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People of particular climates are expressing exacerbated problems with their lasagna gardens and throwing the term sheet mulching in the bucket too. Sheet mulching is not wisely used in the same scenarios as lasagna gardening, so the issues are irrelevant in the right setting.
This article is to draw a line between the two strategies so we can have a clear outlook when choosing an approach to persistent weed problems.
The foundation of the line is based on the definition of ‘mulch.’ Mulch is a medium applied to the surface of the soil (not beneath it!)
So it’s safe to say: lasagna gardening is not synonymous with sheet mulching.
What is the difference between sheet mulching and lasagna gardening?
Sheet mulching is a foundational element of primarily perennial landscapes and some alternative methods work well for vegetable gardening too. Too often, I see ‘lasagna gardening’ used interchangeably as if it’s the same action as sheet mulching. The blanketing of problems as if it applies to all scenarios can easily deter people from well functioning sheet mulch.
Lasagna gardens bury sheets of material under a mound of plantable soil or medium. Sheet mulching is a complete light-blocking mulch for plants grown in the ground to establish without competition. Lasagna gardens often receive a yearly layer of sheets and soil. Sheet mulch only has mulch on top.
It’s important to understand the difference so you can assess your needs and make decisions based on relevant stories.
Sheet mulch is not “several layers of different mulches or composts.” This description begins to refer to lasagna gardening. If sheets are laid yearly, or on the ground and buried with fresh soil, it creates a lasagna garden (or can be referred to as sheet composting). Sheet mulching is a one-time laid weed-smothering mulch on top of growable mediums for in-ground planting. Often sheet mulch is buried under fresh mulch.
People began lasagna gardening—year after year—so they could enjoy the ease of a fresh slate. Unwanted plants can overtake a space with a year of growth—so the idea is to lay sheets every year under a fresh import of soil or another medium to grow annual crops. The sheets compost beneath the surface and soil is built year after year—a good way for sustaining the nutrient-heavy demands of vegetables.
The cons? Imported material is an inherently unsustainable garden practice and is often applied to situations where pest problems are relevant. Pests such as:
- cabbage worms
These pests have been complained about primarily in colder climates. In the table below, solutions to these issues are addressed.
Weeds grow rampant in a vegetable garden because the act of growing non-permanent plants is the act of repressing natural maturity. Disturbance encourages repair (a weed’s intention).
If you’re after a weed-free vegetable garden and don’t want to make (or endure the problems of) a lasagna—try method #6 “the no-tillers way” of sheet mulching.
Organic mulches are often applied at the end of a growing season to protect the soil and fresh added compost. The problem for people with a short growing season is a delayed start when growing vegetables. When the soil is covered by natural material it takes longer to warm. So I suggest the inorganic approach linked above.
For permanent perennial planting such as a food forest; sheet mulching once is sufficient to keep weeds at bay because permanent plantings are progressive (without disturbance).
Slow-to-warm spring soil isn’t a problem for perennials since the act of planting is already done.
You’d lay sheet mulch and top it with fresh mulch like wood chips. As the sheet mulch material breaks down beneath, the woodchips will prevent plants from growing through or returning to life. All perennials previously planted will establish happily without competition.
You can also lay sheet mulch to make a mushroom bed!
How to prevent sheet mulch or sheet composting problems
Annual. . . or perennial . . . With the appropriate sheet-mulch method you can still reap the benefits of problem-free weed freedom.
Even though the same problems can be caused by sheet mulching in certain circumstances it’s most important to understand that a remedy exists. Various situations demand different methods of sheet mulching.
Here is a simple guide of when and when not to use sheet mulching or lasagna gardening:
|Lasagna gardening||annual crops in cold climates lacking snakes and reptiles||voles/rodents, slugs, cabbage worms||inorganic temporary tarp sheet mulch, row covers for brassicas|
|Semi-permanent tarp sheet mulch||anywhere in the world||wasteful of resources, lack of soil-building||inorganic temporary tarp mulch, any organic sheet mulching or lasagna gardening|
|Organic sheet mulching with mulch on top||annual crops in cold climates||cold spring = late start, voles/rodents, slugs||inorganic temporary tarp or semi-permanent tarp “mulch”|
|Organic sheet mulching with mulch on top||Perennial plantings||Voles/rodents, slugs||introduce reptiles & snakes: build elements of habitat for them|
|Organic sheet mulch with manure layer with mulch on top||Perennial plantings||burnt plant roots||use aged manure or green manure|
|Organic sheet mulch alone with no mulch on top||Perennial plantings/vegetable garden pathways||hydrophobia of sheets could lead to underwatered plants||apply regular mulch on top|
This article was originally published on foodforestliving.com. If it is now published on any other site, it was done without permission from the copyright owner.
The methods listed in the table are described here.
For vegetables, our favourite sheet mulch is the inorganic temporary tarp method. In between tarping we grow food or grow regenerative cover crops. The tarp is only applied for a sufficient time to kill the previous crops, covers, flowers, and weeds that grew.
For perennial plants, we use organic sheet mulch with mulch on top.
We allow weeds to grow around new trees until we have the material to fence them from the deer. Once we have fence material—within one year of initial planting—we chop the overgrown weeds, smother them with leaf bag sheet mulch, and top it with wood chips. Carefully, we ensure our plants roots still have access to oxygen for healthy growth.
Related post: (coming soon) How to properly mulch a fruit tree
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