Excessive heat in Valley could impact sweetening process for fruit

US flags fly proudly at the intersection of American and Fruit in Fresno County, where grapes are rapidly developing.

Grower George Matoian and his brother, Richard, put the flags up.

The grapes are getting extra irrigation because excessive heat serves as a red flag.

"If they're not properly hydrated or have got nutrition, then they tend to shut down," George said.

Matoian says that happens when temperatures top 95-100 degrees.

"The vine will go in a shutdown mode, and it will just kind of hold the crop and hopefully, when the weather cools off, then they'll start the photosynthesis again and I'll be able to get going," he said.

Excessive heat means the grapes stop building brix or sugar levels.

"They're pretty close to harvest," George said. "You want to kind of get that nice, frosty green shade to them."

The large bunches of Ivory green seedless were coming on early due to a warmer spring.

"This is one of my favorite varieties," George said. "It's a crunch green seedless grape that is very popular."

They're popular in both domestic and overseas markets.

Matoian says they would've been ready for harvest in another week or two if not for what he calls an unprecedented stretch of excessive heat.

"Warm weather here in the Central Valley is a usual event, but not eight to 10 days of close to 110," he said. "That's a little bit unusual for us, especially this time of year. Usually late July or August is when we experience a pretty good run."

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