By Cindy King, CPH, The Mill of Kingstown

Growing fruit successfully in the Mid-Atlantic starts with understanding your plants’ seasonal needs. From chill hours to pruning and proper watering, this guide explains how to support fruit trees and shrubs for strong yields and fewer problems year after year.

What Are Chill Hours?

Fruit trees and shrubs rely on a natural process known as chill hours to produce fruit the following season. Chill hours refer to the cumulative number of hours during which

temperatures remain between 32°F and 45°F while the plant is dormant in winter. This period is essential for resetting the plant’s biological clock and enabling healthy flower and fruit development in spring.

If daytime temperatures reach 65°F or higher during dormancy, those warmer hours are subtracted from the chill hour total. Without meeting their minimum chill requirement, fruiting plants may produce fewer blooms, smaller fruit, or fruit that drops early or lacks flavor.

Chill Hour Requirements by Region

Fruiting varieties are typically categorized by their chill hour needs:

• High-chill plants require 900 or more chill hours and are best suited for cooler regions such as Western Maryland.
• Low-chill plants can thrive in milder parts of the state where winters are shorter or less intense.

It’s important to match the chill hour requirements of your plants to your location to ensure consistent yields year after year.

Which Plants Need Chill Hours?

All fruit-bearing trees and shrubs require some degree of winter dormancy. This includes:

• Apples
  
• Pears
• Peaches and other stone fruits
• Blueberries
• Figs
• Persimmons
• Grapes
• Raspberries and blackberries

The number of required chill hours varies by species and cultivar. Reference materials such as the University of Maryland Extension’s fruit growing guidelines provide detailed recommendations. Chill hour estimates are based on long-term climate averages and may fluctuate in warmer or drier years.

Spray Schedules and Disease Management

Fruit trees typically benefit from a late-winter application of horticultural oil, which helps smother overwintering insect eggs and scale. Additional applications of fungicides may be necessary depending on the weather, particularly during wet springs.

Monitoring your plants—especially leaves, buds, and fruit—can help you determine when to apply treatments. Always follow label instructions for both organic and conventional products. A second oil application in fall, after leaf drop, can also be beneficial.

Even if you choose not to spray, your tree will still produce fruit, but it may have blemishes or require extra cleaning before use.

Watering for Fruit Development

Water is essential during fruit formation. Plants should receive the equivalent of one inch of rain per week. During dry periods, supplement with deep watering using a hose set to a slow trickle at the tree’s drip line. This allows moisture to soak deeply into the soil where the roots can access it.

Avoid using sprinklers on fruit trees—wetting the leaves and fruit increases the risk of fungal infections.

Pruning and Tree Structure

Late winter is the ideal time to prune most fruit trees. Look for educational videos or trusted university extension services for correct pruning techniques.

Fruit trees should not be pruned into a traditional “limbed-up” shape. Instead, encourage evenly spaced scaffold branches around the trunk. This improves fruit access from the ground and promotes airflow, reducing the risk of disease.

Soil and Site Considerations

Certain fruiting plants have specific soil needs. For example, blueberries require an acidic soil pH between 4.2 and 5.0 and benefit from consistent moisture with good drainage. 

Pine needles break down too slowly to be effective in lowering soil pH. Peat moss can retain too much water and lead to root problems. Use a granular soil acidifier before planting to establish the right conditions, and test your soil regularly.

For sloped properties, plant varieties that prefer airflow—like apples or peaches—toward the top. Heat-loving crops like figs may thrive lower on the slope.

Choosing Regionally Adapted Varieties

At The Mill of Kingstown and The Mill of Salisbury, we focus on offering fruiting trees and shrubs that perform well in the Mid-Atlantic region. These selections are chosen for disease resistance, compatibility with regional chill hours, and overall growing success.

Even if a variety name is unfamiliar, you can trust it was selected with our local climate and your long-term success in mind.