While skimming a magazine from England called Permaculture, I found an article about mounding. The article described how to build mounds in your garden and what materials to use. Over time, the soil becomes richer from the decaying materials. Also, the sides of the mounds provide more space to plant. I realized that I have already done this in my own garden.
When I removed my back lawn many years ago and replaced it with mounds, i used the dried turf from the lawn. I turned the sod upside down for the base of each bed, then proceeded to build the beds up with mulch from my own yard; branches, bark and trimmings. On top of the whole thing I added compost and some garden soil.
These beds were created 20 years ago and are still looking good. I have some major plantings on them, such as small maple trees and lily of the Nile (Agapanthus). Annually, I add compost and dried leaves to enrich the soil.
I also created a mound when I gave up on my huge walnut tree. The squirrels were stripping it and dropping unripe walnuts everywhere, including into my fish pond. After much consideration i had the tree removed.
After the stump was out I started to fill the depression with organic materials from my yard. The first layer was sticks and stumps from small prunings around the yard. Then I added leaves and other garden waste and piled soil on top of the whole thing. Since I planted figs on this area, I call it Fig Hill. It also gets annual composting and other soil added to keep the height.
The sticks and other organic materials that I put in these mounds act like a sponge, absorbing water and holding it for the plants. If you have soil that does not drain well or is hard to work, mounds will help with both of these problems.
With both of these experiences, the results repaid the work. Now is a good time to start such a project in your own yard as you prune and clean up in your garden.
As I learned from the magazine article, one approach is to dig long trenches and then fill them with logs, branches, leaves, grass clippings, straw, cardboard, black and white newspaper, cured manure, compost or other available materials. Then you top it all with good soil. Water well and let the soil and materials start to decompose and settle. Then you are ready to plant vegetables or flowers in your mounds.
The organic content of the mounds gives off heat as it decays and keeps the soil warmer. And the decomposing wood gives off nutrients for years. Hard woods will take longer to decay than soft woods.
An added benefit of the mound method is that it doesn't require tilling. No-till gardens are better for the creatures that live in the soil, like earthworms, so, ultimately, they are better for soil health.
Mound gardens also mean less bending for the gardener.
The article recommended constructing steep beds to avoid compaction from foot traffic. Steep beds create more surface area in your garden for plants, and the height makes easy harvesting. The greater the mass, the greater the water retention.
Some of the beds shown in the article had straw on the top and sides to hold the materials in place. Others had wire sides with plants inserted between the wires. One gardener used shipping pallets to hold everything in place with plants planted between the slats.
Next workshop: “Sustainable Vegetable Growing” (Four-Part Series) on Sundays February 23, March 1, March 8 and March 15, from 2 p.m. to 4 p.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. For more details & online registration go to Online registration (credit card only) or call 707-253-4221.
The UC Master Gardeners of Napa County are volunteers who provide UC research-based information on home gardening and answer your questions. To find out more about upcoming programs or to ask a garden question, visit the Master Gardener website (http://napamg.ucanr.edu) or call (707) 253-4221 between 9 a.m. and noon on Mondays, Wednesdays or Fridays.