If you want healthy, productive apple trees, they need full sun. Full sun means exposure to a minimum of six hours per day of direct summer sunlight.
Do you want to plant apple trees in a location where you’re concerned there might not be enough sun?
It can be tempting, but trees that receive less than six hours of sun per day can develop thin, weak limbs and grow inadequate leaves and fruit.
If you want your apple trees to flourish, there are a few things you can do to ensure they do not get too little or too much sun exposure. We will explore:
- Where to Plant Apple Trees for Optimal Sun
- Spacing Between Trees
- Effects of too Much Sun
- Pruning and Training to Optimize Sun Distribution
There is a lot to factor into plant placement such as soil quality, drainage, harsh winds, sewer lines, etc., but sun requirements are the first priority.
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1. What is the Best Placement for Proper Sun Exposure?
The best placement for planting apple trees in order to receive proper sun exposure depends on your climate.
Hot & Dry
In areas where summer is especially hot and dry, the National Gardening Association recommends avoiding slopes facing south or southwest.
The intense sun requires additional watering and can cause sunburn. Planting on slopes facing east or west can mitigate the effects of harsh summers.
Cool & Cloudy
In cloudy regions, apple trees grow best on the south side. If you plant on the northern or eastern side of a slope or wall it can hinder growth.
According to Cloud Mountain Farm Center, if shade covers your apple tree before 4pm at the height of summer, the tree is likely receiving too little sun to produce quality fruit.
2. How Far Apart Should You Plant Apple Trees?
It is important to plant apple trees far enough away from other trees for full sun exposure, especially trees with large, spreading canopies.
If you are planting several apple trees, the Arbor Day Foundation offers spacing guidelines. Standard apple trees need 35’ of space while dwarf trees need 10’ and semi-dwarfs 12’.
However, if you are in a particularly cold climate with shorter growing seasons, you do not need quite as much space between trees. The University of Maine recommends 6-8’ for dwarf trees and 25’ for standard trees.
3. Can an Apple Tree Get Too Much Sun?
Apple trees need full sun, but too much sun under hot conditions causes sunburn; too much sun under freezing conditions causes sunscald.
Both sunburn and sunscald damage tree tissue and require the same treatment.
Young tree trunks are susceptible to sunburn, especially at the base of the trunk near the soil line where sun hits directly and reflects off the ground.
Signs of a sunburned trunk includes reddish brown discoloration and slight recession at the burn site. A severe burn can hinder growth or kill the tree.
More mature trees can also experience sunburn when they are pruned during summer exposing the inner branches and trunk tissue to increased sun radiation.
The apples themselves can burn as well.
Apples located on the southwest side of a tree are at greater risk of sunburn because they receive the most direct sunlight.
Sunburn can occur during stretches of hot and sunny weather. You can identify sunburn by the brown welts that develop at the hotspots.
According to the University of Minnesota, sunny weather combined with temperatures of over 90℉ can cause sun necrosis which is decay at the sunburn spot.
Sunscald is caused by sun exposure on cold winter days and can be an issue for young trees planted in regions with freezing winters.
The sun melts the water under the surface of the tree. Then, when direct sun is obscured by a cloud or the sun sets, the water quickly freezes causing cell tissue damage.
If your tree is planted on the south side of a building or slope, sunscald is more likely than if it’s planted on the north side.
Preventing sunburn and sunscald is easy.
Washington State University recommends painting the trunks and lower branches of young trees with white latex paint or wrapping the trees with reflective material. If you use the wrapping method during the summer, leave space for airflow and frequently check for pests.
4. Prune and Train Apple Trees to Optimize Sun Exposure
Pruning and training apple trees is designed to maximize light distribution, especially for the center of the tree where foliage is thick.
Light distribution directly affects the size, color, and sugar levels of apples.
Prune trees during dormancy in late winter or early spring when there are no leaves on branches. Summertime pruning can be helpful, but significant cuts can expose normally shaded plant tissue to sun radiation too quickly, making it vulnerable to sunburn.
Here are some pruning and training tips for optimal sunlight distribution:
- Eliminate vertical branches and those growing downwards because these block light.
- Prevent downward growth by shortening limbs higher in the canopy.
- Train (bend and tie) scaffolds to an optimal angle. PennState recommends 50°-75° from vertical.
- Thin out vigorous branches in the canopy of multiple-leader (vertical stems at the top) trees. If these are not cut, they can eventually block sunlight from the lower limbs and minimize fruit production.
- Promote pyramid-shaped trees as these distribute light well and require less pruning maintenance than multiple-leader trees.
- Remove dead, diseased, and dying branches completely. Doing so will not only prevent pests and disease but further opens up space for sunlight.
Make sure to use sharp pruners as it aids tree growth and makes cutting easier.
Fruit production requires a generous amount of sunlight, so apple trees need at least six hours a day for healthy trees and a quality harvest. Appropriate placement and spacing meets the basic level of an apple tree’s sunlight needs.
Take one step further with proper pruning and training to provide openings for maximum light distribution along the branches. The better your light distribution, the tastier and more beautiful your apples will be.
Nature Hills Nursery offers fruit trees online along with recommended zones for planting. Buy apple trees online (link to Nature Hills Nursery)