Christine Gemperle doesn’t like bare orchard floors in her almonds.
“I’m a big proponent of having green stuff growing in my orchards,” she says.
While appearance may be a factor, it’s not the only one she cites for wanting cover crops in her orchards.
Gemperle and her brother, Erich, farm 40 acres of almonds near Turlock, Calif. and another 93 in nearby Gustine. They use cover crops early in the season to give arriving bee colonies a jump start from their overwintering status and to help promote soil health throughout the season.
Christine admits the cover crops in the family’s Gustine orchard are currently opportunistic weeds that are mowed and managed the best that weeds can. At their Turlock farm, the cover crop is a mix of mustard and clover provided by Project Apis m., or PAm for short.
Through its “seeds for bees” program, PAm provides seed mixes each year to growers interested in cover crops as a means to promote honeybee health, particularly during California’s almond bloom, which is the largest congregation of honeybees for a single pollination event in the United States.
Billy Synk, director of pollination programs for PAm, manages the “seeds for bees” program. He works with the Gemperles to provide seeds and management advice on cover crops.
According to Christine, the cover crop plays into her strategy of promoting bee health, something she has been keen about for years as a hobbyist beekeeper. She maintains anywhere from 2-12 hives at any one time.
The idea for cover crops came several years ago with her involvement in the Delta Bee Club. During those gatherings she learned from commercial beekeepers the trials and tribulations of beekeeping.
“Then you begin to realize how hard it is for them to keep their bees alive,” she said.
To her, cover crops are much about promoting bee health and forage opportunities at a time of the year when there are no other forage opportunities for bees coming into California for the almond bloom. Bee colonies are typically set in almond orchards beginning in late January while the trees are still dormant and foraging opportunities otherwise tend to be non-existent.
“It really was about providing something for the beekeepers,” she said.
“I work hard to establish good relationships, both personally and professionally, with my beekeepers,” she continued. “I want to be the last person who doesn’t get their bees because of a shortage.”
Once bees arrive on the farm, Gemperle purchases pollen, applying it to the rented hives to give bees a head-start on pollen collection and a jump at brood production and health.
Soil health and synergy
Bee health is one of several benefits cover crops provide in almonds.
According to Synk, the mustard mix does an effective job of out competing weeds and has been shown to suppress soil nematodes. Other benefits of the mustard include preventing soil erosion and helping to increase organic matter in the soil. For every 1 percent of organic matter in the soil its water-holding capacity increases 19,000 gallons per acre, Synk says.
Cover crops also help reduce standing water in orchards, a phenomenon after heavy rains that can delay reentry into an orchard when spray activities must be completed. Synk says he has seen this phenomenon in adjacent orchards, where one orchard has a cover crop and the other did not. In the orchard with a cover crop, water migration into the soil happened much quicker, making it easier for growers to re-enter the orchard with equipment.
Gemperle says she has experienced this in her own orchards.
“This year because we had the bee forage on the ground we were able to get into the orchards after two days,” Gemperle said.
For growers thinking flowering cover crops will compete against almond blossoms for bee time, Gemperle says that has not been the case in her orchards. She says bees tend to work her trees in the morning and by mid-afternoon have moved onto the cover crops.
Over time Gemperle says she learned of other changes that needed to be made on the family farm.
After spending time attending meetings of the Almond Board of California, Gemperle said she learned about a series of best management practices (BMP) promoted by the almond board to enhance bee health.
She now serves on the ABC Board of Directors as an alternate representing Blue Diamond Growers, where she and her brother are members.
Among the BMP’s the Gemperles began practicing a few years ago was the decision to stop using what growers commonly call “tank mixes.” This is a combination of fungicides and insecticides added to a spray rig to reduce the number of passes through an orchard. Beekeepers and university bee specialists believe there is a synergistic effect between the two chemistries that can negatively impact honeybees.
The other BMP they regularly employ is spraying at night, even outside of the bloom period. Christine says they do this to avoid any chance of affecting native pollinators that may be in the orchard.
Yet another practice she uses to promote bee health is the addition of a soaker hose set on a slow drip during those dry periods when bees and other pollinators are foraging for clean, fresh water.
Cover crops 101
Gemperle simplified her planting of cover crops by using a battery-powered seed spreader she purchased at a hardware store. She broadcasts the seed while riding on the back of a four-wheeler while it moves through the orchard.
Almond varieties on the Gemperle ranch include Nonpareil, Carmel and Wood Colony. Once harvest is complete they will go through and prune, immediately chip those clippings for incorporation into the soil, then go through and replant cover crop seeds, which they like to have done before the rains tend to come in November.
The Nov. 1 goal has been easier to meet during the last several years as maturing almonds have allowed for an earlier-than-normal harvest. For some growers, this has meant starting harvest in late July.
Added benefits of planting cover crop seeds in the early fall include warmer soil temperatures for the seeds, and enhancing the likelihood of mustard bloom ahead of the almond bloom. This timing can help the overwintering bees with a nutritional boost and provide a food source for the brood that comes in earlier than the mid-to-late February almond bloom.