Looking at an orchard in winter you may be forgiven for thinking that nothing is happening. However, there are many important jobs underway and one of those is monitoring the chill hours. The arrival of the recent chill of winter following the warmest December on record is great news for fruit growers, as we need to have a minimum of 820 hours for apples and 620 hours for pears at temperatures below 7.2C, to help the new fruit and leaf buds to develop in the spring.
Technical Director Nigel Stewart explains: “When flower and leaf buds are formed during the summer and autumn, growth inhibitors accumulate preventing the buds from opening during winter. Chilling is then required to break down these growth inhibitors and ensure the buds open at the right time of year. Each tree needs a specific number of chill hours below a certain temperature to break dormancy and that varies from variety to variety.”
Nigel and the team keep a close eye on the weather over the winter months and keep a track of the number of chill hours. If the trees get insufficient chilling, then they may suffer from delayed or uneven flowering and leafing which can lead to poorer crops. As of 2 February, the chill hours which following locations had received are:
So nearly there, and plenty of days of winter left to finish off this stage of the growth cycle!