls and night insulation	Complex	Mid-High

We’ll introduce these 18 methods in detail to help you find the best fit for your greenhouse. Many tips are inspired by practices from northern China’s cold, remote regions.

1. Ensure Proper Sealing

Whether it’s a small garden greenhouse, a medium-sized one, or a large commercial greenhouse, keeping it well-sealed is essential in winter. For garden greenhouses, you can seal gaps with everyday materials like cardboard, blankets, or frost cloth to keep cold air out. For commercial greenhouses, focus on managing ventilation systems to ensure they are properly opened and closed to maintain the correct temperature. Night sealing is critical: after sunset, close and check all vents, doors, and service openings, and add door curtains or draft stoppers to reduce nocturnal heat loss when temperatures drop fastest.

2. Regularly Clean the Greenhouse Cover for Better Light

Whether you use plastic, polycarbonate panels, or glass in your greenhouse, you should start cleaning it in the fall and regularly clear away dust and leaves. This will improve light penetration, which in turn raises the temperature inside. After snowfall, promptly remove the snow to let sunlight into the greenhouse and boost temperatures.

3. Add More Insulation

This method works for both garden greenhouses and larger commercial setups. You can surround the greenhouse with a layer of materials like corn stalks or straw, compressing them tightly. This will prevent cold air from entering and help retain heat. This simple and effective method helps maintain a stable temperature inside the greenhouse.

4. Hang Reflective Sheets

In winter, many greenhouse owners in northern China hang reflective sheets on the north side of their greenhouses. When the sun shines from the south, the reflective sheets help bounce light back onto the plants, increasing the amount of light and the greenhouse’s overall temperature. Make sure to adjust the position of the reflective sheets according to your region’s location in the Northern or Southern Hemisphere.

5. Managing Insulation Blankets

This method is mainly used in subarctic and arctic regions. The timing of uncovering and covering insulation blankets is crucial during winter. The general rule is to adjust according to sunrise and sunset. On sunny days, the blankets can be uncovered between 8:30 and 9:00 a.m. and covered again around 4:00 to 4:30 p.m. However, the exact times should be flexible based on local weather conditions. The key is to avoid a rapid temperature rise inside the greenhouse, so uncover and cover at appropriate times.

6. Set Up an Inner Greenhouse

Building an inner greenhouse creates an additional protective layer for large greenhouses. This double-layer structure can significantly enhance insulation. For small garden greenhouses, adding an extra layer of covering, such as bubble wrap, provides an extra thermal layer, helping prevent heat loss and keeping the temperature stable. Bubble wrap is also affordable, making it an excellent option for home greenhouses.

7. Use Mulch and Water Beneath It

Mulch is an effective way to stabilize soil temperature, suitable for most greenhouses except hydroponic ones. In winter, it’s recommended to use raised beds covered with mulch. When watering, it’s best to irrigate under the mulch or, even better, use drip irrigation if your budget allows. Additionally, spreading wood ash between vegetable rows can help retain heat.

Winter Watering Tips: Plants are already stressed by lower winter temperatures, so try to reduce watering unless necessary. Instead of large amounts of water, use sun-warmed water stored in a sunlit tank inside the greenhouse. Water in the late morning on sunny days to avoid sudden drops in soil temperature.

8. Digging a Frost-Proof Trench

Digging a frost-proof trench is a very effective way to stabilize soil temperature, especially for small greenhouses. Maintaining soil temperature during winter is crucial for crop growth. For example, in northern China, many greenhouse owners dig a trench along the south-facing side (the sunny side) of their greenhouses before winter. The trench is usually about 1 meter deep and 0.5 meters wide. It is filled with sawdust, weeds, manure, and straw, then covered with soil and a plastic film layer. This technique helps prevent heat loss from the soil and ensures that crop roots continue to grow during the coldest months.

9. Apply Organic Fertilizer

Applying organic fertilizer is another great way to stabilize soil temperature. Experienced greenhouse owners usually apply 5 cubic meters of well-composted organic fertilizer per acre before planting, mixing it with microbial fertilizer or using 1,000 pounds of commercial bio-organic fertilizer. This not only provides essential nutrients for crops but also improves soil structure, which in turn helps to keep the soil warmer during winter.

10. Insulation Curtains for Greenhouses

Although insulation curtains typically require electricity to open and close, power is needed only during operation. Many large commercial greenhouses install energy-saving thermal curtain systems to reduce energy costs and maintain warmth in winter. These curtains create an air barrier between the greenhouse roof and the curtains, with high-quality insulation curtains offering up to 70% energy savings.

11. Solar Air Heaters

Solar air heaters are simple, effective collectors that directly heat air and deliver it into the greenhouse. For winter performance, set the collector tilt to approximately your latitude + 15° to 20°, and size the collector at roughly 0.15–0.3 m² per 1 m² of greenhouse floor area (adjust for local sun and insulation). Well-designed units typically achieve about 35%–70% thermal efficiency. Pair solar air heaters with ample thermal mass so excess daytime heat can be stored and released at night.

