Ali Sarkhosh, assistant professor of tree fruit and viticulture in the University of Florida’s Horticulture Sciences Department, checks out Florida peach blooms (left) and shows off some fruit. ( Photos courtesy University of Florida Institute of Food & Agricultural Sciences )

The only way peaches can grow in central and southern Florida’s subtropical climate is by using special varieties bred to tolerate low amounts of chill time, but that’s not working as well recently because the low is getting even lower.

These low-chill varieties — such as UF Sun, UF Best and Tropic Beauty — require only 100-150 chill units, said Ali Sarkhosh, assistant professor of tree fruit and viticulture at University of Florida’s Horticulture Sciences Department. 

He’s also a university Institute of Food and Agricultural Sciences researcher who conducts trials on local growers’ land, such as the peach groves in Fort Pierce co-run by Riverside Citrus Harvesting and Titan Farms.

One chill unit equals one hour of temperatures below 45 degrees Fahrenheit between the last week of October and mid-January.

“UF Sun requires only 100 chilling units, the lowest chill variety commercially around the world, but in the last four years, we didn’t have enough chilling units even for this low variety. Weather data showed they had only 50-60 chilling units. 
This is a problem for our growers,” Sarkhosh said.

By teaching new peach growers about thinning the fruit and pruning, Sarkhosh is trying to improve peach size and quality. 

“I’m trying to figure out how we can improve cultural practices, using fertilizers and a plant growth regulator to see if it works in those years when we don’t have enough chilling units,” he said.

Florida weather has always been unpredictable, but it’s getting more so, Sarkhosh said.

But with improved education on cultivation practices and better technology, the future of the industry is promising. 

Sarkhosh estimated that the Florida peach acreage has grown from about 100 acres in 2008 to closer to 2,000 acres today — an estimate that fluctuates as different areas are affected by different weather conditions and other factors.

“If we can overcome challenges of lower chilling units and reducing labor costs like the thinning and pruning, and increasing production, this can be successful industry,” Sarkhosh said.