- Author: Dustin W Blakey
Vegetable gardening is both an art and a science, and an important technique for success is crop rotation.
By rotating crops, you can improve soil health, reduce pests, and increase yields. Continuous planting of the same kind of plant in the same place every year is a recipe for creating problems.
Here are 8 rules to follow for effective vegetable garden rotations.
Rule 1: Have Light Feeders Follow Heavy Feeders
Heavy feeders, such as tomatoes and corn, consume large amounts of nutrients from the soil. Following them with light feeders, like carrots or lettuce takes advatage of this difference.
Rule 2: Include Some Soil Improvement Crops
Soil improvement crops, such as legumes, enrich the soil by fixing nitrogen. Planting crops like peas and beans can naturally enhance soil fertility, reducing the need for chemical fertilizers.
Rule 3: Rotate Plants with the Change of Seasons
Different plants thrive in different seasons. Rotating crops with the seasons ensures that your garden is always productive and that soil nutrients are used efficiently throughout the year.
Rule 4: Rotate by Plant Families
Plants within the same family often share pests and diseases. Rotating by plant families (e.g., moving from nightshades to brassicas) can break pest and disease cycles, promoting healthier plants.
Rule 5: Use Rotation to Reduce Pest Populations
Pests can quickly become a problem if the same crop is grown in the same spot year after year. Rotating crops disrupts pest life cycles, reducing their populations and minimizing damage to your garden.
Rule 6: Rotate to Deprive Weeds of Light and Space
Different crops have varying growth habits and can outcompete weeds differently. By rotating crops, you can deprive weeds of the consistent conditions they need to thrive, thereby reducing weed pressure.
Rule 7: Winter is a Good Time to Use Cover Crops
Cover crops planted in the winter protect soil from erosion and add organic matter when they are turned into the soil. They also help to suppress winter weeds and can fix nitrogen, preparing your garden for spring planting.
Rule 8: Don't Be Afraid to Change Your Rotation Plan
Flexibility is crucial in gardening. If something isn't working, don't hesitate to adjust your rotation plan. Pay attention to your garden's needs and be willing to experiment to find the best solutions for your specific conditions.
For more information
There are many resources online that cover garden rotations. There aren't too many bad ones, in fact. Perhaps my favorite is a book called Crop Rotation on Organic Farms: A Planning Manual by Mohler & Johnson. You can buy the print version, but it's also available as a free PDF file. It's nerdy and information dense. Probably overkill for the casual gardener, but if you get serious about gardening or Organic production, it's excellent.
For a simpler introduction, see this article from the Royal Horticultural Society.
/h3>/h3>/h3>/h3>/h3>/h3>/h3>/h3>/h3>- Prepared by: Terry Lewis
- Avoid cutting lawns too severely because the resulting stress causes yellowing.
- Water citrus being careful not to over water. Continuously wet soil in the upper few inches risks root rot.
- Hand pick hoplia beetles from white and yellow rose blossoms.
Pruning
- Remove spent blooms. Cut back annuals that have stopped blooming to encourage rebloom.
- De-candle black pines to encourage compact growth.
Fertilizing
- Avoid fertilizing herbs as too much fertilizer reduces flavor and fragrance.
- Last fertilization of citrus this month for this year.
Planting
- Spring planting season is over. Anything planted this month will need careful watering.
- Bulbs, corms, tubers: fall flowering (Crocus).
- Fruits and vegetables: corn, cucumber, plant from seed at timed intervals to prolong harvest.
- Annuals: globe amaranth (Gomphrena), lobelia.
Enjoy now
- Annuals and perennials: fibrous begonia (Begonia semperflorens), clustered bellflower, cockscomb (Celosia), morning glory (Convolvulus tricolor).
- Bulbs, corms, tubers: gladiolus.
- Trees, shrubs, vines: bird of paradise (Caesalpinia), bottlebrush (Callistemon), fringe tree (Chionanthus).
- Fruits and vegetables: apriums, cherry, cucumber, eggplant.
