Peach trees still need more chill hoursBy Stephen Dawkins Published 3:22pm Thursday, January 24, 2013
It’s too early to tell about the taste, but at the very least, this year’s peach crop will be better than last year’s in terms of chill hours.
Chill hours are tallied during the peach trees’ dormant period, when cold weather is valuable because it keeps buds from opening too early, exposing them to a potentially damaging late freeze.
This year’s Chilton County peach crop has experienced between 650–750 chill hours, which are defined as a complete hour where the temperature is at 45 degrees or below, according to Chilton Research and Extenstion Center Director Jim Pitts.
CREC records chill hours at two locations, one at the center itself, in the Collins Chapel community (where 735 chill hours have been recorded), and in the Fairview community (649).
Pitts said there is traditionally a wide variation in the amount of chill hours recorded in the northern and southern halves of the county.
Last year’s crop received only 535 hours, well below the desirable amount.
“We’re feeling better about it, but there are still issues with chill hours yet,” Pitts said. “We still need some more hours.”
Pitts’ concern stems from the fact that, though this winter has been generally colder than last year, there have still been periods of relatively warm temperatures. There have been years when chill hour tallies indicated the crop should be in good shape, but many peaches still ended up misshapen, an indicator that trees weren’t dormant long enough.
According to a “modified” chill hour scale–which instead of beginning the count on Oct. 1, like the traditional method, requires a stretch of cold weather before keeping track–Chilton County peach trees have received 535 chill hours.
Even that number puts this year’s crop on pace to exceed last year’s 650 chill hours. About 1,000 chill hours are ideal, Pitts said.
Feb. 15 is the cutoff date for chill hour accumulation.
When a proper number of chill hours are attained, trees tend to bloom and then bud all at once, allowing growers to be more efficient when harvesting. Such a situation is called a “popcorn bloom” and would occur the first week of March.
“What they like to do is go ahead and just pick an orchard two or three times,” Pitts said.
Trees that don’t experience enough chill hours bloom and bud at different times, possibly beginning in the middle of February, and the fruit grow in a shape that is not ideal.
Another problem mild winters can cause is buds that open before there are enough leaves on the tree to supply them with necessary nutrients during the most critical period of their growth.
Most of the work done in orchards preparing for the growing season–including fertilizing and pruning–will begin Feb. 1.