Never leave your garden naked: Proper mulching protects the soil
By Paul Tukey
With the busiest gardening weekend of the year upon us, it is important to dress for the occasion - dress the garden, that is.
Leaving bare soil around vegetables, perennials, trees or shrubs is never a good thing. That freshly turned or tilled garden may look great for a few days or weeks, but weeds will eventually germinate and take over. Or, worse still, the bare soil can erode in wind or heavy rain.
Numerous materials work well as garden clothing. Coverings such as floating row covers, plastic mulches, rubber roofing underlayments and especially newspaper can make all the difference in successful gardening. Here's a quick primer:
Floating Row Covers
These are made from spun polypropylene, a lightweight material that allows in the necessary light, air and water, while keeping insects out. The row covers also act as mini greenhouses, warming the air around the plants.
Row covers are most often used to cover vine crops of the curcurbit family: cucumbers, melons, pumpkins and squash. Major insect pests include cucumber beetles, squash vine borers, squash bugs, two species of aphids, two-spotted spider mites and whiteflies. You need to protect the crop against insect damage while still allowing pollination by bees, so you'll need to peel back the row covers when the plants are in bloom. Pull the row cover back over the plants at least until the fruit is fully set onto the vines.
Just as the name would suggest, these "mulches" are simply layers of plastic that typically cover the ground to: 1) warm the soil, 2) retain moisture, and 3) eliminate weeds. These come in clear, black, green and red. Clear plastics do the best job of warming the soil in spring, but allow light through and, therefore, weeds can germinate. Black plastic is most common. Certain red plastic mulches have gained favor with tomato growers, because they reportedly reflect beneficial red light from the far end of the spectrum.
Plastic mulches have become time-honored and many people swear by them. I'm not a big fan, however, because the plastic derived from fossil fuels will invariably wind up in a landfill after a year or two in your garden.
This is my alternative to plastic. Really, can there be any higher use for the publication you are currently reading than to wind up providing food for your family?!
Most of today's newspapers are printed with soy-based inks, which biodegrade readily in the soil. I cover the soil in my perennial gardens and between the rows of my vegetable beds with newspaper. Six pages of thickness is recommended to obtain full weed control for a season; any less than that and some weeds will grow right up through.
With the newspaper on the ground, cover the area with a two- or three-inch layer of compost. The compost is just as attractive as any ground wood chips would be and the compost provides all sorts of benefits - including moisture retention, adding nutrients to the soil, boosting the soil biology and improving the soil structure.
Yes, weeds may occasionally germinate right into the compost during the season, but these won't be deeply rooted and can be easily plucked.
Rubber Roofing Underlayment
The last piece of garden clothing, rubber roofing underlayment - or pond liner - is my favorite way to rid an area of weeds or invasive plants. Simply mow the area down and cover it with the 45-milimeter EPDM rubber material, which doesn't allow any air or water to pass through. Within six to eight weeks, the area under the rubber will be completely devoid of any plants and ready to be replanted.
You'll need to work in some fresh compost to get the soil organisms going again, but this method is the most environmentally friendly way of getting rid of nemeses like sumac, bittersweet, poison ivy, loosestrife and other invasives.
Paul Tukey is the publisher of People, Places & Plants magazine and the founder of SafeLawns.org. With comments or questions, email firstname.lastname@example.org.