What can ruin the harvest time

Frost damage - "Harvest can be ruined in one night": Solothurn fruit growers fear for their cherries due to frost

"Harvest can be ruined in one night": Solothurn fruit growers fear for their cherries due to frost

Last week the temperatures in the canton of Solothurn fell below zero degrees at night, now more frosty nights are announced. Benjamin Meier from Brunnenhof in Metzerlen explains how to arm himself against the cold.

Benjamin Meier opens a cherry blossom and looks inside. At first glance, he can see whether or not it can produce a fruit: if the pistil is green, everything is in order. However, if it has turned black, the flower is broken and the fruit is lost.

On Monday morning, Meier found many black pistils on his cherry plantation in Metzerlen. Like many other farmers in the canton of Solothurn, Meier is also worried about his fruits. This is due to the cold nights that have piled up since last week. And the forecasts for this week are also bad: Several frosty nights are announced, especially the night leading up to tomorrow, Tuesday, causes Meier worries: the thermometer in the Schwarzbubenland could drop to minus four degrees.

Temperature warning by SMS

The frost candles on Meier's cherry plantations were set up last week. However, the farmer makes it clear: "We cannot afford to heat for several nights in a row." The frost candles are used extremely specifically: Meier receives an SMS in the middle of the night if the temperature drops to minus one degree; then Meier gets up and goes to light the candles. With their help, the plants have a degree warmer.

A great cost and time investment - for a single degree. But Benjamin Meier explains: "Every degree is decisive whether the flowers survive or not." There are also big differences on a small scale: not only from village to village, but even from plantation to plantation.

50 percent crop failure for the cherries

It remains to be seen what the coming nights will bring, but there will be serious damage. Meier cannot give a reliable estimate - the year is too young and the influencing factors that determine the crop yield are too complex. But at the current status, Meier estimates this year's harvest failure for the cherries to be 50 percent.

Meier also grows apples, pears and plums on his farm, the Brunnenhof, in addition to his fifteen types of cherries. He is happy that the apples have survived the frost so far because the apple trees are not yet in bloom. Because the real problem with frost damage is not the cold. "The problem is rather that the plants bloom earlier and earlier and are therefore susceptible to frost earlier and longer," explains Meier. Thus, the frost damage mainly affects plants that are already in the vulnerable stage in April.

Apricots and peaches are also at risk

This is also confirmed by Philipp Gut, an expert in fruit and vegetable growing at the Wallierhof Agricultural Education Center. He says trees will bloom two to three weeks earlier now than they did 30 years ago. This makes the situation particularly difficult for stone fruit. "Apricots and peaches are very endangered and have probably suffered major damage," explains Gut. The Schwarzbubenland was particularly hard hit by the frost damage this year because the temperatures have been warmer than in other regions and the flowers are therefore already further developing.

Gut assesses the current situation as critical. Some of the flowers were already frozen last week, and with the cool temperatures that are hot this week, things don't look any better. It is possible that up to 90 percent of the flowers will break - but from 90 to 100 percent it is only a small step. Gut sums up the mood of many fruit growers: “We have been 'burned' several times in recent years. You tend to lose your optimism. "

Frost protection measures: yes or no?

Well knows companies at the southern foot of the Jura that have suffered several total failures in recent years. Gut describes how fine the details are, which determine the loss and gain of the harvest, using the example of overcrown irrigation. This technique is used to protect apples from frost. "Irrigation normally protects against the cold, but when wind comes up at the same time, the water cools the plants instead of warming them," explains Gut. He puts the fruit growers' dilemma in a nutshell: "One wrong decision and the harvest will be ruined in one night."

The question of whether or not to water the fruit growers will have to ask themselves again on Wednesday. Then minus three degrees are the order of the day - just about the critical temperature for apples. Farmers will once again have to make a difficult decision.