Everything you need to know about greenhouse temperature and light

Greenhouses are an integral part of horticulture, allowing plants to grow in a controlled environment and achieve peak productivity regardless of outside weather conditions. In this article, we will discuss the main aspects of greenhouse temperature, ventilation, heating and lighting, which are necessary to ensure optimal conditions for plants. Understanding the importance and functions of each of these elements will help you better plan and implement effective greenhouse climate management strategies. We will also move on to heating techniques which are vital during winter and cold nights, and look at the importance of lighting for plant photosynthesis, as well as the use of modern timers to help regulate the amount of light, saving energy and extending the life of lighting equipment.

Temperature

When it comes to temperature, the goal in a greenhouse is to maintain the optimum temperature for the plants being cared for inside. Monitoring day and night temperatures will help determine which heating methods work best and which types of plants should be planted depending on the climate of the greenhouse. The three most common greenhouse environmental control devices are:

The thermostat automatically regulates the heating system according to the set temperature.

• Mechanical thermostat : Although not as accurate as a digital thermostat, a simple mechanical thermostat can be used to operate heating and ventilation equipment.
• Digital thermostat : Multi-stage digital thermostats can be used. They can control multiple heating and ventilation devices. Once the desired temperature is selected, the system will turn the cooling or heating equipment on and off, thus maintaining the optimal temperature at the appropriate time.
• Computer controlled systems : can be used in conjunction with environmental sensors to control all aspects of heating and cooling. Carbon dioxide (CO2) levels in the greenhouse can also be monitored and adjusted accordingly.

Ventilation and cooling

Since the main purpose of greenhouses is to collect as much heat as possible from the sun, they can overheat in hotter weather. Overheating can affect or completely kill plants. Sometimes just opening the doors and windows and natural ventilation helps to control the temperature and humidity of the greenhouse. However, this method can attract pests and diseases to the greenhouse.

The HAF type fan is used in an industrial greenhouse.

Electric fans are useful for increasing air flow and cooling the greenhouse. Horizontal Air Flow Fans (HAF) are used to circulate air inside the greenhouse. They will help distribute heat evenly and reduce condensation on plant leaves, which can cause disease. In larger greenhouses, fans mounted on the ends of the greenhouse can be used. They are large enough to exchange all the air in the greenhouse with the outside air.

Shade netting is used to reduce the intensity of sunlight.

If you don't want to invest in fans, you can choose a non-electric option - a shadow network. It is a woven material that can be used to cover the inner parts of the greenhouse, thus providing a cooling shade. The shade cloth is available in different densities, thus perfectly adapting to the respective greenhouse cover and amount of sunlight.

Heating

Although greenhouse covering materials are efficient conversion agents for converting sunlight into heat, they also release a lot of heat to the outside because they are not particularly good thermal insulators. Depending on your location, this can cause problems with maintenance and maintaining a constant climate when the sun isn't shining and it's cold outside.

Circulating hydraulic heating system is designed to warm the ground.

Greenhouse heating can provide plants with the warmth they need during cold periods when outside temperatures are lower. For greenhouses, heat can be supplied through electric hot air heaters with fans (commonly used), heat radiating hydraulic (based on water circulation) systems. These systems are installed on the ground or on growing beds. Having a compost bin in the greenhouse will help with maintaining the temperature during colder periods.

The water tanks in the greenhouse are designed to maintain a higher temperature at night.

In order to maintain a higher temperature in the greenhouse during the summer, various water containers filled with water can be used. The water heats up during the day, and when it cools down at night, it radiates heat into the air, thus maintaining a higher temperature in the greenhouse. It is recommended to paint the water tanks black, so that they collect the maximum possible amount of heat during the day. The GRAAS iRigator continuously measures the temperature of the greenhouse, so it is even easier to track, understand and regulate the climate of the greenhouse with the GRAAS automatic watering system.

Lighting

All plants need light for photosynthesis, the plant's process that converts light, oxygen, and water into carbohydrates (energy). Plants need this energy to grow, flower and produce seeds. Greenhouses are designed so that plants receive as much natural light as possible. The more light the plant receives, the better the yield. However, plants can suffer if the light is too intense, too little, or if the light is too short.

When the amount of natural light during the day is low, supplemental lighting can help plants get the right amount of light. Additional lighting provides an opportunity to control the quality and intensity of light. This is especially useful for shorter days in spring or autumn, or in cloudy weather. In addition, as the amount of daylight changes over time, the needs of plants also change.

Full-spectrum LED lamps are used for seedlings before the plants are transferred to the greenhouse.

Using an automatic lighting timer can help ensure that plants are getting the right amount of light. Such timers can be useful in the early morning and evening, at sunset or after sunset. In addition, automatic timers save energy and extend the life of bulbs.

Various light bulbs are used for lighting. They are chosen according to need and budget, respectively. We review the most commonly used types of bulbs in more detail in this article .

In summary

Thus, in order to ensure an ideal greenhouse climate and to create ideal conditions for plant growth, the following facts should be taken into account:

1. Ventilation and cooling : necessary methods of greenhouse temperature and humidity control. Natural ventilation is the simplest method, but can bring pests and diseases, so it is worth considering the use of mechanical fans, shade nets, or automated systems to help reduce the risk of overheating and ensure optimal conditions for plants.

2. Heating : Greenhouses lose a lot of heat, so additional heating may be needed during the cold season. Greenhouse heating can be various: electric heaters, hydraulic systems or even the use of compost. It is also useful to use water tanks that store heat during the day and release it at night.

3. Lighting : Plants need light for photosynthesis, and greenhouses are designed to maximize the use and transmission of natural light. However, with insufficient sunlight, additional artificial lighting is necessary. Automatic lighting timers are an efficient way to ensure a consistent and economical light supply.

The combined use of these tools helps optimize the greenhouse environment, ensure plant health and productivity, and use resources efficiently.