Why Practice Apple Tree Thinning?
I love apples. It is good food and good medicine. When I first started growing my own apples, I resisted the notion of thinning my apples. I looked at that abundance of tiny, tantalizing apple babies in early summer and put my pruning shears back in the tool shed. I saw the tree was experiencing “June Drop” already. Why stand in the way of what Mother Nature is already doing? As with anything else in my life, I had to learn the hard way. Apple tree thinning is preventative medicine for my trees.
Apple trees, left unthinned will exhibit a few behaviors that run contrary to the apple grower’s interest. It may seem counter intuitive but taking out apples actually offers a more abundant harvest. In my home climate here in the temperate north, apple trees bloom in early spring. Native pollinators like mason bees emerge from their winter dormancy to harvest the nectar and spread the pollen throughout the tree blossoms. Even with this spectacular attention, only 5-10 percent of all blossoms will develop into fruit. That’s not a bad thing. Healthy apples need nourishment from the tree itself. This low number of pollinated flowers results in “birth control” which results in a healthier tree in the long run.
By June, apple fruit is starting to form and the tree will prioritize what growers call the “King’s fruit.” This is the apple in the center of the cluster that is the tree’s self selected primary fruit of the group which normally gets most of the water and nutrients. Orchardists will prune off the other apple buds to give priority to this fruit.
In June, you will notice that many of the apple buds surrounding the “King’s fruit” will have reddish stems. These will drop off the tree on their own during “June Drop.” In southern climates, this will happen earlier in the year. Even with this natural selection, trees need help. Apple trees are hybrids. Humans have nurtured them into a highly productive state and need extra help from thinning to remain healthy.
Left to it’s own devices, apple trees will alternate their production years. One year, it will grow an abundance of apples, more than the orchardist can preserve. The next year, it will grow a pittance of apples, leaving the orchardist in the lurch for food. Thinning allows the tree to produce apples at a steady pace without apple waste or famine.
Summer pruning of branches is only for wood that is diseased, infested or injured. Any significant pruning or tree shaping should be reserved for the time of year when the tree is dormant. It should have dropped its leaves and have no signs of new growth yet.
Thinning Advantages
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Summer inspection of the tree for insect, disease, or physical damage
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Larger, healthier fruit to harvest
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Decrease weight to tree branches to minimize breakage
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Decrease needed water or fertilizer to tree by eliminating unproductive fruit
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Decreased need for pest or disease control by manually thinning fruit that is a home to coddling moths or other insects
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Increase sun exposure to fruit for more flavonoid production
Equipment needed
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Sharp pruning shears
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Rubbing alcohol and gauze/cotton rag
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Bucket for rejected fruitlets
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Tarp
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Ladder
Procedure
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Spread tarp under tree.
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Put bucket in the center of the tarp.
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Select a branch to inspect and start with the cluster at the tip of the branch.
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Locate “King’s Fruit” in target fruitlet cluster.
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Inspect the fruitlet clusters for diseased or damaged fruit.
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If the “King’s Fruit” at the center of the cluster is damaged, infested or diseased, select the 2nd largest fruit as the one to preserve from the cluster.
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Either snip rejected fruitlets from cluster with pruning shears or twist fruitlet to break it from the cluster taking care not to damage the spur, leaves or branch.
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Prune off clusters less than 6 inches apart from each other.
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Throw fruit into bucket to be composted or buried.
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Remove any damaged branches with pruning shears at the base of the branch and wipe shears with the gauze/rag soaked in rubbing alcohol between branches to prevent diseases from spreading.
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Throw damaged branches onto tarp for proper disposal.
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Work into the tree being certain that your ladder is stable at all times.
