Are you a home gardener concerned about protecting your plants during the winter? You may live in a northern region and want to extend your growing season. Having a greenhouse for winter provides a sanctuary to grow crops while enjoying the beauty of your garden throughout the coldest months of the year. By implementing effective heating techniques in your greenhouse, you can cultivate an environment that nurtures and even enhances the growth of your plants year-round.
Place your greenhouse in a location with ample sunlight, wind protection, and easy accessibility. Opt for a traditional glass greenhouse for insulation, or choose a film and fabric option for budget-friendliness. Keep the greenhouse door closed in cold temperatures to retain heat and ensure it’s secure enough to prevent wandering, curious, and hungry animals from entering.
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When it comes to heating your greenhouse on cold days, several factors come into play, including your geographical location, the specific plants you are cultivating, and the quality of your greenhouse. This comprehensive guide walks you through constructing a winter greenhouse tailored to your gardening needs.
With simple strategies and practical advice, you will create an optimal environment for your flourishing plants, transforming your greenhouse into a vibrant oasis that brings joy and abundance throughout the year. Get ready to unlock the secrets to a successful and enchanting backyard garden on this exciting journey!
- Discover the perfect location for your winter greenhouse so you can extend your growing season and produce abundant harvests – even during the coldest months of the year!
- Save time AND money knowing which vegetables and herbs do well in greenhouses so you can cultivate mind-blowing yields all the way through spring.
- Discover which greenhouses are best for your budget and climate so you can enhance your harvests and boost your blooms.
Choosing The Perfect Location
The best greenhouse will be in the ideal location that receives plenty of sunlight, sturdy enough to protect from wind and other harsh outside elements, and offers convenient accessibility. Additionally, you’ll want to ensure your greenhouse is close to an abundant water source, like a spigot, to keep your plants watered.
The best location for your greenhouse is one that receives plenty of light throughout the late fall and winter. South-facing areas are particularly advantageous because they capture more light during this traditionally light-starved season.
By harnessing the natural heating power of the sun, your greenhouse can extend your growing season without the need for supplemental heating methods like LED grow lights or high-pressure sodium lights. The sun’s warmth will naturally heat the air during the day, creating a favorable and welcoming environment for your foliage friends. 1
To provide your greenhouse plenty of protection from the harsh winter winds, select a location that offers natural wind protection, such as a house, building, fence, or tree line. This shelter helps shield your greenhouse from solid gusts, prevents heat loss, and further winterizes your crops.
Like your backyard garden, you’ll want free and unhindered access to water. Having proximity to adequate hydration enables you to effortlessly provide the necessary moisture to your plants, ensuring their continued growth.
Moreover, access to electricity empowers you to operate essential equipment like fans, heaters, and irrigation systems, greatly enhancing your greenhouse’s overall functionality and efficiency. 2
Planning For Size And Layout
Planning a greenhouse on your property means checking the space’s availability and observing the area in your backyard or garden site. Consider any potential barriers like trees or tall structures that may not just be in the way but may also overhang your hothouse, effectively blocking the sun. Measure the space accurately so your greenhouse fits comfortably without hindering other outdoor family activities.
Also, think about your future needs. If your plants do well and you want to enlarge your operation, consider a potential expansion inside your greenhouse. Creating extra space for supplemental plants and new varieties may require additional equipment to help trap more heat inside. Remember, any expansion enables you to fulfill your gardening aspirations by cultivating your plants year-round. 3
Selecting The Right Design
Heating your greenhouse depends on your ability to plan and choose the right greenhouse design. Several excellent greenhouse designs remain popular among growers, including:
- Traditional Glass Greenhouse
- Polycarbonate Greenhouse
- Film And Fabric Structures
Let’s take a closer look at each of these options.
Traditional Glass Greenhouse
When most people think of a greenhouse, they likely picture one with glass and metal or plastic supports. These traditional greenhouses provide tremendous light transmission, which is the rate of sunlight allowed to pass through the glass. Because of this, classic greenhouses allow your foliage to receive the entire light spectrum they require to grow appropriately.
However, glass can be heavier and more expensive than other materials, not to mention more fragile. Today, traditional glass greenhouses are being replaced with hybrids, plastics, or other alternatives listed below. Regardless of which option you choose, regularly cleaning your greenhouse on winter days is essential to maintain transparency and maximize light exposure.
Polycarbonate is a lightweight and highly impact-resistant material that has gained popularity in modern greenhouses. While providing an alternative to glass houses, polycarbonate offers good insulation properties, is a great way to distribute sunlight, and reduces the risk of burned plants. 4
Film And Fabric Structures
Film and fabric are cost-effective options for smaller or temporary winter greenhouses. Their durability isn’t as long-lasting or durable as glass or polycarbonate options mentioned above, but they can still provide a suitable and affordable environment for seasonal plant cultivation.
Selecting The Best Winter Cold Plants
During winter, greenhouses help absorb heat and keep plants warm. At night, however, they are cooler as the outside temperature drops. Therefore, it’s essential to grow greenhouse plants over winter that can tolerate some direct heat from the sun yet can tolerate light frosts, including:
- Leafy Greens
- Root Vegetables
- Winter Blooming Shrubs
- Berries And Colorful Stems
- Pansies And Violas
Cold-hardy greens like kale, spinach, Swiss chard, and collard greens make excellent greenhouse selections. These vegetables can tolerate light frosts that may improve their flavor after exposure and pack plenty of essential nutrients. As long as temperatures stay relatively consistent in your greenhouse, these leafy greens can be harvested throughout the winter, providing a healthy and delicious supply of vegetables. 5
Consider planting root vegetables like carrots, beets, turnips, parsnips, and radishes in your grow house. Like leafy greens, these hardy veggies can withstand light frosts and develop sweeter flavors because of them.
