The unseasonably warm weather in the last couple of weeks has many growers concerned about the prospect of an extremely early season. This winter, besides the cold temperatures we experienced in mid-January, it has been an overall mild winter. The warmer winter temperatures have increased the overall chilling accumulation compared to previous years, but it has also resulted in overall less cold hardiness. These two factors, coupled with the warm weather we have experienced in February, will result in earlier bud break than in previous years.

Unfortunately, we currently don’t have the tools to predict exactly when bud break will happen. Some of you have contacted me asking if calculating Growing Degree Days (GDD) could be used for estimating bud break; unfortunately, GDD is not a good predictor of bud break. We have certainly accumulated more growing GDD in the previous 5 years at this point in the year, but there is no GDD threshold that will predict bud break.

In the past 2 weeks, even though we experienced maximum daily temperatures over 60˚ F, these have been accompanied by daily minimum temperatures below 32˚ F, which have probably helped buffer the impact of the warm weather, keeping those buds dormant for longer. Looking at the weather forecast for the next seven days, it looks like, at least for the southern part of the state, this will no longer be the case, and I anticipate these conditions will accelerate the loss of cold hardiness and push us into an early bud break.

A note for the fruit trees growers that are still pruning, this warm weather should not affect at all your dormant pruning. Continue pruning as you would normally do, you can keep pruning past bud break all the way until bloom.

This article was posted in Other News and Resources and tagged Amaya Atucha, gdd, Pruning, resources, warm weather.