Final report for GW25-005
Project Information
Edible flowers are an emerging market with an anticipated growth rate of 4.7% in the coming years (Pires et al. 2023). Countries in Europe and South America have tapped into this market as a secondary crop for vegetable growers, but North America has yet to fully capitalize (Fernandes et. al 2019, Pires et. al 2023). A lack of infrastructure and regulation has led to knowledge gaps in cultivation methods such as pest control. A popular sustainable approach for pest management is intercropping diverse species such as flowers and vegetables. Our proposed work will analyze the effectiveness of intercropping edible flowers with zucchini. Research Objective 1 looked at the impacts on yield and pest pressure of the edible flowers and zucchini when intercropped and the impact on the edible flowers' phytochemical profiles. Our partnership with a local producer, Dandelion Farms, provided a real-world setting for trialing this approach and an avenue for producer-level feedback. Research Objective 2 involved a sensory discrimination test in which we tested if intercropping affects the sensory components of the zucchini and flowers. Our first educational study, Education Objective 1, provided information on edible flower sales demographics in US farmers markets. Finally, Education Objectives 2 and 3 were dissemination methods for our research team to share our findings from the other objectives through educational materials such as extension articles, an open-access journal, and presentations to local communities. Our study's results on crop yields and pest damage while providing a secondary source of income will attract Western region growers to expand the North American edible flower market through intercropping.
Research Objective 1: Evaluated the impact that intercropping edible flowers with zucchini haon yields and pest pressure of the crops and phytochemical profiles of the edible flowers.
Research Objective 2: Evaluated if intercropping and monoculture production methods had an impact on sensory taste attributes.
Education Objective 1: Utilized a voluntary opinion study to assess demographics of the sale of edible flowers in farmer markets across the U.S.
Education Objective 2: Educated local growers, agricultural stakeholders, and the public about the benefits of edible flowers and intercropping them with vegetable crops through educational materials such as extension articles and an open-access journal article.
Education Objective 3: Educated local farmers, agricultural stakeholders, and the public about the benefits of edible flowers and intercropping them with vegetable crops through presentations.
Cooperators
- (Researcher)
- - Producer
Research
Research Objective One: Evaluated the impact that intercropping edible flowers with zucchini will have on yields and pest pressure of both crops and edible flower phytochemical profiles.
Implementing intercropping strategies is done to produce multiple crops together for the benefit that biodiversity can provide. Vegetables and other crops have been shown to experience higher yields when intercropped with flowering species (Balmer et al 2014). Often these species are grown as trap crops or cover crops which are worked into the soil at the end of the season rather than as another source of revenue (Pinero et al 2015). Our study helped to address the knowledge gap of it benefits exist when we intercrop these species with the plan to harvest both the vegetable crop and the flowers for consumption. This method took a typical added expense and turned it into an added revenue source.
Hypotheses: Hypothesis 1a. Zucchini intercropped with edible flowers will have an increase in fruit biomass at harvest. Hypothesis 1b. Edible flowers intercropped with zucchini will have an increase in the flower biomass at harvest. Hypothesis 1b. Phytochemical content will increase when edible flowers are intercropped with zucchini compared to those grown in monoculture. Hypothesis 1d. There will be a decrease in pest predation levels on both the edible flower species and zucchini when intercropped.
Research Design: The research plants were grown at Dandelion Farms in Fort Collins, CO (40.732821127050634, -105.07756848241353). The species grown were zucchini (Cucurbita pepo) and marigold (Tagetes erecta), which are of interest to our cooperating producer. The plants were grown in three treatments: a zucchini monoculture, a marigold monoculture, and zucchini intercropped with marigolds. The field was grown as a randomized complete block design (RCBD) with 3 block replications. Each block consisted of 2 rows of 3-4 plants depending on the space available. The monoculture crops will account for all the plants present in the block. In the intercropping treatments, zucchini will be planted in the two outside rows and the marigolds were grown in the middle row for each of their treatments. The seeds were sown in the Plant Growth Facility at CSU (40.57168754800878, -105.08105404372077) in early to mid-April to allow them time to establish. The seedlings of all treatments were transplanted into the field at the same time in early June.
