Boron deficiency made worse by
- Sandy soils
 - Alkaline soils
 - Soils low in organic matter
 - High levels of nitrogen
 - High levels of calcium
 - Cold wet weather
 - Periods of drought
 
Boron is important for
- Carbohydrate metabolism and protein synthesis
 - Calcium movement within the plant
 - Improved yield and storage quality
 - High requirement
 
Yara recommended fertilizers for Boron
YaraVita® POWERBOR™ Ca
Onion: 1½ to 2 quarts/acre as soon as there is sufficient foliage to intercept spray. A second application may be made at the same rate 10 to 14 days later. Water rate: 5 to 20 gallons/acre.
Read more about YaraVita® POWERBOR™ Ca