Greenhouse is a way of making an optimal climate inside a glasshouse for the delicate plants of a cooler climate. To use this greenhouse proficiently, heating it is fundamental when your plants are at risk of being frost.
This guide presents some helpful and practical tips for heating your greenhouse to get a suitable environment for the plants.
Thermal mass, insulation, compost pile, coverings are natural heating systems that directly depend on solar energy. They don’t cost you much and easy to arrange. Some other is fuel-consuming and makes environmental issues but produces much heat with less effort.
Whatever system you follow, be watchful on controlling heat circulation in a way that meets the need of your tender plants and doesn’t harm them. Ventilation and installing a thermostat would assist you to keep the temperature steady: not to chill or overheat your foliage.
How to heat a greenhouse
A variety of heating systems is available for a greenhouse. Here are some practical tips for heating your greenhouse in an efficient way that might help you a lot.
1. Add thermal mass
This greenhouse in Colorado, built by Smart Greenhouses LLC, has large water barrels along its back wall to collect, store, and distribute heat.
Photo by Smart Greenhouses LLC
Thermal mass is the best option for heating the greenhouse naturally. It is something like placing the objects inside the greenhouse that absorb heat in the day time and slowly release it at night when the temperature goes down.
You can choose several one-gallon plastic containers filled with water and put them randomly with a minimum interval. But these wouldn’t work in a hefty greenhouse. 55- Gallons of metal drums filled with water are popular thermal mass for larger greenhouse. Try to put them where they are direct in sunlight, especially at the northern wall of the greenhouse.
Any dense material like stones, cement, and sand will do, but water retains 2 times as much heat as them. Don’t forget to paint the containers or drums black to store maximum heat.
2. Add insulation
Insulation saves your greenhouse from losing its stored heat in the prevailing winter wind. Bubble wrap would make this insulation easier. These wrap block winter drafts and thus control the flow of wind and diminish heat loss.
Although regular wrap can do the job in a pinch, horticultural bubble wrap can withstand UV and insulate better with its larger bubble. Attach a layer of bubble wrap to the wall and fix them with tape or peg.
3. Make a compost pile
Compost has another crucial purpose rather than being very essential nutrients for plants. The compost pile acts as a natural heater and surprisingly a larger compost pile produces 100-160 degree temperature which is quite enough to heat up an oversize greenhouse. Organic materials of compost break down by the magical aerobic bacteria contained in it and it releases heat while decomposing.
You should build a compost pile in the middle of a greenhouse so that it can provide heat all over. If you think it looks odd or disturbs you in moving, places it otherwise.
A huge compost pile that can maintain above 100-degree temperature can’t be placed inside the greenhouse. Place it nearby as it should be physically connected to the greenhouse. This heater relies on a heat exchanger where water flows through a channel set inside the pile. This water gets heated while passing and then circulate through the greenhouse and emits heat.
4. Plant Covers
Covering plants with one or two layers of horticultural fleece, on a frigid night, give them extra degrees of protection from cold winter. Tarps, row covers, sheets, and greenhouse cloche are some more coverings that help plants grow in the greenhouse.
But this is your every morning task to remove them as your tender foliages don’t overheat and humidity level remains steady.
5. Heating through combustion
Woodstove is a simple way to get the most heat from the lowest cost. Hot air directly coming out of a chimney heats up your greenhouse which is adjacent to the chimney. Yet, it’s quite a laborious task to haul wood every day and not everyone has access to sufficient wood. Moreover, you have to be likely to fire several times a day to keep it burning.
Rocket mass heater
Rocket mass heater is much more resourceful than a conventional wood stove. Wood burns in a high-heated combustion chamber connected to large bricks or stones. The thermal mass gets heated by the time and releases warmth towards the greenhouse.
6. Electric heater with fan and thermostat
Air circulation becomes a great problem inside the greenhouse, especially during the very cold parts of the year. Frost and moist collected on plants wouldn’t fade away in a humid atmosphere of a greenhouse. Without air circulation, the temperature wouldn’t spread evenly making some foliage prone to cold wind and some other to overheating.
An electric heater with fans is a trouble-free way to keep air circulation even when you close every vent uptight on a chilly night.
Some heaters come with a thermostat that turns on automatically when the temperature goes down and turns off if the greenhouse is overheated or sometimes the heater tilts over.
7. Heat only where it is necessary
Heating the whole greenhouse is a bad idea. It is time-consuming and costly to your pocket too. Some weeks and delicate plants prone to cold wind air need extra temperature. Separate those by raising bubble wrap curtains to treat them with suitable heating systems. It will save your money and time.
8. Don’t forget to ventilate
High humidity is not good for the health of your foliage as it spreads fungal diseases. So, open the vents on the day time when it’s sunny to get rid of condensation.
Besides, in summer, ventilation prevents greenhouse from overheating allowing light dry air to come in replacing warm humid air.
In winter, ventilation is very important to prevent cold drafts from coming inside through the escapes.
9. Incorporate a heat exchanger
Heat exchanger is a very well efficient upgrade of thermal mass. Here the huge amount of soil beneath the greenhouse works itself as a mass which is also called climate battery or ground to the air heat exchanger. With variations in design, one mechanism is common here: transmit of heat and storage is balanced at the same rate.
This heater circulates heat through a set-up of several layers of tube laid 2-4’underneath the ground. When the temperature heats up, a fan pumps hot air from inside the greenhouse through the network of tubes. As the temperature drops, the moist in air vapors and condenses. At the same time, the energy released in this process heats up the soil. Accordingly, this soil mass becomes a huge storage battery and is several times more capable than many larger water barrels or other big thermal mass.
Again here, a thermostat would kicks on or off the fan according to the fall or rise of temperature.
10. Don’t cook your tender plants
After all the discussions above, it is worth mentioning that you have to be on the lookout against making any mistake while heating up that causes your tender plants to be cooked.
When you are using any thermal mass, make sure that the ventilation system is properly balanced. You can rely on a digital vent available these days to lessen your effort to ventilate the greenhouse manually.
Set temperature to the optimal level that is enough to make your greenhouse frost-free and to heat up well balanced. A thermostat will make this job easy for you.
While using a heater, place it rightly at a distance so that flow of warm air doesn’t burn your delicate foliage.
Before deciding on the heating system you are going to install in your greenhouse, determine the space to be heated and the extent of warmth needed for your climate. Choose the right system for you. Avoid the time and labor-consuming system if you can’t manage. Go for automated systems (like underground heat exchanger) that are quite comfortable, though pricey on your side, makes your gardening easier.