Growers invest large amounts of capital in their greenhouses, equipment and even automation to create efficient and profitable growth. A business can have the most high-tech equipment money can buy. However, if the business neglects the lighting, the growth may stop and money losses are experienced with the energy and operation expenses in addition to the unhealthy product.
For businesses that produce with light in agricultural production, lighting is an integral part of the business, and the lights should be configured equally and perfectly throughout the greenhouse in the most effective and efficient way possible.
When designing a lighting plan, there are many important factors to consider such as Light intensity, plant requirements, greenhouse layout, greenhouse coating. Since each of these elements affects the lighting provided inside the greenhouse, all these factors need to be considered for a healthy lighting plan.
A comprehensive greenhouse lighting plan must take into account such things as crop needs, greenhouse layout and light intensity to ensure uniform and even light distribution over all plants for healthy and thriving growth.
Before getting into lighting plans in agricultural production, it is important for growers to know the lighting options they have and to choose the best one for their crops and greenhouses.
There are 4 types of lighting commonly used in greenhouses.
LED luminaires are the longest lasting and most energy efficient greenhouse lighting option. Although investment costs are more expensive than other lighting options, it provides a return to its investors with the energy savings they provide. LEDs have a lifespan of about 50,000 hours, high end models even provide a spectrum of colors.
“A lighting plan should be designed by a greenhouse specialist with specific greenhouse lighting experience.” - Janine Coppola
High-pressure sodium or HPS luminaires are a type of high-intensity discharge (HID) lighting, giving a bright and intense light to crops.
These luminaires are an efficient and popular choice among greenhouse growers as well as providing a good spectrum of light to the plants.
Metal halide fixtures, another form of HID lighting, are similar to HPS fixtures. The light of these luminaires, which provides blue or white spectrum illumination with an intensity similar to HPS luminaires, is very suitable for vegetative growth. These lights are ideal for places that lack natural light.
T5 fixtures are more efficient and compact than their more traditional, legacy fluorescent counterparts. These full spectrum luminaires are ideal for greenhouses that do not receive natural sunlight and are beneficial for large areas due to their efficiency. They also work well for reproduction.
Growers need to consider the light spectrum their crops need when choosing lighting fixtures and designing lighting plans. The spectrum of light required for growth varies from crop to crop, and different lights produce different color spectra.
For example, a lettuce grower may prefer metal halide luminaires for lighting; because its product is not a flowering crop like a tomato.
On the other hand, producers growing blooming plants such as tomatoes will need high-pressure sodium or full-spectrum LED fixtures. Since the color spectrum of the final LEDs can be adjusted or changed according to the growth stage of the products, it works better than other products in smart lighting applications. The light intensity in these LEDs can be dimmed for various stages of growth.
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Once the lighting is selected, it's time for growers to create their greenhouse lighting plans. It is important to note that a lighting plan must be designed by a greenhouse specialist with specific greenhouse lighting experience.
Here are 3 factors to take into account!
There are many factors to consider when designing a greenhouse lighting plan. Adrian Valois , greenhouse specialist at GrowSpan Greenhouse Structures, touches on three important considerations growers should keep in mind when creating their lighting plans.
“The first thing to think about is your crop. Different crops have very specific needs when it comes to the right spectrum of light they need to thrive,” says Adrian Valois.
“Second, you need to have a layout for your products so that you can maximize the output from each light fixture used.”
“Third, you need to have the right wattage and coverage for each light.”
The layout of the greenhouse has a great influence on the lighting scheme, so growers should try to maximize the yield of each light by having a good crop arrangement. For example, if crops could be grown in a 2x2-metre field instead of a 3x3-metre field, growers could have 25 plants instead of 10 under lighting.
Depending on how plants and equipment are placed throughout the greenhouse, lighting placement needs to be adjusted to reduce shadows and provide the crops with the maximum amount of uniform light in the most efficient and effective way possible.
The equipment around the greenhouse and even the lighting fixtures themselves can cast a shadow over the crops inside the greenhouse and limit the light received by the plants. If the lighting inside the greenhouse is not hung correctly, the beams can cast shadows on the plant.
Light intensity is very important when creating a lighting plan in agricultural production. Each plant needs different light intensity. Too high or too low light intensity can be harmful to each plant. Finding the perfect light levels and the right light coverage for plants will ensure plants thrive.
“Light intensity is more important than the number of luminaires. With the right light, fewer fixtures will be needed, providing greater coverage.” says Valois.
Another factor to consider is the heat emitted by lighting fixtures. Some crops can benefit from additional heat, which can save growers some savings on heating costs. Other crops may not need heat, especially if the greenhouse is already in a warmer environment. When designing lighting plans, growers should consider what temperatures their crops thrive at and how much heat their lighting choices emit.
Valois says, “lighting inside the greenhouse helps provide the heat the grower needs during the colder months.” says. Especially high pressure sodium and metal halide armatures will help reduce heating costs inside your greenhouse.
Different greenhouse covers have different light transmission rates. Therefore, growers should consider greenhouse cover materials when creating their lighting plans.
A greenhouse with a greenhouse cover with a low light transmission rate may need more lighting requirements than a greenhouse with a greenhouse cover with a higher light transmission rate. Growers should also consider the heat retention properties of greenhouse covers. Coverings with high heat holding capacity will keep the heat coming from the lighting inside the greenhouse and will make the inside of the greenhouse even warmer.
When creating a lighting plan, growers should look ahead and consider the possible growth of their operations. Keeping this in mind from the very beginning will make the growth process much easier.
"If a manufacturer is growing, keep in mind the scope of each light fixture when doing so," says Valois. "This can save growers a lot of money if grown in the right amount."
A comprehensive lighting plan takes into account every aspect of the greenhouse and crops, while ensuring an even distribution of light for the healthy growth of plants. Only when all these factors are taken into account can an excellent lighting plan be designed for efficient, effective and thriving growth.