Data Collection: Edible flowers and zucchini were harvested every 7 days. Availability of flowers between harvests will be important to retention of beneficial insects. At each harvest, we recorded the number of fruit or flowers harvested as well as the total biomass (grams) collected. Marigolds weights were recorded in the first two weeks, but not after as the collaborating farmer used them as cut flowers. During these regular collections, the counts of all zucchinis or marigolds harvested within a block werre pooled by species to provide one value for all research sample plants within that block.
Phytochemical Analysis: Total antioxidant and polyphenolic content were measured to serve as an indicator of possible health benefits that the flower material can provide. These compounds also serve as secondary compounds in stress response pathways which will indicate the plants’ relative stress levels. The retained flower material from each harvest were kept in a -80 °C freezer until processing for analysis. Methanolic extracts of this material were prepared according to published methods (Bao et al., 2018).
Antioxidant Analysis: We tested the total antioxidant content (TAC) by utilizing 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays. This colorimetric assay measured the ability of a given edible flower extract to scavenge DPPH radicals in solution based on the decolorization of that solution. Assays were incubated at room temperature and protected from light for 30 min before reading absorbance at 515 nm on a BioTek Synergy H1 Multimode Microplate Reader. Total antioxidant capacity was quantified based on a standard curve of Trolox, a potent synthetic radical scavenger, and expressed as Trolox equivalents per gram dry weight of flowers. Analyses was completed in triplicate.
Polyphenol Analysis: The total polyphenolic content (TPC) of our edible flower samples was analyzed using a Folin-Ciocalteu Reagent (FCR) assay. The TPC wascalculated against a standard curve of gallic acid and expressed as gallic acid equivalents. Analyses was completed in triplicate and measured at 765 nm on a BioTek Synergy H1 Multimode Microplate Reader.
Research Objective Two: Establish if there are noticeable differences in sensory characteristics between crops grown in a monoculture and those grown in intercropping systems
Hypothesis: There will be a significant difference in sensory characteristics of crops grown in monoculture and those grown in intercropping systems.
Neophobia, a fear or negative attitude towards new food can play a role in the acceptance of new products such as edible flowers. Sensory studies to introduce consumers to qualities of the food can help to reduce this and increase acceptance (Benvenuti 2021). How crops are grown has been observed to impact the phytochemical profile and sensory quality in products like basil (Ocimum basilicum) and tomatoes (Arenas-Salazar 2024, Korcok et al 2021). Tea (Camellia sinensis) intercropped with chestnuts (Castanea mollissima) had higher levels of amino acids and lower levels of bitter flavonoids (Wu 2021). Coffee (Coffea arabica) plants intercropped with mahogany (Khaya ivorensis) and teak (Tectona grandis) had higher sensory notes with more body, flavor, and balance compared to the monoculture treatment (Freitas et al 2020). This objective tested if this trend is similar in our research plants from Research Objective 1 by utilizing sensory discrimination tetrad tests. The first focus tested whether consumers can distinguish a difference between zucchini grown using intercropping with edible flowers and zucchini grown in monocultures. The second focus determined whether consumers can distinguish a difference between tea made from marigolds grown using intercropping with zucchini and grown in monocultures.
Research Design: Lee and Calvert executed this research objective at the CSU SPUR campus in Denver, Colorado. The researchers will recruited from the Greater Denver Metropolitan area and had 45 participants take place in the sensory discrimination tests for zucchinis and marigold tea. All recruitment and testing followed the IRB approval obtained by CSU’s IRB board in addition to the Western SARE approval board. This test was a tetrad design in which an untrained participant will be given four samples at a time with two of the monoculture-grown treatment and two of the intercropped treatment. They will be asked to group the samples into pairs based on similarity. Samples will be served according to a randomized Williams Latin Square design. This practice will be repeated twice, once for the zucchini, and once for the marigold tea as this was more likely to cause sensory fatigue. A mandatory time period of two minutes between test was provided to avoid sensory fatigue. The material used wa provided by our Research Objective 1.
Research Objective 1: Replication 1 was conducted in summer 2025. The results for total antioxidant and polyphenolic content showed that methanolic extracts of marigold petals exhibited total antioxidant capacity values ranging from 450 to 550 µmol Trolox equivalents (TE) g⁻¹ DW and total phenolic content ranging from 67–74 mg gallic acid equivalents (GAE) g⁻¹ DW with no significant effect from the cultivation method. Intercropping with edible flowers, such as marigolds, offers a promising way to generate additional income in a growing market.
