(May 8, 6:17 p.m.) The highest incidence of seeders in years should keep celery markets strong at least into late May, grower-shippers predict.

Some seeders are normal for this time of year, said Ross Widerburg, sales manager for Boskovich Farms Inc., Oxnard, Calif. Seeders occur when the middle of the plant grows faster than the outside, causing fewer stalks to grow per plant.

But this year, it’s probably as bad as it’s been in four or five years, he said. As a result, yields are down about 30-40%, he said.

And with Florida out of the deal by the first week of May, it’s having an effect on markets, he said.

“The market’s starting to show it now,” he said May 7. “It could go up to $20. And I don’t see any change in volumes through the end of May.”

On May 6, the U.S. Department of Agriculture reported prices of $16.65-17.60 for cartons two dozen from the Oxnard growing region of California, up from $14-16.50 last year at the same time.

The first week in May, Coastline Produce, Salinas, was winding up its Oxnard celery deal, where seeders had been found, and starting in Santa Maria, where quality looked good, said Mark McBride, sales office manager.

The combination of seeders and light volumes the first half of May out of Santa Maria should keep markets “very high” at least through May 20, McBride predicted.

Cool weather also was holding plants back as of May 7, with more unseasonable weather forecast through May 12, he said. Highs in the mid- to high-60s aren’t that much cooler than normal, McBride said, but celery plants are sensitive to any drops.

“A few degrees can make a big difference,” he said.

Weather extremes have contributed to the high incidence of seeders, with growing areas enduring both frost and 90 degree temperatures in recent weeks, Widerburg said.

Boskovich expects to begin shipping celery from Santa Maria in June, Widerburg said.