• Inorganic or Fabricated Mulches

o Aluminum foil. As a mulch type its use is limited primarily to vegetable plants where research findings have indicated a significant reduction in insect pests, such as aphids, and viruses carried by insects.

o Black polyethylene. This mulch type is used in vegetable and vine crop production (cucumbers and melons), but is not recommended for use in the landscape unless the soil is very well drained since air cannot penetrate polyethylene film, and soils remain too wet.

o Landscape fabrics. Landscape fabrics are also known as geotextiles or weed barriers. There are two types of fabrics available: woven and non-woven polypropylene polymers (synthetic material). These types of mulches are limited in use to an undercover for a more decorative mulch such as shredded bark because most polypropylene polymers are readily oxidized (combined with oxygen and degrades) when exposed to ultraviolet light. Some fabrics, however, are surface coated with carbon black and thus offer a degree of resistance to degradation from ultraviolet light.

o Other inorganic materials: stone, chips, pebbles, gravel. These are available in many sizes and colors, and are utilized for color and texture changes, particularly in plantings in blacktop covered areas. All are fire resistant and have application near public entrances to buildings, along sidewalks and in shopping areas. However, they offer no value as breakdown products in the soil, which is true of all inorganic mulches.

• Organic Mulch Products

o Animal Manures. While you can go to a local farm for manure, manures are dried or dehydrated and sold for soil amending, mulching, or fertilizer purposes. Weed seed are sometimes introduced with manure.

o Composts. Although compost is not usually packaged for retail use, grass clippings, leaf mold and used mushroom composts are available as mulch.

o Composted municipal sludge. This material is now available as a mulch with trade names such as EarthlifeTM, ComtilTM and TechnaGroTM, among others.

o Hulls, cobs, shells. This group of by-products, to a large degree from the food industry, includes such mulches as cottonseed, buckwheat, cocoa-bean, peanut or rice hulls, crushed corn cobs, spent hops, tobacco stems and similar products. All have been used extensively for mulch and are usually inexpensive. The disadvantage is that availability is typically limited to a local area.

o Sphagnum peat moss/muck peat. Sphagnum peat moss comes from mosses (sphagnum, hypnum, etc.) and contains long fibers which resist decomposition. Muck peat originates from well decomposed plant material that once thrived in swamps such as cattails, reeds, sedges and other water plants. While sphagnum peat moss is usually quite acidic, muck peat is usually neutral to slightly alkaline, is well decomposed and is dark brown or black with almost no fibers. It is fine in texture, dries quickly and can be blown away by the wind when used as a mulch.

o Pine needles. The needles of pine trees as well as shredded cones make an excellent mulch particularly for evergreens and plants that thrive in acidic soils.

o Straw. Straw and hay are used for winter protection of perennials, strawberries and small plants. If left as a permanent mulch, additional nitrogen (one pound of nitrogen per 1,000 square feet) is suggested, since this material decomposes readily. Weed seed can be introduced from straw, hay and grain crop residues. Salt hay, available along coastal states, is a very acceptable mulch.

• Wood products.

o Shredded, chip, or chunk bark. This material is by far the most popular landscape mulch due to its appearance, serviceability and cost. Included are shredded hardwood and cypress bark, chipped and chunk pine, and fir and eucalyptus bark.

o Wood chips or shavings. They have become available through utility companies and are usually not available in packaged form. Since they consist, along with sawdust, of more wood than bark, they decompose rapidly and should be supplemented with fertilizer at the rate of one pound of actual nitrogen per 1,000 square feet of mulched area.

o Waste wood. Materials such as used pallets and other wood pieces that normally would have been taken to a landfill are now shredded and metal objects are removed. The resulting chips are colored to match pine, hardwood, cypress or any other mulch product on the market. This material also decomposes faster than bark and requires the addition of nitrogen fertilizer.