Sorrel Pesto: The Positive Implications of Sorrel as a Substitute for Basil in Pesto Production

Final report for FW16-033

Project Type: Farmer/Rancher
Funds awarded in 2016: $19,710.00
Projected End Date: 03/31/2019
Grant Recipient: Green Skies Vertical Farm
Region: Western
State: California
Principal Investigator:
David Ceaser
Green Skies Vertical Farm
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Project Information


Green Skies Vertical Farm is an urban farm in Oakland, CA growing herbs, microgreens and salad greens.  The farm began operations in 2013 and soon began growing sorrel in its hydroponic system.  Sorrel was added as an ingredient in salad mix and soon after we expanded its cultivation to sell it as its own product.  Sorrel cultivation was expanded within the existing hydroponic system and begun in soil based cultivation.

Sorrel was an incredibly successful crop and gave very high yields both in hydroponic and soil based environments.  Additionally, it was incredibly popular among kids.  We began to market it as 'kid spinach' and sales took off.  Soon it became our leading crop for our very small farm.  Seeing the success of sorrel at our farm and the lack of sorrel in the marketplace, we decided that other farms should also produce sorrel.

The work on this grant focused on four main areas.  First was surveying the general public about their familiarity with sorrel and for those unfamiliar with it, getting their reaction to this unique salad green.  The second was understanding how people are currently using sorrel and documenting their use.  The third was contacting local farms and gardeners and understanding a bit more about who is cultivating sorrel and how they are currently using and marketing this product.  Finally, fourth was working with interested producers to cultivate sorrel on their farm and gauge the impact that it had for their operations.

Project documentation can be found at this website:

Project Objectives:

These are the objectives that should have been completed to date with comments regarding each.

1. PI will design informational materials about sorrel for local pesto producers consisting of nutritional
information and benefits of using sorrel instead of or in conjunction with basil. Benefits for the pesto
producer including reduced labor (less processing work), year round availability, and reduced costs. An
initial survey would also be designed to understand pesto producers' level of experience with sorrel prior to
participation in this project. Technical advisor will help with design of survey (May 2016­ July 2016).

This has been completed.  See two attachments in the summary section.

2. PI will set up meetings with 5 local pesto producers to discuss using sorrel for their pesto, provide them
with promotional materials and free samples of sorrel to try in their facility. PI will listen to their priorities
and concerns regarding their pesto operation and with help of technical advisor, will design an exit survey
to be implemented at the next stage. (August – November 2016).

In the 2016 report on grant progress, PI noted the following: “PI has met with 3 local pesto producers and is in the process of arranging two more meetings w local producers.  Locating pesto producers and getting them to participate has been more difficult than expected.  PI is considering offering a gift certificate or other reward for participation in the grant research.”

Getting pesto producers to participate in the grant research continued to be more difficult that expected.  Based on that and in conjunction with a very positive response to sorrel among customers and the general public, PI requested a modification in the grant scope as described in this e-mail to NIcole Hansen on 8/30/17:

The original focus of our grant was on introducing sorrel to pesto makers as a substitute for basil.  From our initial work and the response from pesto producers so far, the interest is only luke warm.  At the same time, we have been doing work to promote sorrel consumption in general and the response has been very high.  We feel that developing this aspect of the research and different ways sorrel can be used would be much more valuable to the farmers we will work with and the readers of our work.  The main components of the grant work will be the same except that our second set of interviews and research would focus on customer uses for sorrel in general.  Additionally, I will include this (in more detail) in the grant report to explain the shift in focus.”

This modification of the grant was approved by Rhonda MIller and thus changes items 3-5 to focus on interviews with individuals.  Based on this modification, PI conducted interviews with consumers at several events in the San Francisco Bay Area.  Short Interviews were held with anyone who was interested and consisted of the following questions:

  1. Have you ever eaten sorrel before?  IF yes, how was it prepared? (participant could then eat fresh sorrel and interview ends).  If no, continue to questions 2 & 3.
  2. If participant hasn’t had sorrel previously: Please tell me what you think it will taste like based on its’ appearance?  
  3. Participant tastes sorrel and gives feedback on the taste in three ways- 1) if they enjoy it, 2) what it tastes like to them and 3) how they can envision it being used.

Here is a link to a folder with some of the videos from a tasting event at the Exploratorium museum in San Francisco.

Finally, PI has documented sorrel sales on PI farm to show how important a component of sales sorrel can be for a small operation.

3. PI will implement exit survey with 5 pesto producers to obtain as much information as possible regarding
the use of sorrel in their business. Based on this feedback, PI will refine informational materials and in
preparation to contact a second set of pesto producers. (December 2016­ January 2017)

This element was partially completed but then aborted due to the modification in scope of the grant.  All completed survey materials will be included in the grant report (item 6).

  1. Using the refined promotional materials, PI will meet with an additional 10 pesto producers. (February - June 2017).

This element was aborted due to the modification in scope of the grant.


  1. Conduct exit surveys/ get feedback from second set of pesto producers. (July-August 2017)

This element was aborted due to the modification in scope of the grant.

  1. Pesto producer documentation summary- PI will create a report that documents all information gathered and analyze data collected to date. It will also outline the perceived opportunity for farmers cultivating sorrel in the scope of pesto production. Technical advisor will assist with data analysis. (August 2017 – November 2017)


Here are some highlights from the data collected so far.  All results will be incorporated into the final report.