Things to ponder
- Garden and harvest crops in the cooler morning or evening hours.
- Never use honey, artificial sweeteners, or red food coloring in hummingbird nectar.
- Author: Angela Tipsey
Message from the State 4-H Office:
State Field Day 2024 is moving from our usual home to the School of Veterinary Medicine. There are student protest demonstrations taking place on the Quad next to Wellman Hall (our usual home), and counterprotests have begun. We made the decision to move our event to a different part of campus to reduce the risk of exposing our members to any type of conflict that doesn't need to impede their day of learning and fun!
We are lucky to be able to move State Field Day to Gladys Valley Hall, the heart of the educational program of the UC Davis School of Veterinary Medicine!
If you have further questions, please contact the contest coordinator or email us at 4HSFD@ucanr.edu.
For more information about State Field Day go to https://na.eventscloud.com/website/55508/home/
/span>- Author: Saoimanu Sope
UCCE specialist's research prevents water pollution, reduces water use
When interviewed to become a University of California Cooperative Extension specialist in environmental horticulture, Lorence “Loren” Oki was asked what kind of research he wanted to conduct.
In response, he showed the hiring committee a photo of a residential gutter. “Water is a big concern, and I found very little research on runoff from homes,” said Oki, explaining that studying residential runoff is what “started his career” with UC Agriculture and Natural Resources back in 2002.
Although he remains active supporting growers and advising industry leaders, Oki retired from UC ANR in July 2023. Before joining ANR, Oki worked as a researcher for UC Davis' Department of Environmental Horticulture studying greenhouse irrigation in 1994, bringing his total time with the University of California to 29 years.
Oki, professor emeritus of Cooperative Extension at UC Davis, led many research projects that advanced the green industry which includes landscapes, nurseries and floriculture.
“Loren is the epitome of a specialist,” said Darren Haver, UC ANR's Research and Extension Center system director, who has worked with Oki for more than 20 years on projects that have significantly improved urban water quality and water conservation efforts across California.
Research influences pesticide management
With a $3 million grant funding a statewide study, Oki and Haver set out to characterize runoff from residential sources over a five-year period. They determined the volume of irrigation runoff from residential land use, as well as the pollutants in the runoff.
Oki and Haver, co-principal investigators, along with researchers from UC Davis and UC Riverside, discovered that the degradation products of the insecticide fipronil – commonly found in runoff water – were more toxic than its parent compound. The study led to an investigation of human pathogens and pathogen indicators in residential runoff, the first of its kind.
Another contribution was the early detection of a new pesticide used for ant control, enabling strategies to be put in place to prevent it from reaching local streams and creeks. Oki and Haver's work also persuaded the California Department of Pesticide Regulation to change pesticide labels to minimize the chances of pesticides moving off target during irrigation and rain events.
These changes included preventing pesticide application before predicted rain and preventing irrigation after applications, keeping pesticides from impervious surfaces, and restricting applications on lawns and landscape beds within two feet of impervious surfaces and others.
Plant trials expand beyond California
Oki was also the principal investigator of the Climate-Ready Landscape Plants project, which may be the largest irrigation trial in the western U.S., and the UC Plant Landscape Irrigation Trials, the California component of that project. The UCPLIT trials originated in 2004 at UC Davis as a research project by Karrie Reid, retired UCCE environmental horticulture advisor for San Joaquin County, while she was pursuing her master's degree. In 2017, the irrigation trials were duplicated at the South Coast Research and Extension Center.
These projects evaluate landscape plants under varying irrigation levels to determine their optimal performance in regions requiring supplemental summer water. Throughout the trial, Oki identified many landscape plants, including rose cultivars, that remain aesthetically pleasing with little water.
Today, the trials have expanded beyond California as the Climate-Ready Landscape Plants Project at Oregon State University, University of Washington, University of Arizona and Utah State University.
