Want a garden without the backbreaking task of digging? Try this method.
By Lisa Truesdale
About 40 years ago, an Australian gardener named Esther Deans became fairly well known for her rather unique lasagna recipe. But her recipe didn’t have anything to do with Italian cuisine—it outlined the steps for creating a no-dig garden, which is basically an above-ground garden plot that’s composed of several different organic layers. This technique is sometimes referred to as “lasagna gardening” because, over time, the layers break down into a nutrient-rich soil—much the way actual lasagna is often tastier after the flavors of noodles, cheese and sauce have had a chance to blend together.
Although others had previously advocated the technique—like Masanobu Fukuoka, a Japanese farmer who popularized his concept called “do-nothing farming” in the 1930s—Deans is credited with promoting the concept widely throughout Australia and New Zealand. No-dig gardening is similar to what we call “sheet mulching” in the U.S., and gardening experts say the technique gave rise to the permaculture movement, which advocates farming and gardening principles that simulate the patterns and features of nature.
“With this type of gardening,” says Jeanette Spooner, a garden technician at Otago Polytechnic’s Living Campus in Dunedin, New Zealand, “you’re simply looking at what nature does, then copying it and speeding it up.”
No-dig gardening offers so many benefits that Spooner wonders why more people don’t try it. In fact, she says, turning the soil while digging can disturb the microorganisms and also cause erosion, so it’s best to use the no-dig method whenever possible. With the no-dig method, there’s no backbreaking digging or rock removal to be done, which is especially helpful for children, older gardeners and those with disabilities. It saves time and money, because you don’t have to pay to get the soil tested, experiment with different soil amendments, or endure costly trial and error.
It’s also better for the environment, says Morgan Vondrak, a landscape designer based in California. “People often ask why they shouldn’t just remove the lawn instead. But once the sod is removed, it has to be transported to a waste facility, where it ends up as trash if it isn’t converted into compost.”
And, Vondrak adds, sheet mulching reduces weeds and produces healthier plants. “Healthy, nutrient-rich soils are able to absorb and hold more water, and they reduce the need for fertilizers.”
Vondrak and Spooner agree on the one instance when the no-dig method should not be used: when planting near a tree or other established shrub.
Do not use any ingredients that have been chemically treated, especially if you’re planning to grow food.
“I advise staying at least three feet away,” Vondrak explains. “There are two reasons for this. One, you never want to place any type of mulch directly up to the trunk of a tree or the crown of other plants, because this will block air flow and can cause disease. Two, as the organic material breaks down, it builds up the soil level, and that will cause your existing plants to end up in a hole.”
Spooner and her colleague, Paula Griannah, recently demonstrated the construction of a 3-by-8-foot no-dig garden on the campus of Otago Polytechnic, and we’ve outlined the easy steps for you on the opposite page.
The selected plot needs to be outlined with rocks, bricks or other similar materials that will contain the soil; this step can be done first, although Spooner and Griannah placed rocks around their no-dig garden after a few layers, so that they could position the rocks on the very edge of the cardboard to discourage weeds. A note of caution: Do not use any ingredients that have been chemically treated, especially if you’re planning to grow food.
Cover the area with thick cardboard pieces that have been soaking in water for at least a few hours. Overlap the edges at least 6 inches so there are no gaps where weeds can pop up. (Use non-glossy cardboard without colored inks, and be sure to remove all traces of staples or packing tape.)
Cover the cardboard with a thick layer (¼- to ½-inch) of newspaper that has been soaking in water, overlapping the edges. Don’t use any glossy magazine inserts or colored Sunday circulars. Pour the rest of the soaking water over the cardboard and newspaper. Water thoroughly so the materials can begin breaking down immediately.
Cover the newspaper with a layer of “something woody,” Griannah says. She used wood chips, though in Deans’ book, she suggested using lucerne hay, pea or crop straw at this step. Vondrak suggests shredded wood mulch, or even tree trimmings “if they don’t contain invasive tree seeds.” Water again.
Cover the wood chips with organic fertilizer, like horse or chicken manure. Water again.
Sprinkle lime (also called lime powder, carbonate of lime or garden lime) over everything. “Doing this sweetens everything and encourages worms,” Griannah explains. It also helps adjust the soil’s pH levels so that plants can get the most from the nutrients present. Water again.
Cover the entire area with shredded paper. The contents of your office paper shredder will work perfectly, as long as it doesn’t contain any colored or glossy pages. Water again.
Cover the shredded paper with the leaves and stems of a deep-rooted plant that’s high in nitrogen, potassium and phosphorous. Spooner and Griannah used comfrey, which was growing out of control nearby, because the leaves break down rapidly and provide nutrients right at the roots. Water again.
Don’t use the stems if they’re flowering, though, and take care in handling all parts of the plant, advises Gillian Vine, gardening columnist for the Otago Daily Times. “Some people find the leaves and stems of comfrey to be irritating, so it is advisable to wear gloves.” Vine also adds that “comfrey tends to be invasive, so once you’ve got it, you’ve got it forever.” If it’s not already growing in your yard, see if the neighbors have any they want to get rid of.
Kim Thomas, horticulture technician/lecturer at Otago Polytechnic, explains that comfrey is a “dynamic accumulator,” which means it has the ability to store certain micronutrients, macronutrients and minerals in its leaves; these types of plants are especially helpful for detoxifying soil and gathering essential nutrients. If you don’t have comfrey, she advises, try using another dynamic accumulator, like chicory, stinging nettles or yarrow. You can find a list of other plants online, or ask an expert at your garden center.
Fully cover the entire area with a thick layer of organic compost. Water again. “At this point,” Vondrak says, “some gardeners allow the layers to blend for several months to make sure the lawn and other growth underneath are completely dead before planting new plants.” Your lasagna garden is “finished” when the layers have decomposed to the point that the original layers have become unrecognizable and it looks and smells like fresh earth. Since the process often takes six months or more, Spooner recommends creating your no-dig garden in the fall so it’s ready by the spring planting season. “But some folks will plant immediately after,” Vondrak adds, noting that seeds and flowering annuals are good choices, but that plants with deeper roots will probably do best because “there isn’t much for the shallow-rooted plants to hang onto in the beginning.”