Mulch Matters – What and When to Apply in Your Organic Garden
As we get closer to the end of the gardening season for most of North America, it is time to think about mulch. Depending upon where you live, you might automatically think about one material over another when you think about mulch. In the Southeastern US, pine straw is the mulch of choice for many people. It makes sense, because natural longleaf and loblolly pine forests cover most of the southern states. Out west, rock mulch works better with xeriscapes. In the Northern climes of the US and Canada, composted, shredded hardwood bark mulch, or shredded, composted leaf mulch is standard.
Mulch performs a variety of functions in the home garden. It helps protect the soil against erosion by breaking up and soaking up rain and flowing water. It helps keep the soil moist by slowing the evaporation of water. Mulch helps suppress weeds (up to a point) by preventing weed seeds from receiving sunlight needed to sprout. Mulch breaks down into organic matter and humus, which improves the soil structure and provides nutrients to plants. Mulch also regulates the soil temperature–helping soil stay warmer in teh winter and cooler in the summer. A winter mulch is most important in terms of soil erosion prevention, as crops and gardens lie fallow, the potential for valuable topsoil to wash away with winter rains and snows increases.
Types of Mulch
The best type of mulch for your area is one that will decompose and become a natural part of the soil. Rock mulch looks out of place in a northern forest, just as pine straw would look funny in the desert. The importance of mulch type goes beyond aesthetics, though. As mulch breaks down, its components can alter the composition and pH of the soil. This can be especially troublesome for organic gardeners who are trying to work with their natural soil composition when gardening. Pine straw is best for areas with naturally acidic soil, while rock mulch is better suited to the alkaline soils of the west. As these mulches break down, they will work in harmony with the natural soil types. For all but the most alkaline soils, composted leaf mulch is the top choice, if you can get it (or make it!).
Just say NO to Plastic Mulch
Plastic mulch can work fine for large scale production of truck farmed crops such as lettuces, melons, strawberries, etc. It has NO place in the home landscape. The only valuable use for plastic mulch is to sterilize soil to eradicate pathogens. The problem with soil sterilization is that it also kills beneficial soil organisms as well. The biggest reason not to use plastic mulch or landscape fabric is that it does not work. It might work for a year or so, but as soon as a layer of soil begins building on top of it, weeds will again begin to sprout. The plastic will serve as a barrier to organic matter reaching the soil, and will get in your way each time you plant. You will find yourself ripping it out the year after you put it in.
Help your plants get a healthy start by applying the proper mulch for your soil type!