Growing up in the nursery industry
In 2017, Oki obtained tenure, allowing him to expand his professional responsibilities to include production horticulture, specifically greenhouses and nurseries, an industry he was extremely familiar with. “I come from a nursery family,” Oki explained. “My grandfather started Oki Nursery in the early 1900s.”
During World War II, Oki's family was incarcerated in the Poston Relocation Center in Arizona and lost their homes and property. When they were released, they returned to the nursery industry to rebuild their lives. “After World War II, my father and uncle got more involved with my grandfather's work,” he said.
The Oki family played an instrumental role in technological development for nurseries in general. Oki Nursery, which was located in Sacramento, worked closely with IBM and was the first to use a computerized system in the industry.
Oki's father developed computerized scheduling for the bedding plants, poinsettias, chrysanthemums, bulbs and other crops. He developed a method to calculate the cost of any crop grown by the nursery at any point in the crop cycle and computerized greenhouse environmental and irrigation controls. This may not sound impressive now, but that was in the 1980s.
“My father was known for being progressive and he also knew everyone at UC Davis,” said Oki. “He wanted to work with anyone who had an interest in doing something good for nurseries.”
Inducted into Green Industry Hall of Fame
In the 1950s, Oki Nursery partnered with researchers from UC Davis' agricultural engineering program and developed the overhead sprinklers commonly used in nurseries today. Until the 1980s, Oki Nursery was the largest nursery in Northern California. Before it shut down in 1993, Oki worked in the family business as a greenhouse manager when runoff became a growing concern.
“I remember getting served with a notice by the Regional Water Quality Control Board stating that we needed to prevent runoff because it was polluted with nitrate fertilizer, which was common in the nursery industry,” Oki said.
One of those efforts focused on using controlled-release fertilizer instead of applying fertilizer via irrigation as a liquid feed. “What we learned is that if we converted nurseries to controlled-release fertilizer, we could reduce the nitrate runoff,” he said.
In 2023, Oki was inducted into the Green Industry Hall of Fame, which recognizes individuals with a minimum of 20 years in the landscape, nursery or floriculture industry and who have made significant contributions to the field.
Having grown up in the industry, Oki said that his father taught him to never be afraid to try new things. “If you think you have an idea that might work, do the best you can to make it work. If it doesn't work out, then it doesn't work out. And that's OK,” he said.
Revitalizing space for greater impact
This mentality encouraged Oki whenever tackling new tasks, like rebranding the California Ornamental Research Federation, a space for education and collaboration, as UC Nursery and Floriculture Alliance.
In 2009, Oki and David Fujino, executive director of the California Center for Urban Horticulture, became co-directors of CORF, which catered to the cut flower industry. At that time, Oki and Fujino realized that nurseries generated much greater revenue in the state than cut flowers.
“It was a strategic decision to change CORF to UCNFA, which included floriculture and nurseries in the name,” Fujino said. Combined, nurseries and floriculture have consistently placed in the top five agricultural commodities in the state.
When reflecting on their partnership, Fujino said that working with Oki was a “natural fit.” “I couldn't have asked for a better partner, a better colleague and, ultimately, a better friend to have my back and work side by side,” he added.
Since UCNFA's launch, the two have worked to maintain the group's impact by hosting “Ask your Advisor” webinars to connect advisors to growers, as well as co-hosting large-scale events such as the annual conference for the International Plant Propagators' Society — an organization focused on greenhouse and nursery production education — for the Western Region, which Oki's father helped establish in the 1960s.
Encouraging a return to education
Gerry Spinelli, UC Cooperative Extension production horticulture advisor for San Diego County and member of UCNFA's administrative committee, described those who have learned from Oki as his sons and daughters. “When I meet someone that's learned from Loren or worked with him, that person instantly becomes my friend. That's the kind of effect Loren has on us,” Spinelli said.
Grant Johnson, UC Cooperative Extension urban agricultural technology advisor for Los Angeles and Orange counties, credits Oki for his master's degree in horticulture from UC Davis.
