I have a Braeburn apple tree that is about seven years old. It puts on apples but they remain small. Last year I put tree spike fertilizer around but this year they don’t appear to be getting any bigger. Any suggestions?
Douglas County Oregon
Getting apples to size well is dependent upon several issues. The first is all about leaving the number of apples on the tree that the tree vigor can finish properly. That means thinning to single fruit on spurs that are six inches apart in late May so the tree is not over burdened. If you leave clusters of fruit the apples will never reach commercial size.
The second issue to achieve proper fruit size is to water the tree so it is getting about1.5 inches of water a week. You can measure this with a rain gauge in the area around the tree that catches the sprinkler output, or if you have a drip system you should be putting on about 20 gallons of water a week through each emitter.
Keeping a tree vigorous will also require fertilization and the proper pH. Fruit trees like a pH of 6 to 6.5. If your soil pH is lower than 6 you should be adding 3-5 lbs of lime around the tree drip line depending on how acidic your soil. Trees also need some nitrogen for growth of the tree and fruit, add about 2-3 lbs. of urea per tree per year or 3-4 lbs. of 16-16-16 if you need a complete fertilizer.
Try taking these steps and fruit size should increase significantly.