As February ended, walnut grower Dennis Wilt, Biola, Calif., still hadn’t been able to prune his trees.
Following a winter of consistent rains, he was waiting for the ground to dry enough to support pruning towers without rutting up the orchard floor. During the last week of the month, his orchard received half an inch of rain from one storm with half an inch more expected from another storm by week’s end.
Normally, Wilt would have had the work done by now, but the heavy soils have also contributed to the delay. A friend, who grows walnuts two miles away on lighter soils, has finished both pruning and shredding.
“Hopefully, we’ll get done by the middle of March,” he says.
In addition to normal pruning, he also plans to tighten up the ends of limbs broken by last year’s heavy crop. His 20 acres of six-year Chandlers produced almost 6,000 pounds of nuts per acre.
“We had a lot of doubles and triples and they were nice nuts, too, but that load brought down the limbs pretty good.”
A year earlier, the trees yielded 4,000 pounds per acre, Wilt says.
The yields reflect good growing seasons, uniform productive soil, and a few more trees per acre than in orchards where trees are on the more typical 24 x 24-foot spacing. In his case, the trees were planted on former apple ground. By removing every other valve of his flood irrigation system, he was able to keep his existing irrigation valves in place, planting the walnuts 22 feet apart within and between rows.
Last year, Wilt added 24 more acres of walnuts, planting potted seedlings that were grafted in the fall.
Currently, his producing trees are in good, dormant condition. “We had some good chilling hours this winter and we’re just sitting tight right now.”
Wet soils may prevent him from getting fertilizer down before bud break later this month. As with his pruning, normally that work would have been completed by now. His fertilizer program includes an October application of nitrogen, potassium and boron, followed by a late winter feeding. He bands a liquid blend of UN32, potash and boron two inches deep, using a four-shank applicator. That gives him two bands, about two feet apart, on each side of the trees underneath the drip zone.
As with his fertilization, Wilt was also able to make a normal post-harvest application of pre-emergence herbicide on the berms last autumn before the leaves and the rains began to fall.
“I want to make sure things stay clean, because I can’t into the field in winter to spray,” he says. “Otherwise, the weeds would be two feet tall by now. Currently, the fields are clean, but I’ll do a little more herbicide work this spring to touch-up the berms.”