When to fertilize blueberries

The best time to fertilize established blueberry bushes is in early spring or early fall. New blueberry bushes can be planted in pre-fertilized soil or fertilized about a month after planting.

When to fertilize blueberries

Blueberry plants benefit from a fertilizer application in early spring or in early fall. Either fertilize blueberries first thing in the spring as the blossom buds begin to form, or wait until the leaves start to drop in the fall. Avoid fertilizing blueberry plants after the blossoms have opened, while the berries are growing, or during the heat of summer.

“Apply a fertilizer formulated for acid-loving plants each spring, before buds begin to open, following the package directions. Make sure not to use concentrated fertilizer or overfertilize as blueberry roots are close to the surface and can be burned.”

Growing Berries and Fruit Trees in the Pacific Northwest: How to Grow Abundant, Organic Fruit in Your Backyard, by Tara Austen Weaver

Blueberry plants generally require feeding only one time per year. A proper soil test can help determine whether fertilizer is actually required. You may find they don’t need any fertilizer at all (and might in fact result in bitter berries if over-fertilized). When in doubt, don’t feed the plants with unnecessary fertilizer, or choose a gentle nutrient-containing organic mulch like homemade compost.

“Relative to most perennial fruit crops, they have low nutrient needs and are sensitive to excessive nutrient levels in the soil.”

Managing Blueberry Nutrition, by Eric Hanson, Department of Horticulture, Michigan State University

What to fertilize blueberries with

Blueberries grow well with an annual 1″-thick application of homemade compost as an organic mulch. Soil pH correctors such as sulfur are sometimes added just prior to mulch placement.

Nutrient-deficient plants can be fertilized with a gentle, non-burning, high-quality organic fertilizer formulated for plants that grow in acidic soil. Only use formulated fertilizer products if your berry bushes are nutrient-deficient!

Here are some blueberry plant fertilizers to consider:

• Dr. Earth Organic Fertilizer for Acid-Loving Plants (3-4-3)
• Espoma Organic Berry-Tone Fertilizer (4-3-4)
• Down-To-Earth All-Natural Soybean Meal (7-1-2)

“Fertilize lightly with a formulation suitable for acid-loving plants – I use soybean meal at the rate of about 1 pound per hundred square feet, which I apply, along with the mulch and, if needed, sulfur, in autumn after leaves fall. Applied in autumn, the mulch also smothers certain disease spores that might infect plants in the spring.”

Landscaping With Fruit: A Homeowner’s Guide, by Lee Reich

Fertilizing new blueberry bushes

New blueberry bushes can be planted in pre-fertilized soil, or they can be fertilized about a month after planting. Pre-fertilizing the soil enriches the ground around the root ball and encourages it to grow out into the surrounding soil. You can also wait for the bush to get established for a few weeks and then apply a high-quality, gentle fertilizer.

“Soil care for blueberries begins before you even plant them. Check the soil acidity (pH) and mix a generous bucketful of peat moss with the soil of each planting hole. If the pH is not in the blueberry-friendly range of 4.0 to 5.0, add sulfur (a mined, natural mineral).”

Landscaping With Fruit: A Homeowner’s Guide, by Lee Reich

“Blueberries can be fertilized about a month after planting, using a fertilizer formulated for azaleas, rhododendrons, and other acid-loving plants (follow recommended application instructions). Make sure to apply any fertilizer evenly, out to the drip line of the plant (the perimeter of the branches and leaves), and water in well.”

Growing Berries and Fruit Trees in the Pacific Northwest: How to Grow Abundant, Organic Fruit in Your Backyard, by Tara Austen Weaver