How Do You Winterize A Portable Greenhouse?

Imagine it’s that time of year again when the temperature drops and winter is on its way. You’ve invested in a portable greenhouse to protect your precious plants from the harsh weather, but now you’re left wondering: how do you winterize a portable greenhouse? Don’t worry, in this article, we’ll guide you through the steps to ensure your greenhouse is ready to withstand the cold and keep your plants thriving throughout the winter months. So grab your gloves and let’s get started!

Preparing the Portable Greenhouse for Winter

One of the most important steps in winterizing a portable greenhouse is cleaning and organizing the interior. This helps to eliminate any potential pests or diseases that could overwinter in the greenhouse and provides a clean and welcoming space for your plants. Start by removing all debris, including dead plants, leaves, and any other clutter. Sweep or vacuum the floor to remove any dirt or dust. Once the interior is clean, organize your gardening tools and supplies, making sure everything has its designated place. This will make it easier to find what you need and keep the greenhouse tidy throughout the winter months.

After cleaning and organizing, it’s time to remove and store any summer plants that won’t survive the cold temperatures. Start by carefully uprooting the plants, taking care not to damage their roots. Shake off any excess soil and transfer the plants to pots or containers, if necessary. Choose a suitable storage location for each plant, considering factors such as light requirements, temperature, and humidity. Label the containers to avoid confusion when you want to reintroduce the plants in the spring. Remember to provide adequate care for these plants during the winter months, including proper watering and sufficient light.

Next, take the time to inspect and repair any damaged components in your portable greenhouse. Check for cracks in the panels or windows, as well as any loose or broken parts. Repair or replace damaged components to ensure that your greenhouse remains structurally sound throughout the winter. Performing these repairs now will save you time and effort in the long run and prevent any further damage from occurring during the colder months.

Adding insulation to your portable greenhouse is crucial for maintaining a stable and favorable environment for your plants. Insulation helps to retain heat, keeping the temperature inside the greenhouse at a suitable level. There are various insulation materials available, such as bubble wrap or polystyrene sheets, that can be easily installed on the walls, ceiling, and even the floor of the greenhouse. The insulation material should be secured tightly to prevent air leaks and maximize its effectiveness. Remember to leave sufficient ventilation openings to ensure proper air circulation.

Sealing any air leaks is imperative when preparing your portable greenhouse for winter. Even small gaps or cracks can let in cold air and compromise the temperature and humidity levels inside the greenhouse. Use weatherstripping or silicone caulk to seal any openings around windows, doors, or panels. Pay special attention to corners and joints where air can easily escape. Properly sealed, your greenhouse will be better able to maintain the ideal conditions for your plants during the winter months.

Checking and repairing the door of your portable greenhouse is essential for preventing drafts and maintaining proper insulation. Inspect the door for any signs of damage or wear and tear. Replace any broken parts, such as hinges or latches, and ensure that the door closes tightly. If necessary, consider adding weatherstripping or a draft excluder to the bottom of the door to prevent cold air from entering.

Protecting the greenhouse’s floor is often overlooked but can make a significant difference in maintaining a stable environment for your plants. Insulating the floor helps to prevent cold drafts and minimize heat loss. You can use materials like foam insulation boards or a layer of mulch to provide insulation. Additionally, placing a barrier, such as a tarp or plastic sheet, between the ground and your greenhouse floor can help further protect against moisture and cold temperatures.

Installing ventilation in your portable greenhouse is crucial for air circulation, which helps to prevent the buildup of excess moisture and stale air. Ventilation also helps regulate temperature and humidity levels, creating a healthier environment for your plants. Consider installing vents or fans near the top and bottom of the greenhouse to allow for proper air exchange. These vents can be manually operated or automated, depending on your preference and budget. Monitor the temperature and humidity levels inside the greenhouse regularly to ensure they are within the optimal range for your plants.

