This week I got a complimentary copy of Urban Farm, dedicated to "sustainable city living."  The cover story is Lasagna Giardino – follow this recipe for a lasagna garden that grows perfect plants – Italian or not.

This is not a new idea, but was popularized several years ago as a way of preparing soil for planting.  The article relates the steps:

1)  Prepare the ground by mowing the lawn
2)  Dig up the first 12″ of soil (double digging)
3)  Place a layer of "noodles" (paper and cardboard are popular) – the low nutrient material
4)  Place a layer of "sauce" (the green material)
5)  Repeat as often as you like and "let it cook"

I like the first step of this.  But my second step would be:
2)  Add a thick layer (12″) of arborist wood chips and "let it cook."

Double digging the soil 12″ isn't necessary: we do it because it's hard work, and we think we need to put elbow grease into the project.  Making layers of noodles and sauce isn't necessary: we do it because appeals to us -lasagna is a tasty comfort food.

There's a lot of damage that this "recipe" can cause.  Double digging the soil 12″ destroys soils structure. Don't do it. The layers of noodles and sauce (especially the sauce) can create an overload of plant nutrients. Furthermore, the "noodle" layers – the sheet mulches – impede water and air movement.  They're not needed to keep the grass from growing through. Wood chips do this just fine on their own.  And don't worry about that initial 12″ of chips.  Within a few weeks it will settle to about 8″.  Let it sit for several weeks.  Then pull aside some of the chips and take a look.  If the process is done, the grass and/or weeds will be dead and decomposing – a natural compost layer.  You can then plant whatever you like.  Reuse the chips somewhere else in your garden.

It doesn't look like lasagna, but it's a heck of a lot easier and more closely mimics a natural mulch layer than lasagna does.

Linda Chalker-Scott

Dr. Linda Chalker-Scott has a Ph.D. in Horticulture from Oregon State University and is an ISA certified arborist and an ASCA consulting arborist. She is WSU's Extension Urban Horticulturist and a Professor in the Department of Horticulture, and holds two affiliate associate professor positions at University of Washington. She conducts research in applied plant and soil sciences, publishing the results in scientific articles and university Extension fact sheets. Linda also is the award-winning author of five books: the horticultural myth-busting The Informed Gardener (2008) and The Informed Gardener Blooms Again (2010) from the University of Washington Press and Sustainable Landscapes and Gardens: Good Science – Practical Application (2009) from GFG Publishing, Inc., and How Plants Work: The Science Behind the Amazing Things Plants Do from Timber Press (2015). Her latest effort is an update of Art Kruckeberg's Gardening with Native Plants of the Pacific Northwest from UW Press (2019). In 2018 Linda was featured in a video series – The Science of Gardening – produced by The Great Courses. She also is one of the Garden Professors – a group of academic colleagues who educate and entertain through their blog and Facebook pages. Linda's contribution to gardeners was recognized in 2017 by the Association for Garden Communicators as the first recipient of their Cynthia Westcott Scientific Writing Award. "The Garden Professors" Facebook page - www.facebook.com/TheGardenProfessors "The Garden Professors" Facebook group - www.facebook.com/groups/GardenProfessors Books: http://www.sustainablelandscapesandgardens.com View all posts by Linda Chalker-Scott