12. Eco-Friendly Greenhouses: Raising Poultry Inside

Some homeowners keep chickens or rabbits inside their greenhouses, which can generate heat in a small space. Chickens, for instance, help control pests and weeds without pesticides while also loosening the soil. Additionally, chicken manure serves as a natural fertilizer, boosting plant growth. This natural cycle allows you to grow vegetables and raise poultry simultaneously, creating a win-win situation.

13. Create Smoke Around the Greenhouse

Before cold fronts hit, some regions burn straw or other materials around the outside of greenhouses. The heat from the smoke helps to raise the temperature around the greenhouse, reducing the impact of the cold. As with biomass combustion in general, always prioritize safety and local compliance.

14. Use Open Flames for Heating

In some areas, greenhouse owners use open flames for heating, such as burning charcoal with accelerants. While this method can effectively raise temperatures, it carries significant safety risks. Incomplete combustion can generate carbon monoxide (CO), so a compliant chimney and adequate fresh-air supply are essential. Open-flame heating is more common in small- and medium-sized greenhouses, but caution is needed, as many covering materials are flammable. Always keep flames away from plastic films and use barriers for added safety.

15. Heat Distribution with Small Pots

This method also involves open flames but is more suited for small greenhouses. According to online resources, the principle is to burn alcohol or other flammable substances using small clay pots to distribute heat evenly. Treat it with the same safety standards as any open-flame heating and monitor closely.

This method is ideal for garden greenhouses, while open flame heating is better suited for small to medium greenhouses. Since both involve fire, it is important to monitor the situation closely to ensure greenhouse safety.

16. Water-Barrel Thermal Mass

Water has a high specific heat capacity and is a low-cost, low-maintenance thermal mass. A common approach is to place large, dark-colored barrels (e.g., 55-gallon) along the north wall or other sunny areas so they absorb heat during the day and release it at night. Although precise performance figures are limited, field practice shows this is a cost‑effective option for budget‑constrained home or community greenhouses.

17. Compost Heating

Under aerobic conditions, a well‑managed compost pile can sustain internal temperatures of about 50–70°C and provide usable heat. Properly managed systems can raise greenhouse temperatures by roughly 2–3°C or produce hot water up to ~55°C when water coils (e.g., PEX) are embedded in the pile. Key maintenance parameters include C:N ≈ 25–30:1, moisture ≈ 50–60%, and adequate aeration.

In practice, a compact aerated static pile (ASP) can be assembled from local biomass and a small blower or inline fan to extract warm air into plant zones. Keep heat hardware separate from plants, provide a fresh‑air supply, and manage odor/condensate; this approach offers a low-electricity, renewable-heat supplement during prolonged cold spells.

18. Chinese‑Style Passive Solar Greenhouse

If you are yet to build a greenhouse and want to minimize winter electricity use, consider the Chinese‑style passive solar greenhouse. It relies on three solid walls (north, east, west—often brick or clay) to store heat, with a south‑facing transparent covering to maximize solar gain; at night, insulation blankets/curtains reduce heat loss. In cold weather, well‑executed designs can keep the interior up to about 25°C (≈45°F) warmer than outside using solar energy alone.

This is a low‑tech, highly energy‑efficient, and cost‑effective model suited to regions with large day‑night swings and to larger‑scale production. Limitations include the need for precise site orientation and the lower durability of plastic films versus glass. For background and design guidance, see this overview of the Chinese‑style greenhouse.

FAQs

1) Can solar alone keep my greenhouse warm through the night?
Not reliably. A solar air heater can lift daytime temperatures (typical efficiency ≈35%–70%), but pair it with thermal mass for night retention. In prolonged cold or low-sun periods, consider supplemental sources.

2) I’m on a tight budget—what should I do first?
Seal leaks, clean covers, add low-cost insulation, and consider adding simple thermal mass (e.g., water barrels). These passive steps usually deliver the best ROI.

3) How effective is compost heating?
Properly managed compost systems can raise greenhouse temperatures by about 2–3°C or produce hot water up to ~55°C, provided correct C:N ratio (~25–30:1), moisture (~50–60%), and aeration are maintained.

4) What’s robust for prolonged cold or cloudy periods?
A biomass stove with a compliant chimney and adequate fresh-air supply offers dependable backup heat. For mid-to-large projects, ground-coupled systems (EAHE) provide a stable baseline for warming but require a higher upfront investment.

Conclusion

This article outlines 18 energy-saving methods suitable for everything from home greenhouses to large commercial operations. These methods help keep your greenhouse warm during the winter and reduce energy costs. Whether you’re a beginner or an experienced grower, these tips can offer practical solutions to help your greenhouse run more efficiently through the winter.

Please contact us if you are involved in large-scale greenhouse farming and urgently need winter warming solutions. As a professional agricultural protection manufacturer, INSONSHADE offers a range of greenhouse protection solutions, including climate curtain systems, to help your crops withstand the challenges of winter.