How Does A Greenhouse Function?

A greenhouse is a structure made of transparent materials like glass, plastic, or cattle panel that collects heat in the form of sunlight. The glass traps heat by breaking up infrared electromagnetic waves into different waves that are absorbed by plants inside the structure. To be effective, a greenhouse needs insulation (and sometimes heating during the icy grip of winter), as well as ventilation and cooling.

Greenhouses can help increase plant growth and fruit production, and even allow you to grow plants that wouldn’t normally survive in your climate. Understanding how the process works can help you understand why greenhouses are so effective and how they use the “greenhouse effect” to hold their temperature so well.

A greenhouse should be placed on an east-west axis to get the most light, especially in winter. The primary purpose of greenhouses is to extend the growing season and improve crop yields by controlling the internal environment. Glass or plastic sheeting allows light rays from the sun to enter the structure, where they are absorbed by the plants and converted to heat. When the plants release the heat energy, it is trapped by the glass, keeping the greenhouse warm.

To be truly effective, a greenhouse needs insulation, heating during the icy grip of winter, as well as ventilation and cooling. Good greenhouse ventilation is crucial, as plants can get too hot even during cold or cool weather.

How do greenhouses stay warm?

Greenhouses provide a sheltered environment for plants by using solar radiation to trap heat. This system of heating and circulating air creates an artificial environment that can sustain plants in cold or variable outdoor temperatures. Heat enters the greenhouse through glass or plastic, warming objects, soil, and plants inside. The warmed air near the soil rises and is replaced by cooler surrounding air, creating a warmer microclimate. In temperate climates, the sun may do all the heating, but in colder climates, artificial heat may be necessary.

Some greenhouses have access to central heat from the main building, while others rely on natural or bottled gas, heating coils, or fans. Other energy sources like solar batteries or animals are being explored as heat is a significant expense. The sun’s energy can easily travel through greenhouse glass, but the radiation emitted by plants and soil helps trap heat inside.

What is needed to operate a greenhouse?

A greenhouse should have a headhouse with a work area, receiving and shipping area, utility room, office, and employee room. It should be built high enough for overhead storage and have adequate water, electricity, and telephone for expansion. Concrete floors are recommended for cleanliness and access, and adequate drainage is essential. Production can be on the floor or on benches, with fixed peninsula benches or movable bench systems being used for increased space.

Carts or overhead trolley conveyors can reduce materials handling costs. Germination rooms should be separate from benches, with good heat control and a fog system for an ideal environment. Lighting can help seedlings germinate. For heating, a hot water boiler is the best choice, with independent temperature control for different crop needs. Hot air furnaces or unit heaters are suitable for winter shutdowns, as water systems need to be drained.

What do you need to make a greenhouse work?

In this podcast, Sheri George, a lifetime master gardener, discusses greenhouse gardening with a focus on essential items such as ventilation, temperature monitors, heat mats, electricity, shade cloth, and precautions. Sheri began her greenhouse gardening journey in Colorado, where her outdoor garden struggled in high winds and extreme temperatures. Her husband, Lee, gifted her a greenhouse kit as a Christmas gift, providing a controlled environment for growing tomatoes and other vegetables that struggled in harsh Colorado conditions.

Sheri’s experience in greenhouse gardening has given her a unique perspective on what to know before and after buying a greenhouse. Sheri’s Atlanta, Georgia-area greenhouse was first visited in 2011 for an episode of Growing a Greener World®. Sheri’s greenhouse provides a controlled environment for gardening enthusiasts to grow their favorite plants in a controlled environment.

How does a greenhouse work?

Greenhouses work by allowing sunlight to enter and trap thermal energy, keeping the air and objects inside warm throughout the day. The transparent walls and roof allow visible rays of sunlight to pass through, heating up the air and objects. The glass acts as an insulator, locking in heat and keeping the temperature stable. Matter within the greenhouse, like soil and water, absorbs thermal energy from sunlight and releases it slowly, keeping the greenhouse warm even after the sun sets.

If the greenhouse contains high iron content, it can regulate temperature with gradual heating and cooling throughout the day. As a closed structure, there is no breeze dispersing warm air, ensuring the temperature remains constant and warmer than the cold snaps outside.

What does a greenhouse need inside?

The greenhouse is a crucial part of any indoor growing adventure, and it’s essential to consider various aspects such as lighting, temperature and humidity control, watering, sanitation, and bench types. Some greenhouse hobbyists prefer using biodegradable pots and store them in water-tight containers. Growing mediums can be mixed in buckets with lids in small greenhouses or stored in large plastic tubs with lids in larger greenhouses. Benches are also essential for keeping plants off the ground and should be painted with semi-gloss paint to protect against mold.

