Fruit Thinning Pointers

By Charles Davis, UC Master Gardener

1. Thinning is done to avoid: (1) alternating bearing years, (2) breakage of branches due to excessive crop, and (3) to allow for better air circulation around the fruit to prevent disease (especially if the fruit is touching).
2. Trees not normally needing fruit thinning: cherries, figs, pomegranates, citrus and nut trees.
3. Trees normally needing thinning: Stone Fruits:  peach, nectarine, apricot and plum; Pome Fruits:  apples, Asian pears, and most European Pears.
4. Thinning should always be done if the crop is excessive, relative to the vigor of the tree.
5. Thinning can be done from right after bloom until just before harvest---it is best to wait until after any natural drop occurs (generally early April for early ripening fruit to mid-May for late ripening fruit). Waiting too long reduces the tree’s vigor which may result in a “light” bearing year the next year because the tree needs to recover.
6. Stone fruit are best pruned when the fruit is ¾-1” in diameter; pome fruits at ½-1” in diameter.
7. Peaches and nectarines: thin to about 5-7” apart.  Remove all “doubles” and small, disfigured or damaged fruit.  The larger distance is required by the large size of the fruit.
8. Apricots, plums, pluots and apriums: apricots and apriums---3-5” apart; plums and pluots---4-6” apart.  The smaller distances reflect the relative sizes of the fruit.
9. Apples and pears: normally thin to one fruit per cluster.  If crop is light you can leave two per cluster.  If crop is heavy, ensure the fruit is no closer than 6-8” apart.
10. Quinces do not require thinning; persimmons are often not thinned, but thinning increases fruit size.
11. Thinning should be done carefully---do not simply pull the fruit off or you may end up pulling off the entire spur. Instead remove by twisting or (especially for apples and pears, which are hard to remove) cutting with clippers.
12. Thin by hand, or if that is impractical or dangerous (because of the size of the tree) by pole.

References

Ingels, Chuck A, Pamela M Geisel, and Norton V Maxwell. 2007. The Home Orchard. Oakland, Calif.: University of California, Agriculture and Natural Resources