Best Mulching Practices for Blueberries

In blueberry production, mulches create an optimum environment for root growth and help control weeds. But not all mulches are created equal.

Wherever blueberries are grown commercially, sawdust is the mulch of choice. It is great at weed control but also means more fertilizers must be applied because nitrogen doesn’t always get through to the roots.

Mix in rising prices for softwood sawdust and fertilizer, and searching for alternatives becomes appealing.

The BC Blueberry Council, in partnership with the University of British Columbia and Agriculture and Agri-Food Canada, recently completed a study to measure the effects of a variety of mulches on nutrient availability, soil moisture and temperature, and overall crop health.

Over a period of three years, field experiments were conducted on a range of soil types and the results were analyzed.

At the outset, yard trimmings compost seemed very promising because it contains organic forms of nitrogren. Over the longer term, however, it was actually found to suppress plant growth and result in more weeds when used alone.

While sawdust mulch remains the best management practice overall for blueberry production, the researchers did conclude that layering yard waste compost over an existing layer of sawdust should allow growers to get by with less fertilizer. These results were shared with growers who will, no doubt, continue to investigate cost-saving alternatives.

Funding: $60,000 through former federal adaptation programming. (A0576)