Mulch for Blueberry Plants

Soil pH

• Blueberries grow in acidic soil with a pH below 5.5. Acidic soil has a low pH while alkaline soil has a high pH. Blueberries grow best when the soil pH levels fall between 4.5 and 5.0. Amend soil before planting blueberries to bring the pH levels into a suitable range. University extension services often provide soil testing. The mulch layer can help keep soil acidic if the area already falls within an acceptable range.

Benefits of Mulching

• A thick layer of mulch spread under blueberry shrubs suppresses weeds by smothering weed seeds before they get established. The organic material insulates the soil regulating the temperature around the roots during hot summer weather and cold winter weather. Moisture in the soil evaporates less quickly under a layer of mulch. Mulching requires a little extra effort each spring, but you save time later when the weeds pop up and the soil starts to dry out in summer.

Mulches for Blueberries

• Blueberries do not require specifically acidic building mulch material, but if your soil already falls on the alkaline side, it helps. Acidic mulch materials include chipped bark or sawdust from softwood trees like pine, redwood and fir, acidic compost, pine needles and peat moss. Nonacidic building mulch materials are suitable when the soil is already acidic. Sawdust, leaf mold, hardwood bark, chipped wood, straw, manure, shredded coconut husks and coco hulls make good mulch material.

How to Mulch Blueberries

• In the first year after planting, mulch blueberries with a 3-inch layer of material. Use an acid-building mulch like pine needles or sawdust from fir or pine trees and extend it out in a circle 2 feet in diameter. Hold the mulch back two to three inches from the base of the trunk. In the second year and beyond, spread a 6- to 8-inch layer of mulch in a circle that extends from the base of the trunk to the area under the outermost branches.