By Penny Pawl, UC Master Gardener of Napa County
Fall and winter are great times to do sheet composting in your garden. So just what is sheet composting and what are the benefits? Some people call it smothering, sheet mulching or lasagna composting.
Sheet composting is a passive method of composting. It involves laying plain cardboard or newspaper on soil or lawn and covering it with compost or leaves or both. Autumn is the best time to do this because it gives a chance for the materials to break down and refresh the soil before spring planting.
In the spring when you are planting your garden, if the materials have not fully decomposed, you can cut through them to plant. As you water, the layered materials will continue to decompose and feed the soil.
One year, as an experiment, I planted a plant in my normal soil. Next to that I planted the same plant but used cardboard as a mulch. The soil under the cardboard stayed damper and that plant grew bigger.
Sheet composting is simple. It just takes some time to gather materials and put them to work. Before making the layers, make sure your soil is damp. Remove any large weeds but don't worry about small weeds. The composting process will smother them and they will add nutrients to the soil.
Gather a supply of clean cardboard. Some people prefer the sturdy cardboard used for large appliances, but you can use thinner cardboard, such as Amazon boxes, and double-layer it. You don't have to strip off any plastic tape. The plastic won't decompose so you can easily pick it up later. Worms and sow bugs love cardboard so it will decompose first. Be sure to overlap the cardboard so you smother what's underneath.
You can also use clean newsprint but avoid any pages with colored ink. Other good materials include dried leaves, compost from your own pile, straw and perhaps a dash of aged chicken manure. All these materials should be kept damp; if necessary, water by hand to keep the decomposition going. You may also want to cover the whole thing with plastic sheeting and add a weight so the materials don't blow away. You can layer the materials up to six inches deep.
Several years ago I demonstrated sheet composting in my garden for a garden club. I made the layers in early spring, covered the whole thing with plastic and, three months later, the decomposition was complete. Red wiggler worms and other insects and bacteria had eaten the materials and mixed them at the same time. The resulting soil was perfect.
Some people use sheet composting when they want to remove a lawn. The layered materials smother the lawn and amend the soil for future landscaping. If you are sheet composting in an area with trees or plants you want to keep, be sure to keep the layered materials away from the trunk or stem of the desired plants.
The compost committee of the Napa County Master Gardeners taped a video on backyard composting, including a demonstration of sheet composting. You can view it here:
Library talk: Napa County Master Gardeners will host a free talk on “Meditation and Wellness Gardens” on Thursday, November 4, from 7 pm to 8 pm, via Zoom. A meditation or wellness garden offers a quiet, calm place to unwind, plus other health benefits. Learn about the relationship of humans to gardens, the healing properties of gardens and some tips on creating your own wellness garden. Register here to receive the Zoom link.
Food Growing Forum: Napa CountyMaster Gardeners will present a discussion of “Cane Berries” on Sunday, November 14, from 3 p.m. to 4 p.m., via Zoom. Register here to receive the Zoom link.
Got Garden Questions? Contact our Help Desk. The team is working remotely so please submit your questions through our diagnosis form, sending any photos to mastergardeners@countyofnapa.org or leave a detailed message at 707- 253-4143. A Master Gardener will get back to you by phone or email. For more information visit http://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.
- Author: MaryJo Smith
As some of you might know, over the past 2+ years, I re-landscaped my entire yard – both front and back. It was a large project; tearing out sod and concrete, and putting in new irrigation, lighting, plantings, and hardscape. Last year, I filled in the basic landscape with edibles such as artichokes, lemons, strawberries and grapes. These additions are examples of horizontal layering — planting to give levels of color and interest. Now, I am planting out the area around my fountain to add vertical layers.
The Blue Fescue, Oat Grass, New Zealand Flax and Reed Grass were planted last year. This year, I've added larger rocks and small boulders to create some more texture, then added a few plants. Some of the plants will spread out and some of the plants will grow up. Although I want instant gratification, and everything pretty and full right now, that's not always the best way to plant (ugh, bummer). For this area, I restrained myself and put in just a few small-sized plants.
When planning/planting, it's important to think about the plant height and width at maturity, and how that will work within the space. No. 1. on the diagram to the left is the Feather Reed Grass planted last year. It has that nice shape like a fountain grass, but it's more compact and works well in narrow spaces. It will grow nice and high and full to fill in the space behind the fountain without overwhelming the area. The diagram shows the approximate height and width when the grass grows in for the season.
No. 2 on the diagram is a Day Lily. It's a nice filler for that area, provides a nice pop of color and it doesn't compete with the Reed Grass.
No. 3 on the diagram are ground covers and sedum. The ground cover is a simple summer snow. It works in full sun, is easily maintained and will produce a carpet of small white flowers. It will spread out but not up. The accompanying Sedum is a light variegated green with red rims, which will slowly spread out and provide a nice contrast against the white of the summer snow and the pale grey of the stones.
No. 4 on the diagram is a small evergreen shrub called Coleonema Pulchellum “Sunset Gold” that will grow up and out a little (2′ x 4′ at maturity). It has a nice yellow-green foliage that contrasts nicely against the silver hues in that area. It has small light pink-flowers that bloom in the spring and early summer. Also, tucked in the rocks are a couple of Gazania – just for kicks.
With the weather we experience in this area, these plants should grow/spread fairly quickly. Because none of these plants were particularly expensive, if I need to rearrange them, or take any out, there is very little financial pain.
Check back later in the summer to see how this area filled out.
In the meantime, do you have any layering you've done? Share it here. We'd love to see it.
- Author: Marime Burton
Lasagna gardening? ‘Sounds crazy even when you know what that means. Crazier still, it’s a gardening technique that really works.
A little like diets that promise you’ll lose 20 pounds a month and never feel hungry, lasagna gardening sounds improbable, exaggerated and a waste of time. Better to stick with tried and true methods that reward hard work, sacrifice and the results of long-term commitment.
So I thought, but much like those diets I can’t resist, it sounded so simple I was willing give it a try.
First of all the old garden bed does not require tilling. Just cover weeds and all with a layer of cardboard or 3-5 layers of newspaper. Be sure to cover everything well to eliminate little peeks of sun nourishing future weeds. Soak the layers to keep them in place.
Voilà! Decomposition begins in the dark under those layers, earthworms begin to happily tunnel through the dark moist area and the soil begins to loosen up. The grass or weeds break down fairly quickly because they are in the dark under the paper.
Top off the lasagna with alternating layers of “browns” such as fall leaves, shredded newspaper, peat, and pine needles with layers of “greens” such as vegetable scraps, garden trimmings, and grass clippings, just as in a compost pile. Sprinkle it now and then.
Fall is the perfect time to start the process. Just leave it alone until spring, then start planting!