This website no longer supports Internet Explorer 11. Please use a more up-to-date browser such as Firefox, Chrome for better viewing and usability.

Crop load regulation (thinning) in organic apple growing


The thinning of fruit until the physiologically optimal number of fruit is reached is essential in fruit cultivation to achieve regular yields of a good, storable quality. In organic farming, growth regulators are not permitted; thus, this project aims to find suitable alternative methods that adhere to organic farming regulations.

Detailed Description

We test different different natural products (mostly dissecants) and physical methods (e.g. rope thinner, or shadow nets) for their thinning efficacy – alone or in various combi-nations, or application dates. Usually we apply the test methods on 4-6 cultivars with at least 2-4 replicated plots of 18 trees per cultivar. We apply the products with a commer-cial axial sprayer to achieve practical circumstances. We count a) flower set before treatment, b) fruit set after treatments before June drop, c) fruit set after June drop; d) fruit set before harvest, e) negative side-effects such as russeting or phytotoxicity; f) return to bloom in the following spring. Before practical recommendations are made, the method is tested for about 3 years.

Financing/ Donor
  • BLW
  • private companies
Project partners
  • Different universities
FiBL project leader/ contact
FiBL project staff (people who are not linked are former FiBL employees)
Role of FiBL

Project management

Research area
  • Cultivation Technique Fruit & Wine crops (Department of Crop Sciences)
  • Training (Department of Extension, Training and Communication)
FiBL project number 15038
Date modified 12.11.2019