I heard someone on public radio talking about “lasagna” gardening? Does that really work and would it be possible to try it this spring (assuming the snow melts?) — Terry, Caledonia.
“Lasagna Gardening” is the name of a book written by Patricia Lanza, who has also written “Lasagna Gardening with Herbs” and “Lasagna Gardening in Small Spaces.” The technique is not new, and if done correctly, works well to create a new garden area using composted materials. Another name for this garden creation technique is “sheet composting,” which may give you a better idea of what is at work. It is basically layering newspaper and organic matter on top of existing turfgrass to create a new garden space.
The idea of composting in layers to create a garden is interesting, and potentially easy. I say potentially easy because it could be disastrous if not done correctly. The organic material added to create the garden needs to be chipped, and you must use the right combination of “browns” and “greens” in your layers, just like in a compost pile.
The risk in doing a layered garden area is in the time and conditions. If the conditions are not right and the layers are too wet or too dry, or too green or too brown, the degradation will not occur properly. When the time comes to plant your garden you will find, not rich, hummus-like compost, but layers of slime or the opposite, dry material unchanged in composition. Decomposition takes time, the longer your lasagna layers have to work, the better the garden will be.
Previously I have talked about creating a garden by laying down 12 to 15 layers of newspaper topped with four or more inches of good quality compost. This technique done in the fall will result in a great, easy to dig garden by spring. The newspaper provides enough of a barrier to kill the grass beneath, and there is no need to till, because you are planting in the compost. The plant roots will take care of finding the native soil under the paper.
In lasagna gardening, Ms. Lanza recommends three layers of wet newspaper, topped with alternating layers of grass clippings, chipped leaves, seed free chipped weeds, food waste, pine needles, spent flower blossoms, other yard waste, manure, compost, and peat moss.
UW-Extension recommendations would not include any manure there for at least one full year before using the area for a garden. Manure of any kind must be fully composted before applying to the garden; the potential dangers associated with manure today are too great to take a risk in applying non-composted fecal matter to a food production garden.
Leaving out the manure gives the potential for a planting site in the next year, if the conditions are right for the decomposition to take place. If the “lasagna” can be dug, you can plant. If the organic matter is not decomposed however, you may end up with some nitrogen deficiencies in your plants as the organic matter underneath keeps degrading and competing for nutrients.
Trying to do lasagna-style garden preparation in a single season, that is starting the layers in spring and planting in spring, is not going to work very well unless all organic matter on top of the newspaper is fully composted.
To learn more about starting a garden, visit our UW-Extension Horticulture website at http://hort.uwex.edu or our People+Plants community garden site at http://fyi.uwex.edu//peopleplants.
Master gardener volunteers serving as plant health advisers are able to answer your questions at firstname.lastname@example.org or by calling the Horticulture Helpline at (262) 886-8451 (Ives Grove) or (262) 767-2919 (Burlington).
Dr. Patti Nagai is the horticulture educator for Racine County UW-Extension. Submit your questions for The Journal Times Q&A column to Dr. Nagai at Patti.Nagai@goracine.org and put “Question for RJT” in the subject line.