Gardener’s Gold

If you have deciduous trees in your garden, you might be fretting these days over the task of raking and disposing of the fallen leaves. You might instead welcome this form of nature’s bounty, because your trees have contributed the raw material for an excellent natural resource for your garden: leaf mold.

Leaf mold, which is simply partially decomposed leaves, can be used as a mulch to discourage weeds, retain moisture and insulate the roots of plants from the coldest weather. It can also be used as a pH-neutral soil amendment, like compost, to retain moisture, improve soil texture, add nutrients and support the growth of beneficial soil organisms of all kinds.

The question, then, is how to convert the fallen leaves to leaf mold.

The raking can’t be avoided, but the rest of the task could take any of several forms, depending on the gardener’s patience and available space, and the kind of leaves. Some leaves, including oak and holly, contain relatively high levels of cellulose and are slower to break down.

The easiest conversion of leaves to leaf mold is to pile the leaves in an out-of-the-way location and let them decompose on their own schedule. This process could require a year or more, but could be hastened in several ways, singly or in combinations.

  • Leave your leaf pile in a shaded location, or cover it with a plastic tarp. This helps to retain moisture, which supports the decomposition process, which depends upon the work of fungi.
  • Water the leaf pile occasionally, to maintain a damp (not soggy) condition.
  • Turn the pile occasionally, to expose the contents to oxygen.
  • Shred the leaves. Smaller pieces have greater exposure to the air and moisture, and therefore break down faster. Run over the leaves with a lawn mower—almost any kind would do—or put them through an electric leaf shredder or leaf blower-vacuum. My American Sycamore’s big leave tend to block my blower-vacuum, so they have to be roughly shredded first with the mower. For smaller quantities, place the leaves in a trashcan and shred them with a weed whacker.
  • Add nitrogen. Old dry leaves are almost all carbon, so the addition of nitrogen will speed their breakdown. Add green vegetation or nitrogen-rich fertilizer. Dry chicken manure has twice the nitrogen content as horse or steer manure.

The leaf mold is ready when it has become soft and crumbly. Use it to mulch your plant, spreading it about three inches deep (not too close to the base of the plant). Or dig a similar amount into the soil; this could be easiest when preparing a new bed, and is particularly helpful for improving soil that contains an excess of clay or sand. Leaf mold also could be included in containers to lighten their weight.

Enjoy gardener’s gold in your garden!

Mulch for Much Easier Gardening

Mulching represents a gardener’s not-so-secret strategy for achieving the universal objective: a low-maintenance garden.

If your garden is time-consuming, frustrating and disappointing, it probably needs mulching.

Several other possible causes should be considered: nutrient-poor soil, lack of irrigation, inappropriate plant selection, etc., but let’s focus for the moment on mulching.

A three-inch deep layer of an organic mulch between plants discourages weed growth, conserves water and, in time, breaks down to add nutrients and texture to garden soil.

We should not ignore the downsides of mulching. For example, a larger garden will require several cubic yards of organic mulch, leading to significant charges from a landscape supply company for the material and its delivery. In addition, distributing the mulch within the garden, while not difficult, consumes time and energy.

One more downside: organic mulches decompose in time, so the time and expense will have to be incurred again. Finer mulch materials break down faster than coarse materials.

Some organic mulch is free, e.g., disease-free wood chips that tree services will dump on your property, upon request (to avoid landfill charges), or seaweed harvested during low tide. Wood chips might be regarded as less attractive than finer mulches, and seaweed, although excellent in nutrient content, often is troublesome to gather, buddy and smelly.

A landscape supply company will offer a variety of organic mulches in bulk, e.g., redwood sawdust, shredded cedar, fir bark and gorilla hair (shredded redwood bark, really), in a range of sizes and prices.

Another option is cocoa shell mulch, which is available in bags of two cubic feet for about $5.00. This material looks good, emits a nice fragrance and breaks down slowly, but contains theobromine, a natural compound that if eaten is highly toxic to dogs and cats.

The gardener could consider each of the available options, and perhaps try a sample bag in the garden.

Home supply stores offer organic mulches in bags of two cubic feet of material. These can be appropriate for smaller beds, but for larger projects will be more expensive than bulk materials. To move one or two yards of mulch, it’s good to have a friend with a pickup truck.

Gravel mulch might be preferred for a rock garden or succulent garden. For a rock garden in particular, gravel mulch simulates scree, the debris of broken rock seen on mountain slopes.

Like organic mulches, gravel mulch discourages weeds, conserves moisture and looks better than bare soil.  Gravel is much more expensive per cubic yard than organic mulches, but a one-inch layer should be enough and gravel doesn’t decompose. Gravel mulch is difficult to remove, so for practical purposes treat the installation as permanent.

Enjoy your mulched garden.

More

Estimating Mulch Needs

To decide how much material you will need, estimate the surface area of the garden bed(s) to be mulched: length times width (in feet). Multiple by the intended depth of the mulch layer: for a three-inch layer, multiply by .25. Finally, convert cubic feet to cubic yards by dividing by 27.

Example: a 12 feet x 18 feet garden bed has a surface area of 216 square feet. For a three-inch layer of mulch, .25 x 216 yields 54 cubic feet. Divide by 27 to determine a need for two yards of mulch.

Seaweed Mulch

An interesting article, How to Use Seaweed to Mulch Your Garden, is available on the website for Eartheasy: Solutions for Sustainable Living. Gardeners who live close to the beach might wish to try this mulch material, but it seems too smelly and buggy for my taste. It also decomposes into slime rather quickly.