Since we have an abundant supply of mulch provided by the City of Abbotsford Parks Department, it is timely to discuss the use of this in your garden plot. We have a large pile located on the east side of the greenhouse.
What is it and what are its characteristics?
chipped deciduous tree/shrub branches and coniferous (evergreen) bows that have been collected from city park property or street trees during pruning or windstorm cleanup activities
coarse chips and shards of heart wood and bark (less than 1 inch (2cm)), small cones and twigs (up to 6 inches (15cm)), leaves and needles that have passed thru a green waste chipper
not tested but it is:
- very high in carbon and low in nitrogen so it will cause nitrogen deficiency in your garden soil if it is incorporated
- likely slightly acidic (pH lower than 7) so it will reduce the soil pH and cause some impact on nutrient availability
First the don’ts – please do not use the mulch for:
- weed control around the outside of your plot area. This interferes with lawn mowing and is not effective in controlling buttercup of grass
- filling in low areas in your plot or anywhere else in the garden. This just leads to soggy areas and the potential for leachate generation that may flow to others gardener’s plots
- pathways outside the garden other than in the area between the squash and herb beds
- amending your garden soil without due consideration of its impact on soil nutrition (nutrients and pH)
Then the do’s – please consider using the mulch for:
- pathways inside your own plot, but limit the depth to less than 2 inches (5 cm). Deeper layers will become saturated, generate leachate and may not be easily incorporated if another gardener takes over your plot in the future.
- light mulching around acid loving perennial plants such as blueberries. Again, a thin layer may be useful to change the moisture regime for some plats and help to suppress weeds in your garden.
- amending the soil in your plot. The mulch can be mixed into your garden (thin layer of mulch – less than 1 inch (2 cm) mixed into the top 4 inches (10 cm) but you must consider that it will impact the availability of nitrogen and lower the soil pH so this may not be beneficial to your vegetables or flowers. An application of dolomite lime and use of a nitrogen rich organic fertilizer will overcome these potential impacts.
- Cornell Gardening Resources: Mulches for Landscaping http://www.gardening.cornell.edu/factsheets/mulch/mulchland.html
- Fine Gardening Magazine: Six Tips for Effective Weed Control http://www.finegardening.com/six-tips-effective-weed-control
Prepared by: Geoff Hughes-Games, PAg, President Abbotsford Community Garden, August 2016