The second replication for the study recently finished. We are in the process of analyzing the data from replication 1 (summer 2025; (e.g., flower and fruit biomass and pest pressure) ) and the most recent season (summer 2026; e.g., flower and fruit biomass, pest pressure, and phytochemical analysis).
Research Objective 2: Companion planting and intercropping are emerging cultivation practices due to their association with sustainability and pest management practices. Companion plants are often not a commodity, so exploring edible flowers as an intercrop rather than just a companion crop can provide another revenue stream for farmers. This study explored whether intercropping a known fragrant edible flower, marigold (Tagetes patula 'Sophia'), influenced the flavor profiles of zucchini (Cucurbita pepo 'Fordhook'), and phytochemical content (antioxidants and polyphenols) of the marigold flowers. Utilizing a sensory tetrad test, this research illustrated that participants could distinguish intercropped produce from those grown in monocultures. Crops grown in monoculture maintained their traditionally associated flavors. Zucchini grown intercropped were lighter in taste and more sour rather than sweet. Intercropped marigolds were noted to have lighter, herbal flavors. None of the impacts on crop flavor notes were perceived as negative, indicating that intercropping vegetables with edible flowers may be a viable way to grow produce.
Research outcomes
Consumers’ desires for new culinary experiences have provided avenues for the resurgence of less commonly known food crops such as edible flowers. With historical uses in civilizations such as ancient Rome and the Victorian era, this specialty crop has followed waves of popularity with a current increase in public interest. Edible flower research has focused primarily on understanding the health benefits and increasing shelf life. General information about the edible flower markets and trends, especially in the United States, is limited. Edible flowers have the potential to be a profitable supplementary crop, so understanding the characteristics of the US edible flower market is key to assisting growers in making informed decisions related to production and marketing. A national survey of US farmers’ market managers was conducted in Summer 2025. The survey asked managers to share their market demographics, the perceived status of the edible flower industry in their area, and their opinions regarding edible flower market characteristics. Approximately 1000 farmers’ markets were contacted, with 229 responses for a 22.9% response rate. Respondents located in urban (62.8%) and western (52.1%) regions were more likely to sell edible flowers in their markets. Southern (25%) and rural (25.9%) respondents were less likely to sell them. The most sold edible species by markets were nasturtium, calendula, marigolds, and pansies. Vendors who sold edible flower species alone accounted for only 3.5%, with vendors who primarily sold vegetables (47.7%) and vegetables and fruit (32.6%) as the most common vendor type, thus supporting claims of edible flowers sales primarily as supplemental income. When asked about the largest barriers to the edible flower market, managers shared that public knowledge (72.5%) and marketability (63.8%) were the biggest barriers to the expansion of this industry. The results of our study provide more insight into the US edible flower market. Moreover, it highlights areas of future research that can support producers interested in growing and expanding edible flowers sales and supplementing their current practices.
Companion planting and intercropping are emerging cultivation practices due to their association with sustainability and pest management practices. Companion plants are often not a commodity, so exploring edible flowers as an intercrop rather than just a companion crop can provide another revenue stream for farmers. This study explored whether intercropping a known fragrant edible flower, marigold (Tagetes patula), influenced the flavor profiles of zucchini (Cucurbita pepo), and phytochemical content (antioxidants and polyphenols) of the marigold flowers. Utilizing a sensory tetrad test, this research illustrated that participants could distinguish intercropped produce from those grown in monocultures. Crops grown in monoculture maintained their traditionally associated flavors. Zucchini grown intercropped were lighter in taste and more sour rather than sweet. Intercropped marigolds were noted to have lighter, herbal flavors. None of the impacts on crop flavor notes were perceived as negative, indicating that intercropping vegetables with edible flowers may be a viable way to grow produce. Methanolic extracts of marigold petals exhibited total antioxidant capacity values ranging from 450 to 550 µmol Trolox equivalents (TE) g⁻¹ DW and total phenolic content ranging from 67–74 mg gallic acid equivalents (GAE) g⁻¹ DW with no significant effect from the cultivation method. Intercropping with edible flowers, such as marigolds, offers a promising way to generate additional income in a growing market.
