Seeding for both radicchio and cabbage took place on June 22nd. Seeds were initially sown into ¾” plug trays. It is important to note that in radicchio, optimum germination results at soil temperatures of 60-68°F, so it is vital to keep soil temperatures cool. Therefore, the trays were placed near the door of the heated greenhouse to allow for more ventilation.
FIELD PREPARATION
On June 24th, Andrew and I began setting up the experiment by spading and squaring-off the assigned field at the Evergreen Organic Farm. We pulled mountains of bindweed, buttercup, and thistle. We measured out beds and paths for half of the field and harrowed the beds in preparation for planting buckwheat. In the afternoon, Dr. Sarah Williams joined us as we used an Earthway seeder to sow six varieties of buckwheat provided by the University of Washington: ‘Koto’, ‘Kitawase’, ‘Koma’, ‘Horizon’, ‘Mancan’, and ‘WSU Pop’.
Andrew Luttinen standing with a bag of buckwheat and a grin. Image by Sarah Dyer.Andrew Luttinen uses the Earthway Seeder to put in five rows of buckwheat per bed. Image by Sarah Dyer.Dr. Sarah Williams and Andrew Luttinen water in the buckwheat . Image by Sarah Dyer.
The remainder of the week was spent monitoring the field and greenhouse for germination, pulling the ever-encroaching bind weed, and planning for an evaluation of germination for all varieties planted.
Although most SURF fellowships are generally conducted during the ten week period of summer quarter, the nature of agriculture necessitates planning in spring and harvesting in the fall. With this in mind, I began my work choosing which vegetables and varieties I would grow and designing a replicated block variety trial.
WHAT IS A REPLICATED PLANT VARIETY TRIAL?
The primary objective of a variety trial field experiment is to test the performance of crop varieties relative to each other. To do this, trials are designed to eliminate as much variability as possible to strengthen the ability to detect a difference in variety performance. As with any field trial, there will always be variability in the field that is difficult to control. Weather, soil type, and pest pressure are just a few of the factors that introduce variability into field research.
A replicated variety trial has two main parts, “plots” and “blocks.” The purpose of replication is to account for differences due to environmental variation in the field. Typically, this requires dividing the field into “blocks.” This is called a randomized complete block design and it is the most common design for replicated variety trials. Each variety is planted in a “plot” and the complete set of varieties you are testing are arranged into “blocks” that are replicated a certain number of times, usually 3-5 times. Each variety is present once in each block.
Every plot in the trial is treated identically in respect to planting date, planting depth, harvest date, data collection, pest management, fertility, etc. Variety is the only variable we allow to be different. “Plots” are delineated by stakes or flags, each marked with a code assigned to a particular variety.
WHY CONDUCT A VARIETY TRIAL?
Organic producers have fewer allowable inputs for mitigating crop stresses than their conventional counterparts and instead rely on agroecological practices, and a growing body of research suggests that the varieties that perform best on organic farms may not be the same as on conventional farms, and that organic farmers may benefit from using varieties bred specifically for organic systems. Variety trials are particularly useful for farmers transitioning to organic production, seeking varieties bred for low-input operations, or looking to replace conventional varieties or seed sources.
Identifying unusual or exceptional varieties, varieties with a story, superior flavor, unique colors, and varieties available early or late in the season can help fill a vital market niche for some growers. Conducting an on-farm variety trial prior to expanding production of new, unknown varieties prevents the difficult lesson of losing a crop. Testing new varieties in trials throughout the season can ensure they are adapted to the growers’ specific conditions and seasonal needs.
As weather patterns become more extreme and unpredictable, it is crucial to evaluate what varieties do best when the climate is in flux. Testing out which varieties perform best in stress from drought, flooding, and cold snaps could help cropping systems be more resilient in future years.
Additionally, participation in field trials will enhance The Evergreen State College’s Food and Agriculture Pathway of Study curriculum by creating connections with participating institutions, produce for sensory assessment labs and the farm’s market stand and CSA, as well as an on-campus field research site for demonstrating design, plot maintenance, data collection, and analysis.
GETTING STARTED
I began my work with a survey of the proposed field site at the farm. The space had previously been occupied for three years by a strawberry patch, which was moved after the 2021 growing season and occulted in preparation for planting in spring 2022. After taking measurements, I began making decisions about what I would actually grow for my trial.
