Humidity in a polytunnel should be monitored to keep it at an appropriate level. Sometimes, though, it can be a real challenge. Heavy rainfalls can represent a huge obstacle for hobby gardeners as well as plant producers. A constantly damp soil, frequent and abundant rainfall combined with cloudy skies, favor high moisture concentration under cover. This kind of microclimate, lasting too long under cover, can lead to mold growth, pathogens and the appearance of pests.
Humidity in a polytunnel and cultivation under cover
Crops in greenhouses will develop properly when both soil and climate conditions are tailored to the plants’ requirements. Depending on the species and variety, these needs will greatly differ. To be able to control the microclimate, greenhouses are equipped with additional equipment. There are a wide range of accessories available to support growth. The basic one, featuring on multi-vegetation polytunnels, is side ventilation.
Ventilation of polytunnels
Greenhouses with ventilation on both sides are fitted with foil openings. These are raised and shut using a crank. This system provides air circulation inside and enables excess heat and moisture to be removed outside the facility. Thanks to sensors placed inside the structure, growers can check if the microclimate has normalized. An insect net is also included behind the plastic film. Its role is to limit access of pests under the tunnel, where they could feed on crops.
Automatic ventilation systems
Fan devices are another example of such equipment. There are many differences between the various models on offer. More and more hobby tunnels nowadays are fitted with this kind of equipment. Once, these were restricted to commercial farms only. A wide range of products dedicated to small garden tunnels is now at everyone’s disposal on the market. Before deciding to buy, check their effectiveness. Performances are mentioned in the product description. It is important to match the power of accessories to the size of the construction. The bigger the polytunnel, the more devices it will require.
Fan location in the greenhouse
The location of devices depends mainly on the cultivation method. In the case of cultivation at ground level or on tables, fans can be hung at a height of about 120 cm, although this is not a definite rule. If shelves are fitted in the greenhouse for the plants to mature, the equipment should operate slightly above the level of the pots. In greenhouses, hot air as well as condensation, can accumulate within the structure, which is why, for some models, a fan is added in the center of the construction.