Education and Outreach
Edible Flower Sampling. Outreach Activity. July 2025. Windsor (CO) Farmers Market Event. 19 consenting participants. 1 child and 18 adults.
Participation summary:
The optional survey planned for Educational Objective One was distributed the growers within Colorado and other areas in the Western region in addition to growers organizations in early spring of 2025. After receiving only 5 responses in 2 months, the study was modified and we contacted managers of farmers’ markets at the suggestion of Extension collaborators. The following Educational Objective One is the adapted survey aimed at farmer’s market managers.
Education Objective One: Utilize a voluntary opinion study to assess edible flower sale demographics in U.S. farmers’ markets.
Hypotheses: Hypothesis 1a. The existence of edible flowers sales is impacted by the market type and location. Hypothesis 1b. The limited amount of currently available data and information could be a major barrier to increasing sales.
Objective Timeline: This survey was distributed from June to September. Survey inquiries were sent out in waves as responses began to come in and geographic gaps were identified.
Study Group and Sampling Method: The group contacted was managers of farmers’ markets across the United States. The goal was to receive a minimum of five responses per state and make sure each geographic region was covered, but some states were less represented due to a lack of participation.
Distribution Method: The survey was first distributed by contacting a representative of each state farmers’ market association in May and inquiring if they would be willing to share the inquiry with their member email chain. This inquiry will contain the link to the survey and an IRB-approved recruitment letter/email detailing the objectives of the survey and the contact information. When the method did not yield distribution with the exception of three states, distribution was instead performed by randomly reaching out through individual market contacts.
Survey Design: A survey was developed based on preliminary consumer edible flower survey results and feedback from Extension specialists. The survey was distributed electronically (Qualtrics LLC, Provo UT USA). The survey questions included: (1) zip code associated with the market; (2) regional land-use classification of the market location (i.e., rural, suburban, or urban); (3) market style classification (i.e., traditional, producers’ only, year-round, pop-up, hybrid, virtual); (4) estimated percentage range of vendors who sold any type of flowers (e.g. 0 to 20%, 20 to 40%); (5) presence of vendors who intercrop food crops and any flowers; (6) level of perceived edible flower market interest; (7) and if edible flowers are sold at that market. In Questions 2, 4, 5, 6, and 7 were multiple choice questions, allowing respondents to provide a single choice. For Question 3, market classifications were created based on observed market classification trends and definitions were not provided to the respondents and they were allowed to select more than one classification. Question (7) was a skip logic question; if the respondent answered “no” to edible flowers being sold, they were directed to the final three survey questions. The first required question asked which barriers impact the presence of edible flower sales. The second and third questions were optional, asking respondents to rank edible flowers of interest and an optional free-response feedback opportunity. If the respondents answered “yes” that edible flowers were sold at their market, they were surveyed as to what specific edible flower species were sold and what other crops the edible flowers vendors sold. After answering these two questions, the “yes” respondents were also directed to the last three questions that the “no” respondents were asked. With the exception of the market’s zip code, all the responses were self-identified by the survey respondents. The survey was between 10 and 12 questions depending on the skip logic question (7).
Education Objective Two: To educate local farmers, agricultural stakeholders, and the public about the benefits of edible flowers and intercropping them with vegetable crops through educational materials such as extension articles and an open-access journal article.
Hypothesis: Education materials provided through CSU Extension and a horticulture open-access journal will have an impact on the access that the public and farmers have to information about edible flowers.
Target Audience: Master gardeners and extension agents can serve as direct links between research institutions and the public. Our target audience was these educators as well as the public and producers in the US who have access to Extension articles and journals online.
Open-Access Journal: We published our findings from Education Objective 1 in a horticulture-based open-access journal. Lee and Miller are members of the American Society of Horticultural Sciences and thus submitted to the society’s journal, HortTechnology. This journal is well regarded in the Horticulture field and is open access, allowing the science community and public alike access to our findings.
