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Many apple trees thin themselves naturally to some extent, so it should be no great surprise to see some aborted fruit. Often, however, the tree still holds onto a surplus of fruit which results in small, sometimes misshapen apples. To get the largest, healthiest fruit from an apple tree, you occasionally need to give Mother Nature a hand and thin apple trees. Read on to find out how to thin apple fruit.
As a home orchardist, it can be frustrating when your apple trees produce tiny, stunted fruit rather than the big, juicy apples you find at the grocery store But there are several common reasons why apple trees make small apples, and steps you can take to help your trees yield larger, tastier fruit
Common Causes of Small Apples
There are a few key factors that typically lead to stunted apple growth:
1. Insufficient Pollination
Apples require cross-pollination from a different compatible apple variety to set fruit. If flowers on your tree don’t get adequately pollinated, the resulting apples will be misshapen and undersized
Bees play a vital role in transferring pollen between apple blossoms. A lack of pollinating insects can result in poor pollination and fruit set. Harsh weather like rain, wind, or cold temperatures during flowering can also interfere with pollination.
2. Overcrowding
When apple trees are planted too close together or branches become overly congested, the increased competition for sunlight, nutrients, and water will cause stress. This leads to smaller yields of smaller apples.
3. Nutrient Deficiencies
Apples need sufficient macro- and micronutrients to support proper growth and development. Deficiencies in nitrogen, phosphorus, potassium, calcium, boron, zinc, and other minerals can all impact fruit size. Soil pH also affects nutrient availability.
4. Water Stress
Apples require adequate water throughout the growing season, especially as the fruit is enlarging. Insufficient irrigation during drought conditions or trees planted in sandy, gravely soil with poor water holding capacity often results in undersized apples.
5. Disease or Pest Damage
Diseases like apple scab and pests like codling moth larvae can damage developing apples, causing stunted growth. Prevention and control is key to minimizing their impacts.
6. Extreme Weather Events
Frost, hail, flooding, or extreme heat or cold during critical flowering and fruiting stages can also impair pollination, damage fruit, and cause apples to grow abnormally small.
7. Tree Age and Vigor
Younger apple trees often produce smaller yields of smaller apples as they become established. And older, declining trees have less energy to put into growing full-sized fruit. Maintaining optimal tree health and vigor is important.
How to Get Bigger Apples
If your apple harvest has been disappointing, don’t despair! Here are some tips to help your trees produce bigger, higher quality apples:
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Choose pollinizer trees wisely – Select compatible apple varieties that bloom at the same time as your other trees and attract ample pollinators.
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Prune annually – Remove congested branches, water sprouts, and inward facing shoots to open up the canopy and allow more light penetration.
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Thin fruit – In early summer, remove excess developing apples to leave one fruit every 6-8 inches. This reduces competition between fruits for resources.
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Control pests and disease – Apply organic pesticides and fungicides as needed to prevent insect and disease damage. Maintain good sanitation practices.
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Fertilize – Apply aged compost in early spring and supplement with organic nutrient amendments if soil test reveals any deficiencies.
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Water thoroughly – Supply 1-2 inches of water per week during dry periods to prevent moisture stress. Mulch around trees to conserve soil moisture.
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Guard against weather extremes – Protect flowers and young fruits from frost and hail with covers. Provide shade during heat waves.
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Improve soil conditions – Incorporate organic matter to improve nutrient and water holding capacities. Adjust pH if needed.
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Manage weed competition – Remove weeds and grass within the dripline that compete for water and nutrients.
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Consider dwarf rootstocks – More compact, dwarfing rootstocks can result in fewer but larger sized apples.
Reasons to Thin Apple Trees
Apple crops vary from year to year. In years of plenty, thinning out apples allows the remaining apples to grow larger and healthier. Apple tree thinning removes some of the small apples from the cluster, enabling the tree to expend its energy on the fewer remaining apples. Thinning also gives you an opportunity to inspect the tree to see if there are any diseased or broken limbs or any early signs of insect infestation that can then be effectively treated. Apple tree thinning also reduces the weight of the apple crop on the branches of the tree. This prevents potential breakage of the limbs.
The selection, timing, and method for thinning out apples is critical to the end result– the production of shapely, flavorful, and large fruit. The following apple thinning guide will instruct you on how to thin apple fruit.
How to Thin Apples
Thinning an apple tree can take place throughout the summer but, ideally, you should thin in the late spring. The tree will naturally thin itself, called the “June drop.” This doesn’t always occur in June, however. It depends on your region and the cultivar, but it does happen a few weeks after the fruit sets. It is a good time to re-inspect the tree to see if any manual thinning needs to occur. Prior to thinning the apples, take a good look at the tree to see how bountiful it is bearing this year. Fruit is borne in clusters of two to six small fruit. A large crop means that you did not thin enough the prior year. This means you should be a bit more aggressive when thinning this year. To remove the fruit from the tree, you can pluck by hand or use sterilized, sharp pruning shears or scissors. To sterilize the shears, simply wipe them down with rubbing alcohol. This will prevent any pathogens that may be on the pruners from contaminating the apple tree. Be careful not to damage the spur when you are thinning, which may decrease the successive year’s crop. If you are hand plucking, grasp the small fruit between your fingers and pull backwards so the stem snaps cleanly off. Of the two to six small fruit, thin to one large, healthy apple. First, remove those that are malformed, diseased, or insect damaged. Next, remove those apples that are smaller than the rest of the cluster. Finally, you may have to make a tough choice but it’s all for the good in the end. You may have to remove some apples that seem to be perfectly healthy, a noble sacrifice for the end goal of big, plump, juicy, and crispy fruit. Out of the two to six apples in a cluster, you want to narrow it down to one big, healthy fruit with about 6 to 8 inches (15-20 cm.) between the other apples left on the tree. This single large, healthy fruit is called the “King’s fruit.” If you have two similar looking fruit left on the cluster and just can’t decide which one to thin, remove the one which has less sun exposure. That is, the one on the underside of the leaves. Keep the apple that has the best exposure to light and air. Be methodical when thinning the apple. Begin with one branch at a time and systematically go from limb to limb. This may be a bit time consuming, but it isn’t difficult and the bonus at apple harvest time makes it all worthwhile.
What Makes Apples Misshapen or Lumpy + How To Fix It!
FAQ
How do I get my apples to grow bigger?
Sunlight: Ensure your apple tree receives plenty of sunlight (at least 6-8 hours a day). Poor light conditions can result in smaller fruit. Pruning: Regularly prune your tree to improve air circulation and sunlight penetration. This helps the tree focus its energy on producing larger fruit.
Why is my apple small?
Many apple trees thin themselves naturally to some extent, so it should be no great surprise to see some aborted fruit. Often, however, the tree still holds onto a surplus of fruit which results in small, sometimes misshapen apples.
How to increase apple fruit size?
Trials show that phosphorus can increase the commercial premium >75mm grade of apples by 24%, through increasing apple size. Thus, it is particularly important to ensure supplies are not limiting in the period 6 weeks post-flowering. Often this is best achieved by using supplementary foliar phosphate.