Unseasonably cool temperatures this spring have resulted in some beautiful-looking vines in Monte Schutz’ Thompson seedless vineyards near Caruthers, Calif.
But, by mid-June, the cool weather had also slowed development of his 2011 raisin grape crop by about two and a half weeks. That’s a concern for him and other Central Valley raisin growers.
To harvest a crop that will make good quality raisins, their grapes will have to achieve the minimum needed sugar levels, at least 20 degrees Brix, by the end of August, and that will require help from Mother Nature to speed crop growth.
“We have a long way to go,” says Schutz, current president of the Raisin Bargaining Association (RBA). “Daily high temperatures of 95 degrees or more and cool nights for the rest of June, through July and August, would help tremendously.
“We were behind last year, but probably not this much, and the grapes did catch up to make surprisingly decent quality raisins. I don’t think we can make up two and a half weeks, but any time we can make up will help.”
Ideally, growers would simply delay the normal start of harvest by two and a half weeks — but that’s not a viable raisin-making option.
“We have about a four week window to pick grapes — from the end of August, when they normally make sugar, to Sept. 20 when, for crop insurance purposes, grapes have to be on the ground.”
Picking grapes later than that increases the risk of damage from fall rains as berries dry on trays in the field.
There’s also the matter of labor availability. Not every grower can get grapes picked in the ideal period before Sept. 20.
Picking before grapes reach maturity can also hurt a grower’s profits. “
If you don’t take care of your fruit and pick too early, you can end up with a lot of substandard quality raisins,” Schutz says. “You can lose a lot of weight.
Nevertheless, he’s feeling good about his grape crop this year. The vineyards began blooming at the start of the third week of May, and thanks to a few days of hot weather, bloom was finished about a week later. Based on his bunch counts, which are a little higher than last year, he’s expecting an average size crop. That’s assuming favorable weather for the rest of the season.
He continues with his mildew control program, which he began at the end of March when vines had pushed out 2 to 3 inches of new growth. He rotates sulfur treatments between dusting and wettable powder sprays and also applies various fungicides as needed. Lately, he’s been applying sulfur every seven days.
“So far, we’ve had good mildew control with the sulfur,” Schutz says. “I’m keeping a close eye on the vines for mildew and will keep treating once a week until veraison.”
Normally, berries begin soften around July 4, but this year that probably won’t happen until at least mid-July, he says.
Also, he’s ready to clamp down on any mite flare-ups. Usually, they become a concern once temperatures rise above 100 degrees.
“Last year mites weren’t much of a problem,” says Schutz. “But I always have to be aware of them — when the weather gets hot, they can explode quickly. I use fish oil and treat the minute I see them.”
Like other raisin growers, he is upbeat about prospects for another profitable year, reflecting the improved economics of raisin production.
“I’m excited about this year,” he says. “Everything in the market is positive.” The RBA has already secured a field price of $1,500 per ton for this year’s raisins.
Schutz also is vice chairman of the Raisin Administrative Committee, which sets the free tonnage figure. That’s the percentage of the field price that growers receive from packers upon delivery of their crops. It’s based on raisin shipments to date, the projected size of the current crop and the industry as a whole prior to harvest. He expects this year’s free tonnage to be set by early August.