Emerald Cedar Trees and Compost


We live in Scarborough, zone 5. We are trying to prepare to plant 16 emerald cedar trees (4-5 feet in height) in our backyard facing west. We have ordered some bulk ‘triple mix’ but we think that they might have sent a bag of compost instead. How can we visually tell the difference between triple mix and just compost? It was recommended that we use triple mix but can we plant the cedar trees in compost? Would be it too ‘organic’ or too rich? Your advise or help will be much appreciated.


Thank you for contacting Toronto Master Gardeners.   Planting a Tree for Life:  A Toronto Master Gardeners Guide is an excellent step-by-step guide on how best to plant your new Emerald green cedar trees (Thuja occidentalis).    The section titled “The myth of soil amendments” discusses why you should not add triple mix nor compost to the soil while planting your trees.  Just backfill around the roots with the existing soil you removed to create the holes.

Once planted, your cedars will benefit from adding a 2 to 3 inch layer of mulch around their trunks to help retain moisture and provide nutrients.  Remember to keep the mulch away from the trunk of the tree (apply like a donut, not a volcano).  Compost, wood chips or leaf litter can all be used as mulch.    Soil Fertility: A Toronto Master Gardeners Guide gives more in-depth guidance on improving your soil.  Note that compost is one of the components of triple mix, so it’s difficult to distinguish compost vs triple mix in the photo you sent along.

Additional information on cedar trees from previous questions that may be useful:

Cedar hedge planting tips

Cedar Tree Maintenance

May 9, 2023