In previous articles, we have talked about the benefits and importance of using plastic films in agriculture as a way to boost farming, extend growing seasons and increase production levels. This time, we will discuss the color of plastic covers for greenhouses and how to know if the choice of the same will influence the development of the crop.
While one of the benefits of using plastic films in greenhouses is the fact that you can use solar and thermal energy more efficiently, the key is to know how to determine, based on the type of crop and climate of each region, the color of the plastic cover for the greenhouse that should be used to take full advantage of it while caring for the plants.
Why is transparent plastic so popular?
One of the most popular beliefs among many agricultural producers is that the more sunlight that covers the crop, the better, and that’s why you usually see crops in greenhouses where only very transparent, or glass type, plastics are used.
While it is true that sunlight is crucial for the crop to thrive, the truth is that when it comes to crops in greenhouses this will mean that an increase in temperature will take place in much lesser time, resulting in the risk of burns to the plants and fruits.
To avoid catastrophic scenarios, it is vital to understand what conditions do plants need and how the color of plastic films influences crop performance.
What is the difference between direct light and diffused light?
In addition to the color of plastics, the other concepts that must be understood and applied when it comes to crops are sunlight and the types of natural light that exist, which are direct light and diffused light.
Direct light refers to direct sunlight and diffuse light refers to scattered waves of light. In this case, agricultural plastics are placed over crops to transform that direct light into diffuse light, and this is achieved when the rays pass through a translucent material.
Diffused light can also be produced naturally thanks to the dispersion generated by the atmosphere or the clouds. However, when it comes to covered crops, it’s best to make sure that everything is under control using plastic films.
What should be the color of plastic covers for greenhouses?
It’s all going to depend on how the greenhouse is used. For example, if the greenhouse is used to germinate seeds or young plants that will later be moved outside, the recommendation is to use a colorless plastic film that allows the entry of more direct sunlight to increase the temperature and boost the germination process.
Using colorless plastic films in greenhouses has many advantages, such as emitting direct light to the structure to heat the soil, while providing an adequate temperature for seeds to sprout. When this happens, seedlings usually grow fast and strong and can be moved to an outdoor area without inconveniences.
However, a disadvantage of using colorless plastic films in greenhouses, compared to more opaque films, is the fact that the light that enters directly creates hot spots, while there are other areas in the greenhouse crop with a lower or colder temperature where plants remain in the shade. Additionally, an environment with excess heat can be generated, which is trapped inside the greenhouse structure compromising the integrity of the crop.
This risk of increased heat in certain areas or duration of excessive solar radiation is minimized with the use of plastic covers with a certain percentage of opacity, usually manufactured with polyethene or fiberglass, since they help dissipate more evenly the waves of sunlight that reach all areas of the greenhouse, reducing the development of fungal spores, as well as the spread of insects and making photosynthesis more efficient, which results in optimal growth.
These more diffuse plastic covers are ideal when you have vertical crops and high vegetable crops. However, a negative aspect of them is that we must make sure that light problems in the crop won’t arise during the year since, in general, opaque plastics subtract light overall.
Depending on the region where the crops are located through greenhouses, one of the aspects that concern agricultural producers the most is being able to control the high temperatures that occur within the structure, as they can compromise the integrity of the crops and decrease their productivity.
For more information about some studies that have been developed to determine the incidence of the color of plastic films in covers for greenhouses, we recommend you click on this link here.
If the plastic film is photoselective, does that affect the color of the plastic cover for our greenhouse?
Juan Antonio García, Greenhouse Plastics Product Manager of the Armando Alvarez Group, in Spain, points out that when it comes to a photoselective plastic the color can directly affect the processes of the plants and therefore, the fruits and their production, sprouting, follicular development, flowering, fruit color, disease reduction, etc.
On the other hand, when the material isn’t photoselective, “it will mainly affect the overall transmission of light or the amount of light that will enter the greenhouse. Of course, this non-photoselective cover will also definitely influence numerous processes of the plant, but not due to its color, but based on the type of product formulation (diffusion, specialty additives,… etc.).”
For more information on this topic, we recommend reading our article on the importance of the photoselective properties of plastic films used in greenhouses.
The importance of plastic films in crops
The use of plastic covers in agriculture will continue to grow and gain popularity thanks to the multiple benefits they have for agricultural producers.
Nowadays, more companies are dedicated to the manufacture of plastics designed specifically to meet the current requirements of farmers, and as a result, these companies are constantly investing in state-of-the-art technology to develop such covers.
Hence the importance of monitoring and modernizing the processes involved to achieve a high level of quality in agricultural plastics, since that will result in films that allow improving crops, save production costs (reducing the investment in pesticides, water consumption, and heating, among others) and protect the areas intended for cultivation.
If you have any questions or concerns about how to choose the right plastic film for your crops, don’t hesitate to contact us.