Sanitation is vital in a greenhouse, as it prevents the growth of fungus, bacteria, or bugs. Bleach and disinfectant spray are essential, along with sinks and large washing tubs. Irrigation and drainage are also crucial, with benches designed with holes or slats to allow water to drip through. Ventilation is essential, with some greenhouses requiring vents to release built-up heat and humidity in the summer.

Artificial lighting is necessary for proper lighting, and fluorescent lights can be used if plants need longer days or are not naturally lit. Shades are also important for shade-loving plants, and shade cloths help keep the hottest rays out of the building.

Climate control is essential for greenhouses, with heaters and fans being cost-effective options for small spaces. It’s essential to use thermometers and hygrometers with a climate control system for precise control. By understanding these basic greenhouse necessities, you’ll be well on your way to enjoying the gardening season all year long.

What equipment is needed to build a greenhouse?

In order to ensure optimal plant growth within a greenhouse setting, it is recommended that consideration be given to the installation of heating and cooling systems, in addition to other materials such as shelves, plant stands, watering systems, and grow lights, in accordance with the prevailing climatic conditions.

Do greenhouses need heat?

Greenhouse hobbyists often need to add a heating system to keep their greenhouse operational year-round. The three most common ways to heat a greenhouse are gas, electric, and passive solar heat. Gas heating is the least expensive option, but open flame heaters can cause issues for budding plants and have safety oxygen sensors that automatically turn off when depleted oxygen levels occur. Gas heaters with a flu and power exhaust are best for greenhouse applications, as they require a hole punched into the side of the greenhouse for the exhaust.

Electric heating is the most efficient, running at 100 efficiency due to the lack of ventilation. However, it is expensive and may not be feasible for many gardeners’ budgets. To offset some of the cost, passive solar heat can be used. If choosing an electric heater, it is best to get a 240V unit with plenty of heat capacity, as they save money and are reliable over the long run. If using a 120V unit, avoid infrared heaters or heaters that transfer heat to objects instead of heating the air.

For greenhouse applications, a heater that heats the air within the greenhouse is necessary. Oil-filled radiator-style heaters are the best inexpensive 120V heaters for greenhouses, which can adequately heat small hobby greenhouses during winter months when placed near a fan.

In summary, greenhouse hobbyists need to consider both gas and electric heating systems to maintain their greenhouses year-round. Gas heating is the most cost-effective option, while electric heating offers more efficiency and reliability.

What are the conditions for a greenhouse?

Plants thrive at temperatures between 18-24°C and relative humidity between 40-80%. To ensure a rich harvest, fertilize, water regularly, and use Ruuvi sensors to monitor greenhouse conditions. This will allow you to start growing crops in early spring and collect harvests into autumn.

Transfer tomato seedlings to the greenhouse when the temperature doesn’t fall below 15°C at night and cucumbers when it remains above 18°C. The temperature should be lower at night and higher in the day, with a temperature not exceeding 26°C. Temperature monitoring is also crucial during winter if plants have been moved to the greenhouse for overwintering. By following these tips, you can maximize your greenhouse’s potential and ensure a successful harvest.

Do greenhouses work in cold climates?

To use a greenhouse in winter, add heat through passive solar heating or electric heaters. Polycarbonate panels are natural heat insulators that can retain heat at a higher rate than other materials like glass. Look for a 4-wall construction on the roof and window panels for better heat retention. This allows for an extra few weeks in spring and fall without adding heat, saving money and plants.

For a greenhouse that requires little exterior maintenance, choose a rot-resistant material. Wood greenhouses may blend in with the aesthetics of a backyard, but they should not start to rot during the first rain or snow. By choosing a greenhouse that effectively retains heat, you can save money and ensure the health of your plants.

How do greenhouses not overheat?

Proper air circulation and ventilation are crucial in greenhouses, providing fresh air to plants and controlling temperature and humidity. Growing Spaces designs automated vents and fans to ensure reliable ventilation. An example of a 110-volt fan in a 33-foot Growing Dome moves air, while direct drive cooling fans run from solar panels cool the greenhouse. An extra solar-powered exhaust fan can be upgraded with any Growing Dome greenhouse kit, which includes a 12″ endless breeze fan, thermostat, shutter, uni-vent piston, solar panel, exterior hood, and hardware.

What is the requirement of greenhouse?

The greenhouse should be thoroughly ventilated to control temperature, ensuring it doesn’t exceed 2°C throughout the year. Alternative methods of heating and cooling include sprinklers of hot and cold water, earth tunnels for summer and winter cooling, trench construction for winter heating, and circulating borewell water in pipes. Heating greenhouses in cold climates like North India or the Himalayan Region at high altitudes is recommended for better produce. Double glazing with an air cushion can significantly reduce heating load. Overall, proper ventilation and a combination of these methods can help maintain optimal greenhouse conditions.