Thinning Your Fruit?
Thinning your fruit means selectively taking some of the fruit off the tree before it is ripe. Thinning is best done when the fruit is small. Thinning allows the remaining fruit to grow larger, reduces the breakage of overloaded limbs, reduces alternate year bearing tendencies, and can reduce the amount of wasted small fruits at the end of the season.
You can often thin your tree just before you install the Kootenay Cover. Depending on the variety of tree, the weather in the preceding winter, the vigor of the tree, how extensively you thin early in the season and other factors, you may decide to thin a second time during the growing season.
How to thin? Cut out the excess fruit with a pair of sharp scissors or hand pruning clippers. If you pull fruit off the tree, you risk damaging the fruit spur or small branches, to which the fruit is attached.
How much should you thin? Visualize the fruit as mature fruit at the size you want them to grow. Visualize how many full size fruits each limb could support. Experience teaches that over-thinning is better than under thinning. If you under-thin and a large branch snaps off, you lose all the fruit on that branch going forward. If you over-thin, the remaining fruits will just grow much larger.
Thin all the fruits that would touch the fruit you are saving. A rough rule of thumb is to remove all the fruits in a 4-6 inch radius around the fruit you are leaving. Stone fruits can be difficult to thin. The wood of peach, nectarine and apricots is more brittle than the wood on apples and pears. Thinning peaches and nectarines enough so they will not snap the branches before harvest takes every bit of resolve one can muster. You have to remember that either you thin now or snap off branches later in the season. Be brave. Be ruthless. Or hire someone else to thin your favorite tree.
What is Alternate Bearing? Many varieties of trees have a tendency to bear very heavily one year then bear very lightly the next year. If you thin the tree heavily in the heavy bearing year, you can balance out the bearing cycle to be more even each year.
How do commercial orchardists thin their fruit? Commercial orchardists typically thin with chemical sprays. We do not recommend chemical thinning sprays for the backyard orchardist. The chemicals used are expensive and powerful. When you thin by chemically spraying, you cannot tell at the time of spraying how many young fruit you are thinning. You can dramatically over-thin or under-thin as an amateur.
There are lots of websites and books that offer helpful guidance on thinning. One of my favorites is: http://homeorchard.ucdavis.edu/8047.pdf Every orchard and every tree are just a bit different when it comes to thinning details. You will learn by doing.
Remember, over-thinning is better than under-thinning.