Following an earlier than usual bud break in March, warmer than normal temperatures have pushed much of California’s raisin grape crop off to a fast start. At the same time, figures compiled by the Raisin Bargaining Association show bunch counts running about 17 percent lower than last year.
Some reduction was expected, given the cyclical nature of grape production from one year to the next. But, some of the drop in bunch numbers is probably the result of lack of rainfall this winter and limited supplies of water for irrigation, notes Steve Spate, grower representative for the RBA.
The state’s raisin production, consisting mostly of Thompson Seedless grapes, is centered within about a 50-mile radius of Fresno. However, raisin vineyards range from Bakersfield area north to Madera.
In mid-April, this year’s crop was tracking about 10 to 14 days ahead of last year’s crop, which was on the early side of normal, Spate reports Development so far points to the bloom beginning as early as the last week of April, he notes. In some years, blooms may not appear until as late as mid-May.
“Growers are a little concerned about starting the season with the potential for fewer grapes on the vine,” says Spate, a grower himself. “Now, it’s a matter of taking care of the grapes that we do have.”
That could prove easier said than done, considering the continuing drought. Many raisin growers are facing reduced deliveries of surface water by their local irrigation districts. Some are on the waiting list for well drillers to extend their wells deeper to tap into dropping water tables. And some, long accustomed to relying entirely on surface water to irrigate their vineyards, suddenly find their pumps, control panels, motors or bowls in need of repair before they can draw on supplies of groundwater for their vines.
“In checking fields in various irrigation districts, I’ve seen some vineyards that either weren’t irrigated last fall or had not yet been irrigated this spring,” Spate says. “There, limited shoot growth is very noticeable.”
He has received an increasing number of reports of erratic delayed growth, where some areas of fields are not growing as vigorously as others. This difference has become more apparent with the warm weather. It may reflect the impact of stress on the vines from last year’s large crop and Lack of winter rainfall and irrigation to fill soil profiles with needed moisture, he notes.
The dry winter allowed many growers to complete their fieldwork earlier than usual. However, Spate received several reports of grower who were delayed in getting their vines pruned due to a shortage of workers.
“Growers remain apprehensive about having an ample supply of labor when they need it,” he says. “But, this year, water availability tops their lists of concerns.
“There’s a fine line between conserving limited supplies of water to irrigate your vineyard and still producing a decent crop. Most growers are trying to hang on this year and irrigate as needed and as they can, while hoping next winter brings the snow pack to the mountains that we need to replenish our water supplies.