Onion field

Essential Nutrients for Onion Yield and Quality

Yellow Onion Yield & Storage Results: Calcium Thiosulfate vs Calcium Chloride

CaTs® is a 100% water soluble calcium with a 0-0-0-10S-6Ca analysis. CaTs applied through the irrigation system can supply the necessary calcium and sulfur at critical growth and uptake times. Onion trials conducted in the PNW have show increased yield and improved storability.

A study conducted in Washington was able to demonstrate the increase of yield and storability of CaTs. The study included treatments of CaTs and CaCl2 based fertilizers and found that yield and storability was improved. Overall, the CaTs treatments increase yield and had reduced weight loss while in storage for 6 months.

  • Chart showing yield increase when using CaTs vs CaCl2

    * Split applied at bulb swell and two additional applications every 3 weeks

  • Chart showing less onion shrink over time when using CaTs
Drip irrigation tubing

Key Factors Driving Onion Yield and Quality Results

  • Both calcium and sulfur are needed throughout the growing season
  • Sulfur is needed when the plant is actively growing and utilizing nitrogen
  • Peak calcium uptake occurs at bulb initiation
  • Applying CaTs through the irrigation system 10-14 days after bulb initiation can supply much needed calcium and sulfur at critical times
CaTs Badge Small 2

Additional Benefits of Calcium Thiosulfate and Sulfur in Onion Production

Calcium

  • Improves cell wall strength
  • Increases disease resistance
  • Helps reduce heat stress
  • Reduces NH4 volatilization losses when applied with urea fertilizer

Sulfur

  • Increase yields
  • Increase pungency and flavor
  • Improves nitrogen use efficiency
  • Serves as structural component of proteins