131 mini interviews were conducted and the results are shown here:

A quick summary of some of the results to date.  We will continue to conduct surveys at different public events and add that data what we are collecting to have a more complete picture:

  • Most people were unfamiliar with sorrel- had never tasted it or couldn’t remember having tasted it.  88% had never tasted while only 12% had
  • Of 98 respondents who scored the flavor, the average score given was 7.73 on a scale of 0 to 10.  0 means that they dislike, 5 is a neutral score and 10 being absolutely loving it.  Only the people who were tasting it for the first time gave a score.
  • Most people who had never tried it before assumed it would taste like lettuce, spinach, grass, arugula or maybe basil.  Many people assumed it would be flavorless, watery or bitter.  Almost everyone was very surprised with how it actually tastes.
  • For some people the initial “flavor shock” was too much.  The acidity was too much for them to handle.  Once they got over the initial shock, they enjoyed the flavor.
  • Many people really enjoyed the flavor but wondered how to use it.
  • Some of the things that they were reminded of when trying sorrel- sour apple, mango, unripe apricots, warheads (candy), sourgrass, rhubarb
  • Quotes-
    • “it reminds me of being back in Africa”
    • “the flavor makes me smile”,
    • “no shit !”
    • “I rate this a 5 by itself but an 8 with a partner”,
    • “delicious... romaine is child while sorrel is the cool uncle”


PI and staff has also collected recipes for sorrel use to be shared with other farmers.   Recipes collected to date can be found here:


Economic Viability: Green Skies Vertical Farm

Sorrel has been a very important part of the income of Green Skies Vertical Farm.  Because sorrel is high yielding per area, grows year round and is virtually pest and disease free in our climate, it is a continuous source of income for our farm.  

For the period of 2014- 2018, sorrel has been our best selling crop, in terms of total revenue.  During this period, sorrel sales have accounted for 15.9% of sales, slightly outselling our salad mix 15.7% and third, spearmint bunches, 13.8%.  Additionally, sorrel is a part of our salad mix, making up approximately 25% of each bag, so theoretically, additional revenue could be attributed to sorrel.


  1. Farmer Survey Design: PI, with help of technical advisor, will design a pre and post survey regarding farmer history with sorrel, cultivation and sales history, problems experienced, knowledge about, etc. (December 2017- January 2018)

A survey for farmers is being drafted by PI with the help of project Technical Advisor.  Survey can be seen here:

  1. Educational Outreach- Farmers (February- June 2018): PI will meet with area farmers at local/ regional farmer's markets or by visiting their farms. Initial survey will be conducted with farmers and the opportunity for sorrel production will be shared with farmers. Contact information will be gathered for a follow-up survey 6 months later.

The survey described in the previous section was distributed in the following manners:

  • Survey distributed online via UCANR e-mail blast (through technical advisor)
  • Survey was e-mailed to additional farms in Northern and Central California that are not part of the e-mail blast.
  • PI visited area farmer’s markets and promoted project with farmers at these markets.


  1. Farmer Follow-up (September – December 2018) Conduct exit survey with farmers to see if they have implemented sorrel production and why or why not. Survey will also look at economic, social and environmental impacts for those producers who did cultivate sorrel.

PI was in touch with several farms who expressed interest in cultivating sorrel but was not able to get confirmation from farms if sorrel was actually planted and if so, what the results were.  PI hopes to continue receiving information from farmers and will update the website and documents with any new information. 


  1. Final project report (January – June 2019) PI and advisor will analyze data. PI will create a final report and short YouTube video documenting all information from project. Advisor will publicly report study results through UC Cooperative Extension.

Final report will be made available on project website in addition to other project documents (  A link to the project website will be shared via e-mail blast by UC ANR.   All survey respondents will also be contacted with the project results.  


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  • Rob Bennaton


Research results and discussion:

This project was not a traditional research project.  It contained some elements of market research and those elements are discussed in the project slides (available for download) and the project report available on the project website:

Participation Summary

Research Outcomes

No research outcomes

Education and Outreach

3 Curricula, factsheets or educational tools
4 Other educational activities

Participation Summary:

50 Farmers participated
Education and outreach methods and analyses:

Outreach to the general public was done at numerous events- Maker Faire, Exploratorium, Mandela Market Store and other non-planned events. This outreach was educational about sorrel, its uses, etc.  Outreach always included tastings.  More than 130 individuals were reached in these methods.

Outreach to farmers was done in person at farmer's markets and online via our survey.  E-mail distribution of our project website and information was done via e-mail blast.   More than 50 farmers were contacted.

3 Farmers intend/plan to change their practice(s)

Education and Outreach Outcomes

Recommendations for education and outreach:

Communication with farmers was more difficult than expected and getting farmers to incorporate a new crop into their crop plan is very challenging.  Having our economic data and marketing materials ready to go earlier in the process would have likely made more farmers motivated to incorporate sorrel as a new crop.

10 Producers reported gaining knowledge, attitude, skills and/or awareness as a result of the project
Key changes:
  • Knowledge: Ways to market and promote sorrel

  • Knowledge: Uses of sorrel

  • Knowledge: Methods of sorrel cultivation

  • Knowledge: What is sorrel

Information Products

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.