After assessing the space and accounting for time to sow and plant, I settled on trialing two crops: early slotted radicchio and winter cabbage. Cabbage has always been one of my favorite vegetables, and I wanted to carry it forward into fermentation opportunities for entering freshman students in winter 2023. My love of radicchio began in my first program at Evergreen, in which we focused on the work of the Culinary Breeding Network to expand radicchio production and consumption in the Pacific Northwest. Growing early slotted radicchio allowed me the ability to study radicchio more closely and to share my love of leafy bitter vegetable with my peers in the fall.
FINDING A RESEARCH PARTNER
Because I was trialing two vegetables, requiring both significant field preparation and maintenance, I knew I wanted a work partner on the project. I found that partner in farm aide Andrew Luttinen, who agreed to help with the project. In turn, I agreed to assist Andrew in his summer research of buckwheat, which we located in the same field as my variety trial for ease of care and data collection. With this partnership in place, I was able to move forward with a design for the field.
THE GOALS
The first step in establishing the trials was to identify specific goals for each trial. Goals for the radicchio trial are to evaluate improved disease resistance to powdery mildew and downy mildew, improved pest resistance to aphids and slugs, resistance to bolting, and improved flavor. Cabbages will be evaluated for improved pest resistance to cabbage white caterpillars, slugs, and aphids, improved resistance to downy mildew and powdery mildew, improved overwintering (resistance to cold damage), and improved flavor.
The hypothesis for this experiment was that the chosen varieties of both cabbage and radicchio will perform better than conventional varieties in organic agriculture systems. Resistance to insects and evaluations of insect pressures were to be evaluated by observing damage and setting traps for data collection. As the season progressed, mildew damage would be assessed. Resistance to bolting and cold damage would be monitored, and variety tastings would be held to gather feedback from consumers, focusing on flavor, texture, color, and appearance. This feedback would then be evaluated and inform breeding decisions moving forward.
THE VARIETIES
The next step I took in planning my trial was choosing appropriate varieties for my goals and acquiring seeds. I chose varieties based on both the purported suitability of the variety to support the goals listed above and my own interests in seasonal extension for the Organic Farm’s market stand. I researched varieties available through various seed companies and then reached out to Laurie McKenzie at Organic Seed Alliance to facilitate procuring seeds that will meet my needs. I chose to trial ten varieties of early slotted radicchio exhibiting harvest dates ranging from 55-90 days after transplant and representing a variety of morphological variation. All the radicchio seeds are from OSA and are listed as follows: ‘Vesuvio’, ‘Mirabella’, ‘Pasqualino’, ‘Palla di Neve’, ‘Sorgente’, ‘Adige Precoce’, ‘Caravaggio’, ‘TVG1’, ‘Regina Rossa’, and ‘Vasari’.
Description of radicchio varieties. Image by Sarah Dyer.
The varieties of cabbage that matched my goals were acquired from a variety of sources and represent the work of OSA, Saltwater Seeds, Uprising Organics, Adaptive Seeds, and Territorial Seed Company. From Territorial Seed Co. I chose ‘Tundra’, I selected ‘January King’ from Uprising Organics, and from Adaptive Seed I chose ‘Winter King Savoy’. From Sam and Katie at Saltwater Seed Co., I acquired seed for two novel French cabbages and will be the first farmer to test these varieties in the United States; I referred to these varieties as ‘New French Green’ and ‘New French Red’. From OSA, Laurie McKenzie made a personal selection of the final variety in the trial, a variety developed by NOVIC that I called ‘NOVIC Purple’
Description of cabbage varieties. Image by Sarah Dyer.
THE DESIGN
Three replications of each block of varieties were to be planted in a design that was made to utilize both a north/south gradient and an east/west gradient. The east/west gradient helped to account for soil variability, wind, and weed pressure, and the north/south gradient accounted for a variation in shade across the field. Variety plots in each replication were randomized to provide the best range of possible variation in environments.
Cabbage blocks each contained six variety plots of ten plants each. Rows in each plot were spaced 18” apart in an offset or “chicken foot” pattern. Radicchio blocks each contain 10 variety plots of six plants each. Rows were spaced 18” apart, and plants were spaced 12” apart in-row. These blocks were then each replicated three times each. Finally, irrigation was spaced appropriately, with two drip lines laid in each bed in line with the rows.
Field map describing blocks and plots within the variety trial. Image by Sarah Dyer.
