Candles protected our orchard from late frosts

On the night of April 30, ground frost hit our country, which poses a risk to fruit trees during their flowering period. “The frosts caused damage to fruit growers amounting to hundreds of millions of Czech crowns,” said the chairman of the Czech Fruit Growers’ Union, Martin Ludvík. At our station in Střížovice, we therefore had to prepare in advance to protect our most valuable varieties and new selections.

Our colleagues Jan Zima and Zdeněk Haleš lit 50 anti-frost candles in the orchard at night. They placed them mainly near selected elite new breeding selections and mother trees, on which we are currently carrying out controlled pollination in order to develop new varieties with excellent characteristics. Protecting these genotypes is therefore essential for the future and continuity of our breeding program.

According to data from the weather station in nearby Pěnčín, the ground temperature dropped to as low as −5.5 °C, while the air temperature reached approximately −3 °C. The heat source provided by the candles may have helped reduce the risk of damage to the blossoms, which are currently in their most sensitive stage of development. Unfortunately, the effects of the frost were further intensified by the ongoing drought. A more precise assessment of any damage will only be possible in a few weeks.

At our station, we also have anti-frost machines available to protect flowering trees from spring frosts, but we did not use them this time. The forecast did not indicate a stronger or longer-lasting frost, and their use would also have been limited by strong winds. Their operation is also economically demanding.

Our nighttime intervention was accompanied by the sight of dozens of flames scattered throughout the orchard, helping to protect not only this year’s harvest but, above all, the future of our long-term breeding work.