The intense cold and severe frosts registered last week in the fields of Huelva have forced raspberry producers to resort to a technique almost as old as humanity to save their productions inside the greenhouses: fire, with the use of so-called anti-frost candles.
These candles are made of paraffin, a product that can provide 12,000 kilocalories per kilogram; enough to quickly raise the temperature inside berry greenhouses at times of particularly low temperatures and minimize the impact of frost, avoiding the freezing of flowers and fruits.
These anti-frost candles are replacing the traditional burning of straw bales; a method that, according to experts, is not the most effective, in addition to causing environmental and public health issues due to the clouds of smoke it generates.
And not only that. Paraffin candles have other advantages. They are biodegradable and are classified as not dangerous and not harmful to people's health. Their combustion takes place without releasing harmful or corrosive vapors. They also have between 10 and 12 hours of autonomy, and their cost is low compared to other systems used for the same purpose.
Low temperatures reducing productivity by up to 30%
Despite the anti-frost candles, the intense cold last week had an impact on the harvesting, especially that of raspberries "which is a much more delicate fruit," says Cristian Cumbreras, berry producer from Palos de la Frontera. According to Cumbreras, low temperatures affect mobility and the sense of touch in the hands, which in his opinion "are essential for the picking of this delicate berry."
To this we must add that the fruit doesn't have the same quality, "since the ideal temperature when harvesting raspberries is around 7 or 8 degrees Celsius. All this, he says, "may cause the productivity to fall by up to 30%."
Lastly, he concludes, the plant also "suffers" as a result of the low temperatures by "becoming lethargic and, therefore, producing much less fruit."