When the cold weather arrives in our province and we start to see Sierra Nevada dressed in white, it means that the winter season has begun. A season whose low temperatures make it impossible to produce fruit and vegetables in certain countries around the world, but not in Almeria.

Here, although agricultural production also slows down slightly, the structures of the greenhouses and the care taken by our farmers allow us to continue supplying certified vegetables throughout the winter with the highest quality standards, thus positioning Almeria as the leading European region in fruit and vegetable production and marketing during this time of the year.

Do you know the impact of cold on greenhouses and crops under plastic?

How cold influences crop development

When temperatures are lower than the recommended optimum, one of the most common effects is a decrease in crop development and growth, and thus in production.

But when the cold is very intense and temperatures drop to critical levels, the risk of suffering more serious damage increases. Damage such as loss of flowers or loss of newly set fruit, or even complete freezing of plant tissue if the cold is extreme.

In addition, when talking about the effects of winter on greenhouses, it is also important to highlight frost, as the formation of extracellular ice in the plant tissue tends to cause water to escape until it dehydrates the plant cells and ends up damaging the crops.

Tips

As a fruit and vegetable company, we believe that the best way to prevent and reduce the impact of winter in greenhouses is to rely on the professional advice of our agricultural technicians. Here are some of their recommendations:

• Close the greenhouses after midday and before sunset to maintain the maximum possible temperature during the night.

• Reopen the windows of the greenhouses early in the morning in order to balance the inside temperature with the outside temperature and thus avoid the well-known thermal inversion.

• Water in the middle of the day to promote a good humidity level in the greenhouse.

• Depending on the crops grown or the type of greenhouse, the use of thermal blankets or the installation of double roofs, among other recommendations, may also be necessary.

Impact of cold on auxiliary insects (biological control)

Did you know that temperature affects the auxiliary fauna in our greenhouses in Almeria? In fact, it is the abiotic factor that most influences their behaviour and population levels.

On the one hand, it reduces the reproduction and fecundity capacity of the auxiliary fauna, which, by laying fewer eggs, reduces its survival capacity and, therefore, its establishment in the crops and its population level.

On the other hand, not having as many hours of daylight as in other seasons of the year will have a negative impact on the photoperiod and its activity.

Tips

In order that the biological pest control allies do not disappear or cease their activity, it is essential that, both inside the greenhouse and in the crops themselves, there is a microclimate that favours the survival of our auxiliary insects.

The use of double roofs in greenhouses will help growers to increase the optimum temperature to maintain the activity of the auxiliary fauna.

Likewise, it is also possible to improve their establishment in the crops by reinforcing previously introduced populations when conditions permit; or to opt for supplementary feeding (prey) for the auxiliary insects to counteract the shortage of food in winter and thus favour the development and survival capacity of our auxiliary fauna.