Mad About Berries

How To Fertilize Blueberries?

Blueberries, often dubbed "nature's candy," are not just delicious but also packed with nutritional benefits. Cultivating these delightful berries in one's backyard can be both a rewarding and therapeutic experience.

Understanding the nuances of blueberry farming can lead to bountiful harvests season after season. Fertilizing blueberries correctly is essential to maintain healthy plants and encourage bountiful fruit production.

Published: September 14, 2023.

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Growing Blueberries: A Garden's Sweet Reward

Blueberries, with their sweet-tart flavor and deep hues ranging from blue to purple, have long been a favorite among fruit enthusiasts.

These delightful berries, which are as delicious as they are nutritious, are often regarded as a superfood, brimming with antioxidants and vitamin C.

But beyond their nutritional accolades, there's another compelling reason to embrace them: they can thrive in home gardens, allowing enthusiasts to enjoy the gratification of harvesting fresh, home-grown fruit.

While the idea of cultivating blueberries might seem daunting to the uninitiated, with a little bit of knowledge and preparation, it becomes a journey filled with learning and joy.

Each variety of blueberry plant, from the towering highbush to the more diminutive lowbush, has its own unique charm and set of requirements. A successful blueberry garden begins with understanding these needs and ensuring the right environment for these berry-producing plants.

Location is key. Blueberries thrive in well-draining soil that is acidic in nature, with a pH level ideally between 4.5 to 5.5.

While they love the sun, ensuring they receive adequate water without getting waterlogged is equally crucial. The balance of these elements, coupled with regular care, ensures that the blueberry plants yield a bountiful harvest.

When fertilizing the blueberries, it is very important to provide the required nutrients and to keep the soil acidic.

However, note that blueberries come from areas with soils that are low in nutrients but are acidic (this "acidic" must be emphasized!). If the soil is too alkaline, or in rare cases, too acidic, blueberries won't be able to absorb the nutrients.

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How To Acidify Soil For Blueberries?

There are several methods to acidify soil, not only for blueberries but also for other plants that require acidic soil:

Elemental Sulfur

Adding elemental sulfur is one of the most common methods to acidify soil.

  • For sandy soil: Apply 1 pound of elemental sulfur per 100 square feet to decrease the pH by one unit (e.g., from 6.0 to 5.0).
  • For loamy soil: Apply 1.5 to 2 pounds per 100 square feet.
  • For clay soil: Apply 2 to 3 pounds per 100 square feet.

For short, that would mean one smaller cup of sulfur per plant every 1-3 years, depending on the local soil conditions.

Note: It takes several months for sulfur to affect soil pH, so it's best applied in the fall for the upcoming growing season. Also, when applying acidifiers and fertilizers, always read the instructions and act accordingly.

Ammonium Sulfate

Ammonium sulfate is frequently suggested as the go-to fertilizer for blueberries, given its efficacy in keeping the soil's pH level acidic.

The amount you should apply initially largely depends on your soil's existing acidity level.

Generally, an annual application of 2 to 4 ounces per bush is sufficient to sustain a pH range of 4.5 to 5.0.

However, ammonium sulfate is very simple to over-apply, and as it's a synthetic commercial fertilizer, it isn't permitted in organic farming.

Select the Right Fertilizer

Fertilizers formulated for acid-loving plants, such as those for azaleas, camellias, and rhododendrons, are probably the best option since they refeed the plants and help keep the soil acidic.

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Options include:

  • Granular fertilizers: These are slow-release and can be applied at the base of the plant.
  • Liquid fertilizers: These provide quick nutrients but may need to be applied more frequently.

Blueberries have a shallow root system, so be very careful when applying fertilizers or doing any task that involves working the soil around them.

When to Fertilize

When to fertilize is also important since not all blueberries are the same, and they are not grown in the same conditions.

  • Newly planted blueberries: Blueberries are planted in organic-rich acidic soil and can be fertilized right away with a small amount of slow-release fertilizer, or they can be lightly fertilized 1 month after planting.
  • Established plants: Fertilize once in early spring and again in late spring. If using a slow-release formula, you might only need to fertilize once.
  • Plants grown in containers: Fertilize more often using smaller amounts of slow-releasing fertilizer.

How to Apply

The recommended amount (as per the package) of granular fertilizers should be sprinkled around the base of the blueberry bush, avoiding direct contact with the trunk. Extend it out to the drip line (the outermost circumference of the plant canopy).

Liquid fertilizers should be mixed with water as directed and applied around the base of the plants.

Watering After Application

Water the plants after applying fertilizer to help the nutrients seep into the soil and reach the roots. This also prevents potential root burn.


Mulching with pine bark, pine needles, or sawdust can help maintain soil acidity and moisture, which benefits blueberry plants.

wooden mulch

Apply a 2-4 inch layer around the base of the plant, keeping the mulch a few inches away from the stem to prevent rot.

Soil pH Monitoring

Regularly test the soil pH to ensure it remains in the ideal range (4.5 to 5.5).

If the pH is too high, consider adding soil acidifiers like elemental sulfur. If it's too low, which is rare, lime can be added to raise it. Always adjust pH outside of the plant's active growing season and make changes gradually.

Again, probably the best option is to use fertilizers intended for blueberries and other plants that prefer acidic soil - such fertilizers contain all required nutrients, but also help keep the soil acidic.

blueberry harvest

Avoid Over-fertilization

Excess fertilizer can damage blueberry plants and reduce yields. It's essential to follow the recommended application rates and observe the health and growth of your plants.

Lastly, local conditions and the specific variety of blueberries can influence fertilization needs. Consider consulting local garden centers or nurseries for region-specific advice.

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