“Loren gave me a lot of direction as far as career choices and research interests. He instilled in me a dedication to life-long learning, just like he continues to do,” said Johnson. Before Oki became his professor, Johnson worked with Oki as a staff research associate at the South Coast Research and Extension Center in Irvine.
Another influential person in Oki's life is John Kabashima, emeritus environmental horticulture advisor for UCCE Orange and Los Angeles counties and fellow Green Hall of Fame inductee. Like Oki, Kabashima grew up in the nursery industry.
Oki, who earned a bachelor's degree in ornamental horticulture from Cal Poly San Luis Obispo and a master's degree in plant science from UC Riverside, decided to pursue a Ph.D. in ecology at UC Davis with Kabashima's encouragement.
While Oki was still working in his family's business, Kabashima said that Oki relied on UC ANR researchers for scientific information and felt like Oki wanted to be one of them. “I told him that he's a good nursery guy, but he's a better scientist,” said Kabashima. “His heart is in science.”
The two began working together as soon as Oki became a graduate student and have been colleagues and friends for nearly 40 years. “My favorite response from Loren whenever people ask him a question is, ‘It depends,'” Kabashima said. “It always leads to people opening up and giving more context. That's what Loren does, he gets you to think.”
/h3>- Author: Kathy Keatley Garvey
Those are some of the activities planned when the Bohart Museum of Entomology hosts an open house on managed bees and wild bees on Sunday, May 19.
The open house, free and family friendly, takes place from 1 to 4 p.m. in Room 1124 of the Academic Surge Building, 455 Crocker Lane, UC Davis campus.
It's perfect timing for "World Bee Day," observed annually on May 20.
At the Sunday open house, UC Davis graduate student Richard Martinez of the lab of apiculturist Elina Lastro Niño, associate professor of Cooperative Extension, UC Davis Department of Entomology and Nematology, will staff the honey bee booth.
Martinez, enrolled in the master's graduate studies entomology program, says that the E.L, Niño Lab booth will display an observation hive and offer honey tasting from a variety of floral sources. He will be sharing recent projects aimed at improving honey bee health via dietary supplements. He also plans to showcase beekeeping suits and hive tools.
Among others scheduled to participate (as of 4 p.m. today) are:
- the laboratory of community ecologist Rachel Vannette, associate professor and chair of the UC Davis Department of Entomology. She will participate with lab members doctoral candidate Lexie Martin, doctoral student Dino Sbardellati, and junior specialist Leta Landucci. "At the Vannette Lab booth, you will be able to look into the life of a bee--both in terms of where they live and how they develop!" said Martin. "A live bumble bee nest and solitary bee nests will be available, so you can peer inside a bee's house! Additionally, there will be live bee larvae to observe under a microscope and interactive displays on the bee life cycle."
- Bohart Museum bee scientists Thomas Zavortink and Sandy Shanks
- Doctoral student Sofía Meléndez Cartagena of the Stacey Combes lab, Department of Neurobiology, Physiology and Behavior. She will focus on local bee diversity.
- Chancellor's Fellow Santiago Ramirez, associate professor, Department of Evolution and Ecology, who studies orchid bees
- Doctoral student Peter Coggan of the Ramirez lab. He studies the neurological and genetic basis of orchid bee courtship behavior and evolution.
- UC Davis distinguished professor emerita Lynn Kimsey, who retired as director of the Bohart Museum on Feb. 1, after 34 years as director. Kimsey, known as "the wasp woman," is a past president of the International Society of Hymenopterists. She studied orchid bees in Panama for her dissertation.
The Bohart Museum houses a global collection of eight million insects, plus a live petting zoo, and a gift shop. Professor Jason Bond directs the museum as of Feb. 1, succeeding Kimsey, who served 34 years. Bond is the Evert and Marion Schlinger Endowed Chair of the Department of Entomology and Nematology, and the associate dean, UC Davis College of Agricultural and Environmental Sciences. He also serves as president-elect of the American Arachnological Society.
For more information, access the website at https://bohart.ucdavis.edu or contact bmuseum@ucdavis.edu.
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