Gardening: How much mulch do you need to spruce up your garden?

Wednesday November 23, 2005

Gardening: How much mulch do you need to spruce up your garden?
By EILEEN WARD, Special to the Eagle
November 23, 2005

To quickly spruce up their messy, hurricane-ravaged landscapes, gardeners can mulch garden beds.

Most people think of mulching just before season in the fall because it adds a uniformity to the landscape, making it appear neat and pleasing to the eye.

But mulching plant beds in the landscape is a good thing to do for many reasons. Mulch retains soil moisture, reduces weed growth, decomposes to add organic matter to the soil and cools the soil. It will cover the sticks and leaves left behind by Wilma, which will decompose and generate some organic matter to help combat excess salt content in the soil.

Mulch should be applied evenly throughout the beds at a depth of 4 inches if it is the first application, or 2 to 3 inches if previously mulched beds are being redressed. Always leave an inch or two of breathing space around the stems or trunks of the plants and trees. Mulch applied next to plant stems can cause rot from the constant moisture, and this could result in their death.

Never mulch citrus trees. Citrus trees prefer clean, raked soil under them out to the drip line. They have very shallow feeder roots that are susceptible to disease when constantly moist.

If the tree develops foot rot, it will attack the bark of the lower trunk, causing it to peel and lift away. In time this will girdle the entire tree, causing death. Once the disease appears, it is not curable. You can try to slow the progress of the disease by cleaning the loose bark and applying a fungicide to the area.

There are many types of mulch to choose from. Chipped mulch is cheaper than shredded mulch. The chipped mulch will wash away much more quickly than the shredded. Shredded mulch will mat together and stay in place while it decomposes. You can get shredded or chipped mulches made from the wood of cypress, eucalyptus or melaleuca (FloriMulch) trees.

Another mulch is pine bark. This mulch, which tends to stay in place a long time, has a more rustic look. Another is pine straw, which is really pine needles and has a soft, fluffy appearance. The various mulches are all different in color and smell, so it is really a matter of personal preference which is the best.

Since the melaleuca is a nuisance tree that we are trying to eradicate from our native forests, FloriMulch would be a good choice environmentally.

Red mulch, which has been very popular since coming on the market, may be hazardous to your health. Two Florida engineers, Helena Solo-Gabriele of the University of Miami and Tim Townsend of the University of Florida, studied the use of lumber debris. Red mulch is made from lumber debris.

Dyed landscape mulch containing wood treated with CCA (chromium, copper and arsenic) — better known as pressure-treated wood — can raise the level of arsenic in soil above safe levels. Walt Disney World will not use treated lumber anywhere it keeps animals. Cooperative Extension agents advise against using CCA-treated wood in vegetable and fruit gardens or in children's play areas.

While not all dyed mulch contains debris from pressure-treated wood, some brands do. If you still want to use this kind of mulch, you should examine it closely, looking for particle board or plywood. If the mulch contains either, try buying another brand or kind. Marco is a small island and we use our ground water through reverse osmosis. You should use red mulch cautiously.

FloriMulch has been around for many years but has been hard to find. I have always been intrigued by this mulch as a good replacement for cypress mulch, which is the mulch most people use.

Cypress trees are very slow-growing, and we are cutting them down at an alarming rate to mulch our gardens. Melaleuca, on the other hand, is a tree we are trying to eradicate from our native forests. This mulch also seems to repel many insects, including termites. And it is not contaminated with arsenic and other chemicals found in the dyed, recycled wood mulches. It decomposes more slowly and is a no-float mulch.

FloriMulch is my top choice for mulching your gardens. It is an easy way to help the environment while improving your property. It is about $1 more a bag than other mulches, but you should just consider that a charitable contribution to helping our native forests.

How much mulch will you need?

By the bag:

— At a depth of 2 inches, a 2-cubic-foot bag will cover 12 square feet and a 3-cubic-foot bag will cover 16 square feet.

— At a depth of 3 inches, a 2-cubic-foot bag will cover 8 square feet and a 3-cubic-foot bag will cover 12 square feet.

— At a depth of 4 inches, a 2-cubic-foot bag will cover 6 square feet and a 3-cubic-foot bag will cover 8 square feet.

In bulk:

— One cubic yard will cover 162 square feet at a depth of 2 inches, 129 square feet at 3 inches, or 81 square feet at 4 inches. To figure area, multiply length by width.

Eileen Ward and her husband, Peter, own and operate Greensward of Marco Inc., a lawn maintenance and landscaping company. Besides completing horticultural courses from the University of Florida, she has a commercial maintenance spray license and is a registered dealer in agricultural products in Florida. To reach Ward, call 394-1413.