by Colleen Vanderlinden

Created on: February 07, 2007   Last Updated: April 18, 2007

Mulch does so many things: it keeps weeds at bay, cools the soil, and makes a garden look finished. There are so many different types of mulch: everything from black plastic to grass clippings can be used to mulch your garden. This article will cover some of the most popular mulch materials, and offer the pros and cons of each.

Shredded Bark
This is typically sold as cedar or cypress mulch. It is an attractive, natural color, and, when newly applied, has a wonderful woodsy aroma. It is very effective at weed control and water retention, because the pieces knit together, but at the same time, it resists compression. It is also inexpensive.

Straw
Straw is a wonderful mulch. It is not the most attractive, but it is great for vegetable gardens. To get the most weed control and water retention, however, you will need to layer it deeper than the other mulches. For straw, five to six inches is ideal, because it is so light and fluffy. One caveat: be sure you are getting "straw" and not "hay." Hay contains weed seeds, which will inevitably be sprouting up all over your garden.

Grass Clippings
Free and plentiful, grass clippings make great mulch. They decompose quickly, giving your soil a quick nitrogen boost. If you don't find them especially attractive, you can always use them to mulch the veggie garden.

Pine Needles
This is great mulch because it doesn't mat down, is easy to find (it is also sometimes called "Pine Straw") inexpensive, and gives the landscape a very natural look. If you have pine trees, you have a free source.

Leaves
Another plentiful, free option, especially if you have lots of trees. A mulch of leaves lends a natural look to your beds, reminiscent of the forest floor. The best way to use them is to shred them with your lawnmower or a shredder before you apply them to the beds. If you apply them whole, they tend to mat down and can prevent water from getting through to the soil.

Cocoa Bean Hulls
These are attractive, lightweight, and, if you're a chocolate lover, you will love the aroma they give off when newly applied. They are not my favorite for a few reasons. First of all, they are not always easy to find. Secondly, they are the most expensive of the mulches listed. And thirdly, and most importantly, they are toxic to dogs. According to an ASPCA study, dogs that ate cocoa bean mulch became ill, vomiting and experiencing muscle tremors.

Bark Nuggets
These take the longest of all of the mulches listed to decompose, which means you don't have to apply them as often. However, they tend to wash away in heavy rain or watering, and may not be the right look for every landscape.

Other mulches, such as rocks, gravel, shredded rubber from tires, or black plastic may keep the weeds down and help conserve water, but they are inorganic, which means that they don't break down into anything that the soil can use. They don't contribute to overall soil health the way the organic mulches listed above do. And, since healthy soil is the basis for a healthy garden, it is better to go with an organic mulch. Besides, other than the stones, none of these look particularly natural in the landscape. For a more modern or utilitarian landscape, these might work.

So there it is: a mulch primer. No matter which type of mulch you choose, your garden will thank you for it!

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