Updated at: 25-04-2022 - By: Sienna Lewis

Small winter greenhouses can be improved upon by watching what happens in the larger winter season. Be careful while planning a greenhouse, and be sure to put it on the east-west axis. This offers it the most time in the sun during the course of a single day.

Maintain a minimum of six hours of direct sunlight in the greenhouse during this time of year. If you intend to power your greenhouse with electricity, you’ll need to locate it near the source. Away from the area where children are playing is the best location for this.

Keep your working thermometer in your do-it-yourself greenhouse. Unless the system has automated vents, you’ll need to keep an eye on the temperature. The temperature in the winter must be just right so that the plants don’t overheat.

How Can You Build Your Greenhouse In The Winter

Thermal mass, or a heat sink, is a simple and inexpensive solution to keep your greenhouse warm throughout the winter. Items that may store heat throughout the day and release it at night are known as “heat traps.” This also tends to raise the temperature by around a degree or so, making the contrast even more pronounced.

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Follow these instructions to add thermal mass to the greenhouse and your own body. The greenhouse’s irrigation needs will be met thanks to the thermal mass. The water you use in your containers should be adequate to cover the entire greenhouse or plantation, even if it is a smaller building.

You may also make the greenhouse more heat-absorbing by painting it black. If you’re serious about doing your homework, you’ll find a slew of other benefits as well. To stay up to date on the latest developments in the field of gardening, peruse gardening periodicals.

Can You Grow In A Greenhouse During The Winter

Yes, it is possible to grow plants in a greenhouse even in the dead of winter. According to some, growth in a greenhouse can only occur in the summer when there is enough sunlight. However, you may take use of what the winter has to offer by cultivating your crops.

The Correct Way To Winterize Your Greenhouse

In most cases, the greenhouse may be prepared for the winter without too much difficulty. Winter growth planning is something that every greenhouse manager can do. To put it another way, this is your chance to get your greenhouse in tip-top form before the first snowfall by cleaning up the mess left over from the previous summer and the harvest season. This means you can remove organic matter from the greenhouse, clean the walls, and operate all of the greenhouse’s machinery.

Then, You Have To Select The Crops

Crop growth throughout the winter months must always be carefully planned in order to safeguard them from the harsh climate. These hardy root crops and leafy greens include your collards and carrots, as well as spinach and other types of greens, which may be grown year-round in the northern regions and snowy regions of the planet in order to ensure the highest results in winter.

Managing Humidity

Making a modest winter greenhouse necessitates a thorough understanding of the process. The colder the weather outside the greenhouse, the more energy is needed to keep the structure warm. The sun’s heat may not be strong enough to keep crops arriving until spring, regardless of whether you’re in the south for mild winters or the north for brutal storms.

These are the reasons why you need to equip your home with heating vents that are effective and of the correct size in order to maintain the ideal humidity levels.

The remaining steps are as follows:

  • Improving the quality of light
  • Efficient harvesting

What Can Beginners Cultivate In The Greenhouse?

Winter is a terrific time to watch your plants grow from seedlings to mature plants that can be used in a variety of dishes.

Winter Lettuce

Designed for the salad fanatic, there is a kind of lettuce that is perfect for the cooler environments. To name a few, there’s the rocket, lamb’s lettuce, and the little gem lettuce. Considering how quickly they grow, it’s possible that you’ll need to harvest when the leaves are at their largest.

Brussel Sprouts

Brussel sprouts, whether you like them or not, are your best bet for winter greenhouse vegetables. In March, when they are just two inches in diameter and have taken three months to grow, the gardener should be able to harvest them.

If you plan to cook with the sprouts, you’ll want to harvest them in the same size range, which will allow them to take up more of the cooking time.

What Temperature Must A Greenhouse Be In The Winter?

On how to build a modest winter greenhouse, temperature is essential. As a result, the procedure will be complete.

A temperature of three degrees Celsius is required for a frost-free greenhouse with minimal heating. Citrus trees, fuchsias and other plants prefer temperatures of seven degrees Celsius or above, while pelargoniums and other flowering plants thrive around 10 degrees Celsius or lower.

Let the sunshine in

If the greenhouse was built by a competent contractor, it should already be situated in an area that is not obstructed by trees or other structures. Make sure the greenhouse receives as much sunshine as possible, especially if the sun’s course is lower in the sky.

