Why do leaves turn yellow?
Written by
Paul Reynolds
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Yellowing leaves on blueberries often indicate soil pH imbalance, which can restrict nutrient uptake by the plant. When veins remain green and leaves are yellowing, it's called chlorosis. It may occur above pH 5.0 and will stop the uptake of iron. I have corrected this problem (chlorosis) in my plants using applications of iron sulfate. I periodically test to make sure my berry bushes remain healthy.
Immediate Treatment
- Apply iron sulfate (1 tbsp per gallon)
- Retest pH after 72 hours
- Water deeply to activate amendment
- Repeat if pH remains above 5.0
Preventive Maintenance
- Test soil monthly with digital meter
- Use rainwater instead of tap water
- Apply pine bark mulch quarterly
- Avoid alkaline amendments like wood ash
Use iron sulfate as a soil application around the root zone. This is an immediate way to lower pH while providing lacking iron. My plants greened up in 10 days after application. For serious cases, reapply weekly until new growth is growing well. Always water in thoroughly after treatment.
Use rainwater collection systems to control acidity. City water often has a pH above 7.0, which only compounds the pH issue. I built barrels that naturally lowered the pH of my water to 5.5. That mitigated the drama in soil conditions better than any chemical approach.
Mix amendments with acidic mulches, such as pine bark, to enhance soil quality. A 2-inch layer helps regulate soil temperature while slowly acidifying it. My plants have completely recovered after I added mulch to the amended soil, and they now produce deep green leaves throughout the year.
Read the full article: How to Grow Blueberries in Pots Successfully
