As March was winding down, the walnut trees in Jack Gilbert’s orchards near Wheatland, Calif., were still dormant.
But, his Serrs were just starting to push out catkins. As usual, they were the first of the Yuba County grower’s varieties to do so this season. They should be followed by Ashleys and Chicos before clusters of pollen-bearing male flowers begin forming on the rest of the varieties. They include Chandler, Hartley, Tehama and Vina, as well as a few 80-year-old Franquettes that his father planted.
This activity comes after a rainy, late fall and early winter, followed by dry weather from late January through February before rains began again in early March.
“We’ve had about six inches of rain since then and are ahead of normal for the year,” Gilbert says. “We’ve had this kind of weather before, so I’m not really worried at this point. The trees should be OK.
“Our blight sprays should take care of any fungal diseases. We’ve had quite a bit of good chilling this past winter, and we’ve had no damage to trees, despite some pretty strong winds, except for losing an occasional older tree suffering from root rot.”
This year’s fertilizer program began the first week of April. He’ll treat most of the trees with liquid UN32, applied at the rate of 100 pounds of nitrogen per acre through the solid set sprinkler systems used on all his orchards.
In orchards with tight soils that impede water penetration, Gilbert will apply the same rate of nitrogen in a broadcast application of more expensive calcium nitrate.
Come summer he’ll repeat the treatment. Depending on how the trees are doing, he’ll put on nitrogen in one application in August or split the treatment, applying half in early July and the rest in August.
Normally, there’s no need to give the trees any other nutrients.
This will be the fourth year that Gilbert will use pheromone-emitting puffers to help control codling moth by disrupting mating. He places one puffer for every two acres, hanging them a little closer together on the orchard borders to insure adequate coverage of trees on the edges. Last year, he installed puffers on 350 acres where varieties, particularly Chandler, are susceptible to the insect.
“For the first time, we didn’t apply any insecticide to control codling moths, and damage in those areas from the insect was less than 1 percent,” Gilbert says. “The puffers don’t save any money compared to insecticides, but they are much better for the environment.”
Gilbert has farmed full time for the past 35 years. He and his wife, Sandra, bought their first walnut orchard in 1970, the year after they married. Today, their Rio Oso Groves total 275 acres of walnut trees. The Gilberts and their two sons, Jack, Jr., who farms with them, and Henry, an anthropology professor at Cal State East Bay, and other family members also own Gilbert Orchards, a separate 460-acre walnut operation, which Gilbert manages.
Because of last year’s record walnut production, including a record Chandler crop, Gilbert expects yields in California orchards to be down somewhat this year. Still, he’s upbeat about his crop and the industry as this new season gets under way. In fact, his plans call for adding more walnut orchards next year.
“Last year, California’s walnut crop was significantly larger than the year before and they sold well,” he says. “Consumers like the health benefits from eating walnuts and the international demand is growing as the standard of living and ability to buy higher quality foods increases. It’s a great opportunity for those of us in the industry.
“I’ll continue growing walnuts for as long as I can,” Gilbert says. “It’s a really good life and I enjoy the orchards. They’re very pretty. I like living around them, and the work, especially the harvest, is very enjoyable.”