Xtremehorticulture of the Desert: Thinning Fruit to Make Remaining Fruit Larger

Tuesday, May 25, 2021

Thinning Fruit to Make Remaining Fruit Larger

Thinning fruit must be done to get the remaining fruit larger. It's also done to prevent limb breakage from all the weight of mature fruit! Its best done as soon as possible, when fruit is still small. Usually when fruit is 1/2 inch or smaller.

Peach fruit is thinned to allow the remaining fruit larger and prevent limb breakage. Usually only three or four fruit remain after thinning. How many fruit should be removed?

The same branch after thinning is done. Thinning can also be helped when pruning is done by making branches that are too long, shorter.

The fruit tree makes a set amount of “food” each year. It either goes into growth or fruit production. When thinning begins, the fruit should be small. If done when the fruit is larger then this “storage food” is removed from the tree and wasted. Thinning larger fruit and this green fruit is dropped to the ground takes the energy the tree invested into fruit production and puts it into the soil. Bugs are not a problem for the tree provided thinning is done early.

Apples and pears form fruit in clusters of typically five to six fruit. All but one is removed from each cluster. The remaining fruit was the largest in the cluster.

One fruit remains after thinning apples and pears. It is usually the largest in the cluster, the "king"

When thinning is done early the fruit can be dropped on the ground and left to rot. When thinning is done later and close to maturity, the fruit should be collected and not left to rot in the field or it will attract some damaging insects (eg stink bugs, fruit beetles, and fruit flies) and rodents.

Although it is thought that it is never too late to thin fruit, it is best done as early as possible. But if fruit is close to maturity, it is more attractive to pests that may go after ripe fruit in your orchard. Decomposers that focus on immature fruit is different from those that prefer mature fruit. Your trees also have mature fruit. So which mature fruit is okay for mature fruit decomposers to have?

Generally speaking, fruit thinning starts when the fruit is about ½ inch. For early producing varieties thinning is started early. For peaches growing in Las Vegas thinning can begin as early as the first week of March for the early flowering varieties and as late early May on later varieties.

Look for thinning to begin about March 1 on peaches and some varieties of apricots; later varieties are thinned later
Start to schedule thinning when fruit is about “thumbnail” size.
The timing for later varieties weekly as the fruit reaches this size. So I would suggest weekly thinning of fruit once it begins. Young apples may produce fruit for thinning until June or later!

Chemical sprays to thin fruit are available for professionals for apples and pears but peaches, nectarines and plums are done by hand.

June Drop

There is a term floating around for fruit trees called "June drop". June drop refers to the dropping of fruit by the tree if it is not pollinated correctly or if the tree decides there is too much fruit and drops some. This never happens in June but earlier, about April in our climate. It is said to "Thin after June drop." I have not seen this to be the case. I would suggest in our hot and variable desert climate to thin early and thin according to the variety you have. Ignore June drop. If you have lots of flowers, lots of fruit, then thin!

Fruit to Thin, Not to Thin, and Minor Fruit

Fruit and relatives of these fruit to thin include peach, nectarine, apricot, plum, pluots, apples, European pears, Asian pears. I have not seen any value to thinning pomegranate, fig, cherry, citrus, or jujube. But minor fruit you should consider thinning include persimmon and quince.

Grape Thinning

Grapes are thinned to make the remaining berries larger (desert grapes) or intensify the flavor (wine grapes). Thinning is done in three ways: spacing of bunches. reducing the size of bunches (pinching), and removing small bunches. Thinning is done when the berries are the size of baby peas.