Wrapping or covering the greenhouse is an additional step you can take to provide extra insulation and protection against harsh winter conditions. You can use thermal blankets, shade cloth, or even bubble wrap to cover the greenhouse. Ensure that the coverings are securely fastened but still allow for proper air circulation. The covering should also be able to withstand wind and snow loads. Remember to periodically check the coverings for any damage or loosening and make any necessary adjustments.

Lastly, it’s essential to prepare for snow and ice during the winter months. Clear excess snow from the roof and the surrounding area to prevent it from collapsing on your greenhouse. Use a snow rake or a broom to safely remove the snow. If necessary, install heating cables on the roof to prevent the buildup of snow and ice. Additionally, consider using mats or gravel around the greenhouse to provide traction and prevent slipping on icy surfaces.

Maintaining Temperature and Humidity Levels

Maintaining proper temperature and humidity levels in your portable greenhouse is crucial for the health and growth of your plants during the winter months. Here are some tips to help you achieve this:

Using a portable heater is an effective way to regulate the temperature inside your greenhouse. Choose a heater that is suitable for the size of your greenhouse and provides the desired amount of heat. Place the heater in a safe location, away from flammable materials and ensure proper ventilation when using the heater.

Insulating the ground inside the greenhouse helps to maintain a consistent temperature. Use insulation materials, such as foam boards or straw, to create a barrier between the ground and your plants. This prevents the cold from seeping into the greenhouse and affecting the temperature.

Monitor and adjust the temperature inside the greenhouse regularly. Invest in a reliable thermometer or thermostat to keep track of the temperature. Adjust the heater or ventilation accordingly to ensure that the temperature remains within the desired range for your plants.

Providing sufficient ventilation is important for maintaining proper airflow and controlling humidity levels. Proper ventilation helps to prevent the accumulation of excess moisture, which can lead to mold and disease. Adjust the vents or fans to allow for the exchange of air without causing excess cooling or drafts.

Misting or spraying water inside the greenhouse can help maintain humidity levels, especially during dry winter months. Use a fine mist or spray bottle to lightly mist the plants and surrounding surfaces. Be careful not to overwater or create excessive moisture, as this can lead to fungal diseases.

Using a humidifier or damp sandboxes is another option to increase humidity levels in your portable greenhouse. Humidifiers can be placed strategically to release moisture into the air, while damp sandboxes can provide localized humidity around specific plants.

Protecting Plants from Frost and Cold Temperatures

Protecting your plants from frost and cold temperatures is crucial to ensure their survival throughout the winter. Here are some strategies you can employ:

Choosing cold-tolerant plants is a proactive approach to winterizing your portable greenhouse. Research and select plants that are adapted to cold climates and can withstand low temperatures. These plants are more likely to survive and thrive during the winter months.

Covering plants with protective sheets or blankets is a simple yet effective way to shield them from frost. Use lightweight fabric or frost protection blankets to cover sensitive plants overnight or during particularly cold spells. Ensure that the covering is secure but not too tight to allow for proper air circulation.

Using frost cloths or floating row covers provides extra insulation and protection for your plants. These materials can be draped over individual plants or entire rows and provide a barrier against frost, wind, and cold temperatures. They allow sunlight and moisture to penetrate while keeping the plants warm.

Utilizing portable plant covers or cloches is an option for protecting delicate plants. These covers create a microclimate around individual plants and provide insulation against cold temperatures. Cloches can be made of glass, plastic, or even repurposed containers like milk jugs or soda bottles.

Using heat lamps or string lights can provide additional warmth to your plants during the winter months. Place heat lamps or string lights strategically to provide supplemental heat, especially during extremely cold nights. Be cautious when using these heat sources, as they can be a fire hazard if not properly installed and monitored.

Implementing mulching techniques is a beneficial way to protect plant roots from freezing temperatures. Apply a layer of organic mulch, such as straw or wood chips, around the base of your plants. Mulch helps to insulate the soil, preventing it from freezing and protecting the roots.

Watering plants properly is essential for winter plant care. As temperatures drop, it’s important to adjust the watering schedule to prevent overwatering or waterlogged soil, which can lead to root rot. Water only when necessary and ensure adequate drainage to avoid water accumulation.