Add thermal mass

The creation of a thermal mass or heat sink is one of the most straightforward and least expensive ways to warm greenhouses in the winter. These are items that store heat during the day and dissipate it at night when it’s cold outside. A couple of degrees is all it takes to make a big difference.

Containers of water can be used to create a thermal mass in a greenhouse. The plants in a smaller greenhouse can be watered from one-gallon plastic jugs that have been capped and filled three-quarters of the way. Black food coloring can be added to the water to boost heat absorption in jugs, or the water can be painted black.

The use of 55-gallon barrels painted black and filled with water for big regions can be a good option. Overnight, they will expel the stored energy.

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Use a germination mat

germination mats are ideal for clients who want to use their greenhouses in the winter to start seeds for spring plantings. Root-zone temperature is maintained at an optimal level by using these mats, which reduces production time and speeds up the growth of plants at the beginning of their life cycles.

Cover up

When it comes to providing extra warmth to plants during exceptionally cold nights, customers can go as complicated or basic as they desire. While tarps, horticultural fleece, row covers or sheeting can all be used to help keep moisture in, keep the coverings away from the plants and remove them during the day, since the humidity level can rise too high.

Create some compost

It’s a win-win situation for customers who already have a compost pile in the greenhouse, as relocating it there keeps it warmer while also shielding it from the weather. As the process of breaking down the materials accelerates, the greenhouse’s temperature rises. However, if you cannot position the pile in the center of the greenhouse, you can still keep the plants warm by putting it somewhere else in the greenhouse. Additionally, the homeowner will have a ready supply of black gold come spring.

If your customer doesn’t know much about composting or doesn’t like the concept of a compost pile in the centre of the greenhouse, this alternate heating method may not be perfect for them. It’s best to avoid this choice if your greenhouse is attached to your home, as it may attract mice and rats in the winter.

Add insulation

Bubble wrap serves a purpose other than preserving delicate parcels and entertaining those who are easily entertained; it also serves as a barrier. Wrapping the greenhouse in bubble wrap can help keep out cold air and prevent heat loss. If you can’t find horticultural bubble wrap insulation at a garden center, regular bubble wrap can be used in a pinch.

Install a heater

To keep greenhouses warm, heaters are obviously the most obvious solution. However, they can be expensive to run and the heat quickly dissipates when they’re turned off. If your client does not want to run extension cables to the greenhouse, there are greenhouse-specific space heaters and gas heaters. To ensure that the warm air is dispersed evenly, ceiling fans are a need.

You should always examine the wires and connections of an electric heater to make sure they are not old or damaged. A well-ventilated space is essential for regulating carbon monoxide levels and preventing it from becoming overheated during the colder months.

7 Heating Options for Your Greenhouse

To keep your greenhouse warm in the winter, you no longer need to rely on finite and environmentally damaging fossil fuels. Eco-friendly alternatives can be found in the following list, which can be used whether or not you are connected to the grid.

You may benefit from one or more of the selections below (or a combination of two or more of these choices). How to grow food year-round even in a frigid climate, and how to do so ethically.

1. Hotbeds (Heat from Composting Materials)

Making hotbeds is an easy and inexpensive approach to keep plants from freezing in a greenhouse.

Raised beds covered with layers of decaying straw and manure (or other organic matter) are topped with an even thinner layer of growing media (soil/compost) into which plants or seeds can be inserted. To put it simply, it is a compost pile that is used as a raised garden bed.

A complete guide on how to build a hotbed may be found here.

As with any compost heap, the building blocks of a hotbed are organic in nature. Green (nitrogenous) and brown (carbon-rich) elements should be used in equal proportions.

Making a Hotbed

Horse manure and straw are the traditional ingredients for a hotbed. This is how many Victorian and early twentieth-century greenhouse beds were constructed. However, horse excrement and straw aren’t required. The same effect and heat may be achieved by using a variety of biodegradable materials.

From the bottom up, hotbeds generate heat. Materials in the hotbed decompose, releasing energy into the surrounding air. A hotbed can serve as an alternative to more expensive ways of winter heating by producing mild, natural heat.

To complete the hotbed, you’ll need to top it over with a mixture of soil and compost. A 1:1 ratio works best for me. The ideal compost is made at home. Peat-free compost should be purchased if you don’t already have it. (The use of peat compost is bad for the environment.)

Temperatures should be maintained at 75 degrees F by using a 3:1 ratio of heat-producing material to growing media. As a result, your growing media should be between 20 and 30 centimeters deep.

