How to Fertilize Blueberries: A Complete Guide for Home Gardeners

Blueberries are a rewarding fruit to grow at home — they’re delicious, packed with antioxidants, and attractive in the garden. But to produce a healthy crop year after year, blueberry plants need the right nutrients at the right time.

Fertilizing correctly is essential to encourage growth, improve berry production, and maintain overall plant health.

This guide covers when and how to fertilize blueberries, what types of fertilizer to use, and tips for maximizing your results.

Why Fertilization Matters for Blueberries

Blueberries are unique compared to many other fruiting plants. They:

Prefer acidic soil with a pH between 4.5 and 5.5
Have shallow roots that are sensitive to over-fertilization
Need a steady supply of nutrients, especially nitrogen, to support fruit production

Providing the right fertilizer at the right time helps promote strong root development, lush foliage, and abundant, flavorful berries.

When to Fertilize Blueberries

The fertilization schedule for blueberries varies slightly by climate, but these general guidelines apply to most home gardens:

Early spring: Apply the first round of fertilizer when buds begin to swell, typically in March or April.
Late spring: Apply a second round 4 to 6 weeks later, usually in May or early June.
Avoid late-season fertilizing: Stop fertilizing by early July to prevent new growth that could be damaged by fall frosts.

Newly planted bushes may require less fertilizer in their first year. For mature plants, annual fertilization is key to keeping them productive.

Best Fertilizers for Blueberries

Blueberries thrive with acid-forming, slow-release fertilizers. Here are the most common and effective options:

1. Ammonium sulfate

A good nitrogen source that also helps maintain soil acidity
Apply with caution to avoid burning roots

2. Urea (acid-forming types)

Provides nitrogen and encourages growth
Look for coated or slow-release versions to reduce burn risk

3. Fertilizers labeled for acid-loving plants

Products like Holly-tone or Azalea, Rhododendron, and Camellia fertilizers are excellent choices
Balanced formulas often include beneficial micronutrients

4. Organic options

Cottonseed meal, blood meal, fish emulsion, and composted manure can also work well
These improve soil structure and release nutrients slowly

Avoid fertilizers with nitrates, as they can damage blueberry roots. Always check the label to confirm compatibility with acid-loving plants.

How to Apply Fertilizer

Proper application ensures nutrients reach the roots without harming the plant:

Measure carefully: For mature bushes, apply 1 to 1.5 ounces of actual nitrogen per year, split into two applications.
Apply around the drip line: Scatter fertilizer evenly in a circle beneath the outer edges of the plant’s canopy — not directly at the base.
Water thoroughly: After applying fertilizer, water well to help nutrients reach the roots.
Mulch afterward: A 2- to 4-inch layer of pine bark, sawdust, or pine needles helps conserve moisture and maintain soil acidity.

Signs Your Blueberries Need Fertilizer

Watch for these indicators that your plants may need a nutrient boost:

Slow or stunted growth
Pale green or yellow leaves
Poor fruit set or small berries
Red leaf edges (often a sign of phosphorus deficiency)

However, avoid over-fertilizing, which can cause excessive leaf growth at the expense of fruit, or even damage the plant’s shallow root system.

Final Thoughts

Fertilizing blueberries correctly is key to growing vibrant, fruit-bearing bushes. By choosing the right product, applying it at the right time, and keeping your soil acidic, you’ll help your blueberry plants thrive season after season.