Avoid overcrowding plants in your portable greenhouse, as this can increase the risk of frost damage. Proper spacing allows for better airflow and reduces the chances of frost forming on the plants. Follow recommended spacing guidelines for each plant to ensure optimal growth and protection.

Preventing Pest Infestations

Preventing pest infestations in your portable greenhouse is crucial for the health and well-being of your plants. Here are some strategies to keep pests at bay:

Cleaning and sanitizing the greenhouse is an important step in preventing pests. Remove any leftover plant debris or fallen leaves, as they can attract pests. Thoroughly clean all surfaces, including benches, pots, and tools. Use a bleach solution or eco-friendly disinfectant to sanitize the greenhouse.

Inspecting plants for pests regularly is essential for early detection and prevention. Check the leaves, stems, and undersides of the plants for any signs of pests or damage. Look for pests such as aphids, mites, or whiteflies. If you notice any pests, isolate the affected plants and treat them promptly.

Using sticky traps or insect barriers is an effective method for trapping and monitoring pests. Place sticky traps or barriers in strategic locations around the greenhouse to catch flying insects and crawling pests. Regularly check and replace the traps as needed.

Implementing biological controls involves introducing beneficial insects or organisms that prey on pests. Ladybugs, lacewings, and predatory mites are examples of beneficial insects that can help control common greenhouse pests. Introduce them into your greenhouse as a natural and eco-friendly pest control method.

Applying organic pest repellents can help deter pests from entering your portable greenhouse. Use natural pest repellents such as neem oil, garlic spray, or insecticidal soap. These repellents are safe for the environment and pose minimal risk to your plants.

Installing ultrasonic pest repellers is an innovative way to keep pests away from your greenhouse. These devices emit high-frequency sound waves that are inaudible to humans but can repel and deter pests. Place the repellers strategically around the greenhouse for maximum effectiveness.

Regularly monitoring for pests is essential to catch infestations early on. Perform routine inspections of your plants, paying close attention to the leaves, stems, and soil. Look for any signs of pests, such as chewed leaves, webbing, or droppings. Early detection allows for prompt action and minimizes damage to your plants.

Maintaining Air Circulation and Ventilation

Maintaining proper air circulation and ventilation in your portable greenhouse is vital for the overall health and well-being of your plants. Here are some tips to ensure optimal airflow:

Clearing snow and debris from vents and the roof is crucial to maintain proper air circulation. After a snowfall or during the winter months, check your vents and the roof of your greenhouse regularly. Remove any snow buildup or debris that may impede the flow of air.

Using circulation fans or exhaust fans can help improve air circulation inside your portable greenhouse. Place the fans strategically to ensure that air is circulating evenly throughout the space. This helps prevent stagnant air pockets and promotes the exchange of fresh air.

Adjusting ventilation openings is essential to control the airflow inside your greenhouse. Open or close vents and windows as needed to regulate temperature, humidity, and airflow. Consider investing in automatic vent openers that respond to temperature fluctuations, ensuring consistent ventilation even when you’re not present.

Installing ventilation systems, such as ridge vents, gable vents, or louvers, is a long-term solution to ensure proper air circulation. These systems provide a constant exchange of air, helping to regulate temperature, humidity, and prevent the buildup of stale air. Consult with a professional to determine the best ventilation system for your portable greenhouse.

Maintaining proper airflow is key to preventing mold, mildew, and other fungal issues inside your greenhouse. Ensure that the airflow is not obstructed by overcrowded plants or equipment. Allow enough space between plants for air to circulate freely, and periodically rearrange them if needed.

Ensuring Proper Watering and Irrigation

Ensuring proper watering and irrigation is essential for the health and survival of your plants during the winter months. Here’s how you can take care of this aspect:

Monitoring soil moisture levels is crucial to prevent over or under watering your plants. Use a soil moisture meter or stick your finger into the soil to determine its moisture content. Adjust watering accordingly to ensure that the soil remains consistently moist but not waterlogged.