Cover Your Hotbed to Retain More Heat

Plants will stay toasty and warm even in the coldest settings if you cover their hotbeds with cloches or row covers within your greenhouse. It’s possible to cover your hotbed in a variety of various ways. For instance, you may make use of:

  • An aged pane of glass in a window.
  • The term “hot box” refers to a glass cloche or “small greenhouse.”
  • Polycarbonate sheeting that has been recycled.
  • Row covers made of plastic or a small plastic polytunnel.

Material that would have otherwise gone to waste can often be repurposed.

2. Hot Water Heating

A hot water pipe heating system can also be used to gently warm your greenhouse beds from below. Grand nineteenth-century greenhouses had plenty of hot water heating equipment as well. The water, on the other hand, was typically heated by coal boilers in those days.

A few more environmentally friendly options for heating water for such a system have emerged in recent years, which is encouraging.

Solar water heating panels are the first choice. Structures that allow water to be heated by the sun are not solar panels, but rather solar collectors. The term “hydronic heating” refers to the same thing.

Make your own direct solar water heater here if you’d want to try your hand at a DIY project.

You can make a solar hot water heater at Reuk.co.uk.

Using composting systems to coil pipes and heat water is another option for those looking for a low-tech approach to water heating. The decaying materials provide heat in any compost heap, including the hotbed described above. Water pipes can also transfer heat and keep soil temperatures higher than they would be if they were run through a compost heap before being run into a polytunnel.

Solar water heating may be all that is needed in some situations. When used as a preheater, the solar water heater raises the temperature of the water before it enters a boiler. If you want to learn more about the many types of boilers, keep reading.)

3. Ground To Air Heating

Another method of heating a greenhouse is to use pipes buried in the ground. It is possible to utilise the sun’s heat collected during the day in a greenhouse with a ground to air heat exchanger.

Warm, humid air is pumped out of the greenhouse through a system of pipes buried deep in the ground. An earth-based heat pump circulates heated air around the building at night through soil that acts as a “collector.”

The temperature in your greenhouse may be precisely controlled and maintained using the appropriate blowers and a thermostat.

Installing a greenhouse ground-source heat pump is another a possibility, albeit more expensive. (Also for your own residence, possibly.) To put it simply, this is a method of bringing heat energy from the ground up to grow areas that are coated in insulation.

4. Renewable Electricity Heating

It is possible to heat your polytunnel using renewable energy sources in a more conventional manner.

Installing solar panels is a common way to accomplish this. Small amounts of electricity, such as those required to run fans or pumps in the systems mentioned above, can be generated using solar panels. Another option is to power highly efficient greenhouse heaters.

Most greenhouses are better served by heating the soil beneath plants, rather than heating all of them. So, before looking into space heating options, consider piped subterranean heating.

An efficient electric boiler for such a system can be powered by renewable electricity (from sun, wind, or water).

Deep winter' greenhouse grows veggies year-round | MPR News

5. Wood-Fired/ Biomass Heating

Decomposing materials, as well as the sun, can be used to heat greenhouses with hot water pipes. However, a boiler can be employed if the above methods fail to heat the water to the desired temperature.

A boiler can be powered by renewable energy, as we’ve already explained. However, you can also use wood or other biomass to power a boiler in your greenhouse to heat it.

Old 55-gallon drums can be used to make a rustic DIY system, such as a wood-fired boiler. A combination of greenhouse heating and a solid-fuel stove in your home is a good idea if you can do it.

Make a rocket mass stove to heat your greenhouse using solid fuel. Fuel efficiency and heat retention are both achieved by using a rocket mass stove. Over the top of a stove-heated shelf, potted plants can be placed. Where the winters are particularly harsh, this is an excellent answer.

6. Rustic Heater With Candle and Plant Pot

The more elaborate heating systems described above may not be worth the effort if you simply have a small greenhouse.

It’s also a good idea to think of a simple remedy. You may make a mini space heater out of a ceramic plant pot and a candle by doing so.

If you’re going to use any kind of open flame, you’re going to have to follow all of the regular safety rules. A candle, on the other hand, can create enough heat to keep a tiny greenhouse from freezing.

7. Heating With Livestock

Think beyond the box when it comes to keeping your greenhouse plants warm throughout the cold months. A nice concept for winter gardening is to keep chickens in one part of the greenhouse (or in an adjacent coop) while cultivating plants in another.

