Tips for Growing Blueberries in Illinois

By Carol Bale

Anthony Bratsch, Extension Educator, Horticulture, with the University of Illinois Extension in the Effingham Center, thoroughly supports the idea of testing soil pH and preparing the garden soil one year in advance of planting the blueberries. “Illinois soils tend to be heavier than those in southwest Michigan and often need amending to improve drainage and also lower pH. The higher percentage of clay in our soils makes them slower to drain, and the addition of organic matter can improve internal drainage and enhance root development. In addition, organic materials such as peat moss help to lower pH because of its natural acidity.”

“Attempting to change soil pH in heavier soils can take longer because of their greater “buffering” capacity, which means there are more soil particles to chemically change. We recommend using elemental sulphur to lower soil pH and not aluminum sulphate, which can be toxic to plants at the high levels needed to initially drop soil pH. It is important for gardeners to work in soil amendments with a rototiller to improve soil particle contact with the sulphur, and thus more effectively lower pH. Using ammonium sulphate fertilizer (not to be confused with aluminum sulphate) to fertilize your blueberry bushes will keep pH levels low over time.”

“Lastly, Illinois gardeners may want to consider growing blueberries in raised beds that are 4-6 inches above the normal soil line, to help improve drainage,” explains Bratsch.

More Growing Tips

Amend soil to required pH levels and add organic matter. Plant one or more of 2-3 different varieties of blueberries.

Allow 3 feet between each plant and 3 feet between each row.

A starter fertilizer can be used at planting time and then acidic fertilizer can be applied after flowering. Fertilization should cease by July 4.

Shrubs need an inch of water a week and up to 2 inches a week if the weather is very hot and dry. Continue to water in August-September as the plants are setting fruit buds for the next season. Plants should be mulched with 3-4 inches of mulch.

Unless you are purchasing a 3-year-old plant, which will be larger and more costly, most plants purchased in garden centers are 1-2 years old and will not produce a crop until year three.

Remove the shrub’s flowers for the first two years. This means forfeiting the berries during those years but results in a larger plant, and it will produce more and larger berries from then on.

Prune in early spring. Remove the largest canes at the bottom of the plant and prune out spindly and broken canes. Check to be sure the middle of the shrub is receiving sunlight. If the shrub is too dense, prune a few canes at the bottom and remove.

Use bird netting during harvest. (This can be removed after harvest.)

Watch for rabbit and deer damage in the winter and apply animal repellents as needed.