Adjusting the watering schedule is important when temperatures drop during the winter. Plants don’t require as much water during colder months, so reduce the frequency of watering. However, continue to monitor the moisture levels and provide water when necessary.

Using drip irrigation systems helps to deliver water directly to the root zone of your plants. This minimizes water waste and ensures that the plants receive a consistent and adequate water supply. Drip irrigation systems can be automated and adjusted to suit the specific needs of your plants.

Installing rainwater collection systems is a sustainable option for watering your plants during the winter. Collect rainwater from your rooftop or other sources and store it in barrels or tanks. This water can be used to irrigate your plants, reducing your reliance on tap water and conserving resources.

Avoiding overwatering is crucial to prevent root rot and other water-related issues. Ensure that excess water can drain freely from the pots or containers. Use well-draining soil mixes and pots with drainage holes to promote healthy root growth.

Mulching around your plants helps to conserve soil moisture and reduce evaporation. Apply a layer of organic mulch, such as wood chips or straw, to the soil surface. This helps to retain moisture and regulate temperature, creating a more stable environment for your plants.

Regular Maintenance and Care During Winter

Regular maintenance and care during the winter ensure that your portable greenhouse remains in good condition and your plants stay healthy. Here are some tasks to include in your winter maintenance routine:

Regularly checking the greenhouse for damage is essential to catch any issues early on. Inspect the structure, panels, windows, and other components for cracks, leaks, or signs of wear and tear. Promptly repair or replace any damaged parts to prevent further damage during the winter.

Clearing snow from the roof of your greenhouse and the surrounding area helps prevent overloading and potential collapses. Use a snow rake or broom to safely remove excess snow from the roof. Also, clear pathways around the greenhouse to ensure safe access and prevent any obstructions.

Removing ice buildup from the greenhouse is necessary to maintain a safe and functional space. Use a plastic shovel or ice scraper to carefully remove any ice on the pathways, doors, or windows. Apply an ice-melting product if necessary, but ensure that it is safe for your plants.

Preventing condensation and moisture issues is important for the health of your plants. Ventilate the greenhouse regularly to reduce humidity levels and minimize condensation. Wipe down any moisture that accumulates on the walls, windows, or plants. Insulate the greenhouse adequately to prevent temperature fluctuations that can cause condensation.

Cleaning and disinfecting the interior of the greenhouse is crucial for keeping pests and diseases at bay. Use a bleach solution or eco-friendly disinfectant to sanitize all surfaces, including benches, pots, and tools. Regular cleaning helps minimize the risk of pests and diseases overwintering in your greenhouse.

Pruning and trimming plants during the winter months help maintain their health and shape. Remove any dead or damaged branches to prevent the spread of diseases. Also, prune for shape and size to ensure proper airflow and prevent overcrowding. Use clean, sharp tools to minimize the risk of introducing infections.

Monitoring and adjusting temperature and humidity levels should be an ongoing task throughout the winter. Keep an eye on the temperature and humidity inside the greenhouse using a thermometer and hygrometer. Adjust the heating, ventilation, and misting systems as necessary to maintain optimal conditions for your plants.

Inspecting and repairing equipment is crucial to ensure that everything is in working order. Check your heaters, fans, thermometers, and other equipment regularly. Replace or repair any faulty components to maintain a safe and efficient operation.


Winterizing your portable greenhouse is crucial for the survival and well-being of your plants. By following the steps outlined in this article, you can ensure that your greenhouse remains a suitable environment for your plants throughout the winter. Proper cleaning, organizing, and preparation will set the foundation for a successful winter gardening experience. Maintaining temperature and humidity levels, protecting against frost, preventing pests, maintaining air circulation, and proper watering and irrigation are all essential aspects of winter greenhouse care. Regular maintenance and care during winter help keep the greenhouse in good condition and ensure the health of your plants. By investing time and effort into winterizing your portable greenhouse, you can enjoy the benefits of year-round gardening and protect your plants throughout the colder months.

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About the Author: Jake Scott