The heat emitted by chickens’ bodies and feces can build up. The greenhouse temperature may be raised by a surprising amount at night using this method. As a result, the chickens will also benefit from the greenhouse’s ability to capture heat from the sun during daylight hours.

You can even cultivate plants in one portion of a greenhouse and keep cattle in another. When it comes to keeping greenhouse plants warm at night, animals’ body heat can play an important role.

Do You Need To Heat Your Greenhouse?

Some new ideas for heating your greenhouse in the winter have been discussed. Consider whether or not you need to heat your greenhouse before deciding on a heating scheme.

The current state of your greenhouse may already be adequate to provide the necessary protection during the winter months without the need to increase the temperatures. There may be no need for additional heating after all, if you follow the methods listed below.

Choose Hardy Plants To Grow Over the Winter Months

First and foremost, ask yourself: Are you attempting to grow the appropriate plants? I Consider which plants would thrive in an unheated greenhouse based on your temperature zone and the specifics of your polytunnel or greenhouse. In some regions, you’ll be able to choose from a wide range of choices. You’ll have fewer options in colder places, but there may still be some.

Remember to select plants and varietals that are best suited to your climate and locality, not just plant kinds. To the greatest extent possible, buy seeds and plants that are grown in your own backyard. Local gardeners can help you choose the best greenhouse-grown varietals to grow in.

Add Thermal Mass To Regulate the Temperature

It’s critical to consider how to capture the heat currently present in the system before implementing any heating systems. Enhance the thermal mass of your greenhouse.

During the day, materials with high thermal mass absorb and store solar heat energy, and at night, they slowly release it when temperatures drop. This natural energy flow can be refined and controlled via ground-to-air heating, as mentioned in the previous paragraph. If you want to get the same effect in a smaller amount, there are simple and quick techniques to do so

Some examples of high-thermal-mass materials are

  • Earth/soil/clay
  • Stone
  • Water
  • Bricks/ceramic materials

We can capture and store more energy and better control the temperature in a greenhouse by adding more of these materials. Adding extra thermal mass will help maintain a cooler temperature in the summer and raise it in the winter.

Adding thermal mass to a greenhouse can help prevent the need for heating in the winter, so here are a few ideas:

  • If you don’t currently have a greenhouse, think about getting an earth-sheltered one instead.
  • Your greenhouse should be filled with barrels or other containers of water.
  • Build walkways and bed edging out of materials that are highly thermally conductors. Bed edging made of stones, bricks, wine bottles filled with water, cob/adobe, or earth bags can also be used….

We can capture and store more energy and better control the temperature in a greenhouse by adding more of these materials. Adding extra thermal mass will help maintain a cooler temperature in the summer and raise it in the winter.

Adding thermal mass to a greenhouse can help prevent the need for heating in the winter, so here are a few ideas:

  • If you don’t currently have a greenhouse, think about getting an earth-sheltered one instead.
  • Your greenhouse should be filled with barrels or other containers of water.
  • Build walkways and bed edging out of materials that are highly thermally conductors. Bed edging made of stones, bricks, wine bottles filled with water, cob/adobe, or earth bags can also be used….

It’s possible to insulate individual plants even if you don’t have the time or finances to construct a double-skinned greenhouse in time for winter. It’s possible, for instance:

  • To protect individual plants, use miniature cloches (plastic drinks bottles, old milk containers, etc.) in the form of cloches.
  • Protect each plant by covering it with horticultural fleece (or upcycle old clothing or textiles for the purpose).
  • Extra shelter from the cold can be found in the form of row covers or mini-polytunnels placed inside the greenhouse.

Add Mulches to Protect Plant Roots

Mulches can also be used to protect the roots of plants throughout the winter. By covering the soil with a thick layer of mulch or ground cover, you can reduce the need for additional heating.

Root crops and alliums may be able to effectively overwinter in colder areas without the need to heat a greenhouse, for example

Examples of mulches that could be used for this purpose include straw, bracken, and wool from sheep. The following is a comprehensive list of possible garden mulches.

Deep winter' greenhouse grows veggies year-round | MPR News

When you’re deciding whether or not you need to heat your greenhouse in winter, think about heat energy. This can help you make the greatest long-term decisions, both for yourself and for future generations, both now and in the future.


In order to create a modest winter greenhouse, you’ll need to utilize bubble wrap to insulate your crops, invest in heating systems, use and apply a thermostat, and more. It’s easy to do this consistently and successfully.