Extension Articles: CSU Extension currently has one fact sheet on edible flowers that details general edible flower knowledge such as its history, uses, and which flowers are edible. The fact sheet was edited in the summer of 2025 to provide additional clarity and additional species that are edible. During the summer of 2025, Lee also served as an Extension intern for CSU on another edible flower research project. Details and results of the studies were highlighted in interviews published by CSU Office of Engagement and Extension and in Greenhouse Management magazine. One additional article was coauthored with CSU Office of Engagement and Extension where we wrote how to safely grow and eat 12 edible flower species with the article being adapted from growing cards Lee created.
Education Objective Three: To educate local farmers, agricultural stakeholders, and the public about the benefits of edible flowers and intercropping them with vegetable crops through presentations.
Target Audience: It was determined that educating the public is just as instrumental as educating growers who may have interest in growing edible flowers. Results of Educational Objective One showed that an educated and larger consumer base is needed for the edible flower industry to expand. We educated about edible flowers to a variety of audiences including industry stakeholders, growers, Extension agents, and the public.
Edible Flower Tabling: CSU has multiple channels for community outreach. One is that Extension agents man tables at weekly farmers’ markets to provide resources and answer community questions if possible. Attendance at one of these markets was performed to assess public taste preference of different edible flower species. This tabling was mirrored at the Second Saturday event at the CSU SPUR campus.
Presentations: Presentations were planned to distribute the results of our research and educate about edible flowers. One presentation was invited by a survey participant and a talk was given to the Wyoming Food Coalition. Another presentation was given to industry members and stakeholder at an industry Expo. Poster presentations also were planned to showcase research results and engage Extension agents.
Educational Objectives One and Two:
A peer-reviewed journal article was written about the survey results of Educational Objective One. The article, "The US Edible Flower Market through the Farmers’ Market Lens", was published in HortTechnology in May 2026. Our study provided further insight into the US edible flower market. Urban and Western markets had higher interest in and reported sales of edible flowers compared to rural and Southern markets. The mostly commonly selected vendor type for those who sold edible flowers were those who sell vegetables alone or vegetables and fruit together. As with any developing industry, overcoming perceived barriers is paramount to success. With our survey, marketability and public knowledge were documented as the biggest barriers and provide direction for critical work that can be done by educating the public on edible flowers to facilitate industry expansion.
Educational Objective Two:
Two interviews that covered edible flower education and some research results were published in Greenhouse Management (February 2026) and the CSU Office of Engagement and Extension (November 2025). One Extension article was coauthored about safe growing practices and culinary applications of 12 edible flowers (November 2025). The information gathered for the Extension article was adapted into growing cards that could be used in industry or nursery settings.
Educational Objective Three:
Two tabling events occurred to present community members with information about edible flowers and to test their preference for different edible flowers. At the farmers' market tabling, the flavor of echinacea was preferred over dahlia and violas. At the Second Saturday tabling, adults preferred dahlia over echinacea and marigolds. Children liked echinacea more than dahlias and marigolds. When asked about what was of highest interest when purchasing produce, children and adults alike stated quality, then health, then price. A variety of colors and species was the preferred packaging style for edible flowers and $7.98 was the anticipated/would pay price of a prepared edible flower package like one you would find in a store. The participant size was 39 children and 51 adults, so this data was helpful, but not enough to justify a publication.
Two poster presentations were performed for this objective. The work performed at the tabling events and the growing cards developed for Educational Objective Two were the topics displayed for the CSU OEE Annual Forum Extension Intern Poster Session. This poster session had over 100 attendees from the CSU Extension community. The second poster presentation took place at the Colorado State University Graduate Student Showcase in November 2025. The poster shared the results of Educational Research Objective One with roughly 200 attendees from the showcase. The audience was students and other members of academia primarily.
Three presentations account for the remainder of the outcomes. The first was given to a small live audience for the Wyoming Food Coalition. This presentation covered the survey results and maintains accessible to members of the coalition and anyone who finds the organization website. The second presentation was given at the ProGreen Expo. This expo is predominantly attended by horticulture industry members. The presentation highlighted edible flowers in general and the work performed as part of this grant. Roughly 50 people were in attendance. The final presentation will occur in December 2026 at the Great Lakes Expo in Michigan. This is an invited talk generated by the recently published farmers' market survey journal article in HortTechnology.