The cultivation of soft fruits such as strawberries, raspberries, and blueberries in controlled environments, greenhouses or polytunnels covered with polyethylene films, has become increasingly popular in recent years.
Strawberries are the most popular among soft fruits, due to their bright red color, their unique smell and taste and at certain times of the year consumers are willing to pay increasing prices due to the market shortage.
Protected cultivation, especially for sensitive crops such soft fruit, allows growers to manage environmental factors effectively, ensuring higher yields, better quality and extend growing season to face market availability challenges. Modern polyethylene films used for soft fruit cultivation offer several advantages, including, thermal insulation, high light transmission, light diffusion, anti-dripping properties, chemical resistance and UV open films for enhancing color formation. These features make them essential for optimizing growing conditions, enhancing productivity, and maximizing economic benefits, while also helping to prevent undesirable effects, especially in sensitive crops like soft fruits.
Protection from environmental factors
Soft fruits are very sensitive to unfavorable weather conditions, including wind, hail, frost, and excessive rainfall. Heavy rain can cause waterlogging, hail can damage fruits and frost can ruin flowering as well as early fruiting.
Plastic films protect crops from weather-related risks, especially soft fruits, by reducing fruit splitting and disease from water exposure, minimizes damage to fruits, and ensures that flowers and fruits avoid damage during early or late frosts, i.e. creating a favorable environment for optimal plant growth and production. Special films with superior mechanical properties offer enhanced protection against wind and hail while also allowing for thinner, more cost-effective options.
As extreme weather conditions are becoming more frequent, growing crops under cover provide stability regardless of weather changes. The risk of damage of soft fruits from unpredictable weather events is reduced and the farmers can better plan their production and minimize losses. Moreover, providing a sheltered environment for pickers during harvest makes harvesting more efficient.
Extended growing season
The microclimate created in greenhouses and tunnels, especially by using thermic films, can reach the ideal conditions for plant growth and for longer periods of the year.
Thermic films can offer protection from frost and low temperatures during the cold months of the year allowing earlier planting. Special plastic films with high light transmission and diffusion properties, ensure more uniform distribution of light in the greenhouse or the tunnel so that it prevents burnings and offers a moderate cooling effect.
Excessive heat can have a negative impact on plant growth, development, quality and yield in many regions. Special films with cooling properties can be used to reduce heat load inside the greenhouse or tunnel, prevent crop damage, optimize light transmission and conserve water. A better environment for plant growth during warm months is created and cultivation season is expanded.
Growing soft fruit in tunnels or greenhouses ensures remarkable earliness and can also extend the harvest season, delivering fresh fruits even during traditionally non- productive periods compared to outdoor cultivation in the same area. This results in higher market availability during off-peak times, increasing profitability and competitive advantage.
Enhanced pest and disease control
Soft fruits grown in open filed cultivations are very prone to pests and diseases. Growing inside greenhouses or tunnels protect from birds and insects, while also by controlling temperature and humidity can avoid conditions that can favor fungal diseases. Good hygiene measures and good agricultural practices help to prevent the development and spread of diseases.
Special plastic films with anti-dripping and antifogging properties can help to control the conditions that promote pathogen growth, by avoiding droplets and fog formation inside the greenhouse or tunnel. This can lead to reduced dependency on chemical pesticides, contributing also to cost-efficiency and environmental sustainability.
Increased water use efficiency
Water availability is critical for plant growth and development. The cultivation of soft fruit in greenhouses or tunnels offers substantial improvements in water use efficiency. Water loss due to evaporation is reduced, lowering overall water demand, especially when using mulching films and cover films with cooling properties.
Precision irrigation systems can be also applied, making irrigation more efficient, as well as hydroponic systems that save water and nutrients.
Soft fruit grown under cover can have the optimal water use efficiency and enhanced water management while supporting environmentally conscious agriculture.
Increased productivity and fruit quality
The combined benefits of protected cultivation and pest and disease management can finally lead to higher yields per plant. This is due to the fact that plants are less stressed and can produce more and better-quality fruit, with uniform appearance and taste.
Soft fruit grown under cover are less likely to experience surface blemishes and irregularities due to adverse weather conditions or decrease in flavor caused by excessive water uptake and often achieve higher commercial appeal and premium pricing due to their superior color, texture, and flavor. Plastic films that allow the full spectrum UV radiation to enter the greenhouse or the tunnel can also be used for enhancing color formation in red fruits.
Inside greenhouses it is also possible to apply sophisticated cultivation techniques and achieve extremely high yields. The independence of cultivation in the soil by applying modern hydroponic systems has made it possible to grow crops precisely and achieve extremely high yields. In order to further increase yield per hectare and produce earlier the method of vertical cultivation in the greenhouse has been very popular for strawberries due to the inability of the plants to grow taller and thus to make better use of the greenhouse space, thus increasing production. By using sophisticated plastic films with light dispersion properties, i.e. high-angle light scattering, which is ideal for dense cropping systems and vertical crops, provide enhanced light distribution and protection from scorching.
Conclusion
Growing soft fruits under cover offers significant benefits, such as the off-season production, i.e. at a time when under normal conditions the plants would not be able to produce a product, better crop protection, higher fruit quality, and sustainable water use.
Soft fruits can be grown effectively to both high-tech greenhouses and simple tunnel- type greenhouses. While the initial investment in structures like polytunnels or greenhouses can be significant, the long-term improvements in yield, profitability, and marketability make it a valuable investment.
Whether for small- or large-scale commercial farms, protected cultivation of soft fruit is necessary for meeting the modern challenges in horticulture.