Jul 192010
Curious to know if lasagna gardening worked, I tried a series of experiements with fabulous results.

These blackfoot daisies and verbena are growing in The Labyrinth Garden, which I have grown entirely through Lasagna Gardening methods.

Lasagna Gardening is essentially a method of gardening in a huge compost pile, but with no turning!  Many people are attracted to this layered, no-dig, no-till method because it uses organic materials while promising a huge reduction in labor.  The method was created by Pat Lanza.  I highly recommend that you read her books for a full description of the method before creating a Lasagna Garden, but I’ll give the basics of the method here. 

Brief Description of Lasagna Gardening

You can use this method for garden beds of all sizes, including very large or very small.  Cover the area with a thick layer of wet, overlapping newspapers to suppress existing weeds. 

Next, build the bed by laying down organic materials in 4-inch layers. (The method does not require alternating carbon and nitrogen layers like a compost pile, but a variety of materials is beneficial.)

Put the bulkier materials down first to form the bottom layers, then chopped or finer materials towards the top.  End with a layer of compost or soil.

Materials will decompose in place. 

If the bed you have created is high in nitrogen, wait until the temperature drops before planting.  Otherwise, you can install transplants right away. 

Plant transplants directly in the bed of decomposing matter; seeds can be planted in the top layer of soil or compost.  Over time, continue adding organic materials on top as mulch to replenish the bed.


Lasagna Gardening grew these ranunculus

These are ranunculus amongst iris leaves. The beds had not yet filled out with plants around them, so it's easy to see that they are planted in chopped leaves and grass clippings, not soil (i.e., Lasagna Gardening).

There’s No Way This Can Work . . . Is There?

When I first heard of Lasagna Gardening, I really had my doubts that this method would work.  After all, if people could just throw organic wastes in a bed to create a garden, why were we building, watering and turning compost piles (not to mention carting organic wastes and finished compost to and from the garden)? 

On the other hand, if it did work, I wanted people to know about it.  There was only one way to find out — try it for myself!  I conducted a number of experiments.

Results of My Experiments

I set up all kinds of tests. 

There were tests on beds with edging, and beds without edging, to see if the edging made a difference.  There were beds made to heat vs. beds made that would not heat. There were beds made of relatively inert materials like compost and peat moss vs. beds made of items that would undergo huge volume reduction such as leaves and grass clippings.  There were beds that were planted the same day that they were made vs. beds that were “cooked” for 6 weeks according to Ms. Lanza’s instructions.  There were beds with seeds vs. the same bed with transplants. There were deep beds and shallow beds and skinny beds and wide beds.

My general conclusion was that Lasagna Gardening works!  I have used it ever since.

There were specific discoveries I took away from my experiments:

The method works best with vegetables and other annuals rather than permanent plantings. 

In deep beds, roots at the bottom do become compacted but it doesn’t seem to negatively affect the robustness or growth of the plants.

It is best to let the bed cure for 6 weeks before you plant.  After building the bed, water and cover it with black plastic and let it sit.  After at least 6 weeks, remove the plastic and water again.  It is ready to plant.

If planting the same day the bed is built, hot beds work best (i.e., build the bed with watered nitrogen and carbon layers to a high of at least 2 feet).  If building hot beds, make sure the root ball doesn’t reach to the hot spot in the middle so that roots don’t get over 120 degrees F.

Build the bed in layers. 

If you don’t have enough of one material to make a 4” layer, make a 1” layer or whatever depth you can, but try to make it a uniform depth across the bed.  The reason for this is that if the materials are not consistent across the bed, they will decompose at different rates so that one section may be significantly lower than another.  This situation creates problems for plants trying to survive this settling such as fissures several inches wide and roots being torn out of the soil in the uneven sections of materials.

Mary Tynes, Master Composter, www.mastercomposter.com


Compost Basics

Compost Ingredients

Compost Piles

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