Some herbs are surprisingly cold-tolerant and do fine even when temperatures drop. Examples include rosemary, thyme, sage, and savory. These herbs add flavor to your dishes and offer a lovely smell that you can use for teas or infused oils, perfect for the coldest months of the year. 6
Winter Blooming Shrubs
Choose shrubs that produce colorful flowers during the winter months, such as jasmine, camellia, witch hazel, and viburnum. These flowering plants provide cheerful colors and delightful fragrances while uplifting your mood and being an aesthetic addition to your greenhouse.
Berries And Colorful Stems
Plants with colorful berries or stems add beauty and intrigue to your greenhouse. Winterberry, roses, ornamental brambles, dogwood, and red-twigged or yellow-twigged dogwood varieties offer bright berries or vibrant stems that add a splash of color against a winter backdrop.
Pansies And Violas
Pansies and violas are cold-tolerant annuals that can bring pops of color to your winter greenhouse. These charming flowers come in different shades and are known for their flexibility in chilly temperatures. Plant them in containers or flower beds within your greenhouse for a bright and cheerful display.
Look for a greenhouse with proper insulation to prevent wild temperature fluctuations. Good insulation options include double-layered walls, insulated glazing, foam panels, or affordable and easily attainable bubble wrap. Insulation helps reduce energy consumption, protects plants from extreme weather conditions, and keeps plants alive.
Keeping your plants comfortable over winter is crucial for greenhouse gardening. The video below explains some of the most affordable ways to insulate your greenhouse. Remember, because plants have different growing habits, whether you’re cultivating vegetables, a tropical garden, or anything in-between, you’ll want to ensure each greenhouse plant enjoys the environment and warmth you provide. 7
A heater is one of the most practical ways to heat a greenhouse to avoid risking the health of your plants at night. Options like radiant heating, forced-air systems, or electric heaters can provide the necessary warmth for your plants over winter. One of the best and inexpensive ways to heat your greenhouse over winter is to make a heat sink.
Adding A Thermal Mass (Heat Sink) To Your Greenhouse
Placing water containers in the greenhouse is widely used to create thermal mass. In smaller hothouses, you can strategically position one-gallon plastic jugs filled three-quarters full of water among your plants. During the day, the water warms and as temperatures drop, the warm water continues heating throughout your greenhouse. For extra warmth, consider painting your plastic jugs black.
Watering And Irrigation
To effectively water your greenhouse crops, continually monitor the soil moisture levels. While most plants enjoy cool and slightly moist soil, adjust watering frequency based on plant needs and climate conditions.
Just as during the warmer summer months, proper watering is essential for winter gardening. Although your greenhouse should offer some protection from the outdoor elements, you’ll want to monitor moisture levels to avoid dryness or overwatering.
One quick way to perform a soil moisture test is by inserting your finger into the soil, approximately 1-2 inches deep, being careful not to penetrate your plant’s root zone. If the dirt feels dry at that depth, it indicates that watering is needed. 9
Tips For Successful Winter Greenhouse Gardening
Here’s an excellent step-by-step plan for creating a prosperous home greenhouse oasis.
- Choose affordability. When building a winter greenhouse, opting for inexpensive materials can be cost-effective. One such option is investing in a kit or portable house that facilitates simple-to-use instructions yet provides durable construction.
- Compost. If your greenhouse is large enough, consider placing an enclosed compost tumbler in the middle of your hothouse overnight as temperatures drop. You’ll protect your compost from the elements while providing your crops an extra layer of warmth. To avoid any pungent odors, you’ll want to ensure your compost has a balanced ratio of greens to browns. Most tumblers come with wheels, so moving it in or out of your hothouse at night is simple. 10
- Hydrate your foliage. During winter cold spells, and as long as your greenhouse temperature remains moderate, watering your plants can create a protective barrier around their roots, minimizing the risk of frost damage. Moisture can also help control temperature fluctuations, providing a more stable environment your plants will appreciate.
- Let there be heat! Adjust your heater to 1500 watts, considering the severity of the cold weather conditions. If using a heat sink (thermal mass), ensure your water jugs are painted black and spread evenly around your greenhouse. 11
- Look at the forecast. If it is 10 degrees Celsius (50°F) or lower, leave the greenhouse door or flap closed to retain inside warmth. If the temperature rises above this threshold, leave the door open for optimal air circulation and to minimize the risk of plants bolting.
Extending your growing season with a greenhouse can be a viable and sustainable gardening practice unless you’re dealing with extreme arctic winter temperatures.
Whether you choose a traditional glass greenhouse, polycarbonate, or a cost-saving fabric option, you’ll want to select a location that receives the best amount of winter light, is easily accessible, and has sufficient protection from the elements.
Although you can grow various greenhouse veggies, some excellent options include leafy greens, root vegetables, herbs, and winter shrubs.
Lastly, offer your precious plants a comfortable environment to settle in over the winter months. Provide adequate insulation to provide heat throughout your greenhouse and spread nutrient-dense compost atop your soil to insulate your plant’s roots further.
And remember to water your foliage. Just because it’s cold outside doesn’t mean your plants don’t get thirsty. You’ll want to adopt a winter watering routine to keep your budding garden happy. By applying a bit of common gardening knowledge in your greenhouse, you can enjoy a fresh food supply that will last until the arrival of springtime.
Do you currently have a successful greenhouse operation? We’d love to know what vegetables and plants you choose to grow inside. Drop us a line below in the comments!