The Blossom End Rot Toolkit

Project Overview

Project Type: Research and Education
Funds awarded in 2023: $312,490.00
Projected End Date: 03/31/2026
Host Institution Award ID: G288-23-W9981
Grant Recipient: Oregon State University
Region: Western
State: Oregon
Principal Investigator:
James Myers
Oregon State University
Matthew Davis
Oregon State University

Information Products


  • Vegetables: tomatoes


  • Crop Production: drought tolerance, fertilizers, intercropping, windbreaks
  • Production Systems: dryland farming

    Proposal abstract:

    Limited water availability is a major issue in the western US. Leap et al. (2017) demonstrated profitable dry farmed tomato production in coastal California, and suggested that dry farmed tomatoes have improved flavor. The WSARE project, “Production and Marketing of Dry Farmed Tomatoes in Oregon” has demonstrated that dry farm tomato production is possible in the Willamette Valley using blossom end rot (BER) resistant varieties and grafting. However, many BER resistant varieties and grafted tomatoes were rated lower than ungrafted BER susceptible tomatoes like 'Early Girl' in overall preference during sensory evaluations.

    Farmers want to grow flavorful tomatoes with low rates of BER. This project will create a “BER Toolkit” for farmers. All of these tools are based on Saure’s hypothesis that BER is the result of a sequence of luxurious growth followed by severe stress (Saure, 2014). We will test the effectiveness of the following "tools":

    • Sheltering
    • Soil amendments 
    • Decreased in-row spacing
    • Deficit-irrigating transplants prior to planting

    The toolkit will be disseminated to farmers through field days, publications, and videos made available on the Dry Farm Collaborative Youtube page. Farmers will understand all of the benefits and drawbacks of each “tool” and will be able to test a suite of them. A diversity of vegetable producers will be able to apply the principles of the BER toolkit to their farms whether irrigated or dry farmed.

    Determining how to successfully dry farm ‘Early Girl’ tomatoes in the Willamette Valley will open up a high value market while reducing water use and increasing in-stream flows. It will eliminate the need for costly irrigation systems, increase profitability, and reduce greenhouse gas emissions. It will allow farmers on lands with no or limited irrigation rights to grow profitable crops with little to no risk, thereby increasing profitability and quality of life.

    Project objectives from proposal:

    1. Test and demonstrate a suite of "tools" for mitigating blossom end rot (BER) in dry farmed tomato production, all based on the Saure Hypothesis that BER is caused by a sequence of early season luxurious growth followed by severe stress.
      1. Tool 1: Sheltering by intercropping with dry farmed corn to reduce drought stress.
      2. Tool 2: Reducing soil amendment applications to reduce early season luxurious growth.
      3. Tool 3: Decreasing in-row plant spacing to reduce early season luxurious growth. 
      4. Tool 4: Pre-stressing seedlings during nursery production to produce transplants with "Drought Stress Memory."
    2. Determine effects of tools on other measures of yield, fruit quality, wind run, cost of production, and plant health.
    3. Determine the interactive effects between the different tools.
    4. Demonstrate the effectiveness of the BER toolkit when implemented on farms.
    5. Educate farmers and agricultural professionals to different theories of the cause of BER in tomatoes.
    6. Educate farmers and agricultural professionals to the components of the BER toolkit (including grafting), how they effect crop production, and how they interact.
    7. Promote dry farmed tomatoes and educate the consumers, retailers, wholesalers, and other marketers to the value of dry farmed tomatoes, including environmental benefits and culinary value. 
    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.