One of the most common questions home fruit growers ask is, “Why didn’t my tree grow any fruit?” There are many possible reasons for poor fruit set, including:

• Age of the tree. Dwarf apple trees will bear fruit 2-3 years after planting. 
  Pear trees could take up to 10 years.
• Shade, because only a tree in full sun produces fruit.
• Biennial or alternate fruit bearing years.
• Late spring frost or freezing flowers.
• Cold or rainy weather during bloom.
• Insects and disease.
• Lack of a compatible cultivar for cross-pollination in species 
  that are not “self-fruitful.”
• Heavy pruning.

With most fruits, flowers that appear in early spring begin as buds that formed during the previous year. Flowers of many fruits bloom during early spring and can be damaged by frost. If temperatures fall below 30 degrees F when the flowers are forming, some or all may be killed, reducing fruit set. This is especially true with peaches, which are marginally hardy in Minnesota.

Left to its own devices, an apple tree will set too many fruits, too many for best quality, that is. Excessive fruit set reduces flower bud formation for the next season and results in biennial or alternate bearing—a heavy crop of small-sized fruit one year and little or no crop the next. Thinning within the month after bloom helps prevent alternate bearing.

Pollination is essential for fruit set. Insects carry the pollen from flower to flower. Bees, like most people, do not like to work in rain, wind, and cool temperatures; therefore, pollination may fail even though all other factors are okay.

Apples, pears, apricots, and most plums, are not self-fruitful. They require cross-pollination from another variety for fruit to form. If you plant two trees that are the same cultivar, they will not pollinate one another. For example, two Honeycrisp apple trees will not pollinate each other, but a Honeycrisp and a Cortland will. Plant all fruit trees used as “pollinizers” within 200 feet from each other, to ensure successful pollination. 

Apple trees produce most of their fruit on spurs (short, stubby shoots) that form on two-year old and older wood. Heavy pruning can remove spur bearing branches and forces the tree to rebuild structure instead of fruit. Plus, excessive pruning can produce upright, vegetative growth with few flower buds.

There is no single reason for a low yield but rather a combination of all the reasons mentioned. Through careful monitoring and patience, home orchardists can improve their chances of enjoying a successful and rewarding fruit harvest.