Cold temperatures failed to materialize as forecast in the Central Valley citrus belt. Growers report that overnight lows dropped to the low 30s and stayed well within the “sweet spot” for the area’s citrus crop, according to a California Citrus Mutual spokesman. The warmer temperatures are attributed to decent cloud cover, particularly in the Foothill areas, a consistent breeze, and generally moist conditions.
Growers report running wind machines in the early morning hours as a precaution against ice mark, which can compromise the external quality of the fruit and cause undesirable blemishes on the rind. The potential for ice mark occurs when the fruit is wet due to rain or moisture in the air and temperatures fall to below freezing, particularly 2-3 hours before sunrise. Although temperatures were relatively high, wind machines were utilized to dry the fruit and effectively prevent ice mark damage.
On average, wind machines ran 4-6 hours beginning at 4:00 a.m. on Thursday morning, primarily to eliminate the potential for ice mark. For the less cold tolerant mandarins, wind machines were effective at keeping temperatures above critical lows which is generally 32 degrees. In contrast, the navel orange crop can tolerate temperatures as low as 27 degrees.
The Central Valley orange crop is approximately 25% harvested to-date and the mandarin crop is at 30% harvested. With 70-75% of the crop remaining on the tree, growers will continue to keep a close eye on weather conditions until at least the end of January. Historically, the area’s most severe freezes have occurred the week of Christmas. One exception in the recent past was the 2007 freeze which hit in late January.
All in all, it was a good night for Valley citrus growers. The forecast currently shows temperatures will drop into the 20s Thursday night into Friday morning and possibly Friday night into Saturday morning. Growers are optimistic that the moisture in the air at present will help keep the ground moist through the day and aid in frost protection efforts tonight should cold temperatures materialize.