Asked November 28, 2022, 12:52 AM EST
I have both an eight year old Newton Pippen and an eight year old Granny Smith apple trees. I harvested apples and find that the apples have spots that appear to me to be bitter pit. There are more spots away from the stem and the spots increase after the apples have been picked. I do not taste the spots being bitter. There is only mild corky material under the spots. I do not think the spots are from stink bug attacks.
I had the soil tested and the results are posted:
Oregon State University Extension
Douglas County Master Gardeners Soil Test Lab
Results of Soil Analysis
Client: November 12, 2022
Soil Texture: 47 % sand 40 % silt 13 % clay
The approximate classification is: a loam soil.
Humus: The humus concentration score was 0
This level is considered very low See comments on next page.
pH: The pH of the sample was 8.0 SMP buffer value: not measured
This soil is considered alkaline. Moderate range: 6 - 7
Nitrogen: The NO3-nitrogen level was 5 ppm, or 0.2 lbs/1000 sq. ft.
This level is considered low. Moderate range: 40 - 99 ppm
Phosphorus: The phosphorus level was 25 ppm, or 1.1 lbs/1000 sq. ft.
This level is considered moderate. Moderate range: 20-40 ppm
Potassium: The potassium level was 150 ppm, or 6.9 lbs/1000 sq. ft.
This level is considered moderate. Moderate range: 150-250 ppm
Calcium: The calcium level was 2800 ppm, or 128.6 lbs/1000 sq. ft.
This level is considered high. Moderate range: 1000-2000 ppm
Magnesium: The magnesium level was 5 ppm, or 0.2 lbs/1000 sq. ft.
This level is considered low. Moderate range: 15-40 ppm 60-180 ppm
I had planned to add lime because I read that a lack of calcium will cause bitter pit. However the soil test says I have high Calcium. I know a high pH prevents absorption of Calcium but my soil is only pH 8.0 so that is not high enough to prevent absorption.
Can you tell me what fertilizer I should use on these trees?
Douglas County Oregon