Should I Put Plastic Down Under Pine Needles to Keep Weeds From Growing?

Benefits

• Black plastic is inexpensive to buy and easy to install. It conserves moisture in the soil and prevents some weed growth. It is readily available at hardware and home improvement stores.

Drawbacks

• Black plastic mulch under pine needles tears easily and becomes damaged, requiring replacement within two or three years. It doesn't decompose, making it less than ideal from an environmental standpoint. Sunlight, oxygen and rain can't permeate black plastic, creating unfavorable conditions for growing plants. It also heats the soil in the summer beyond optimal temperatures for most perennials and shrubs. Weeds grow through holes in the black plastic, or in soil in the pine needles. These weeds are more difficult to remove than those emerging from bare soil.

Alternatives

• Consider landscaping fabric as an alternative to black plastic under pine needles. Landscaping fabric blocks weeds, but allows sunlight and rain to reach plants. Although it is more expensive to purchase, it doesn't rip and lasts longer. Another option is to place the pine needles directly on the soil in a 2- to 3-inch layer. The pine needles alone suppress many weeds, and the weeds that come up are more easily removed.

Recommendations

• Avoid using black plastic under pine needles.The one practical application for black plastic is in the vegetable garden where it is used to warm the soil for tomatoes and melons. In perennial and annual flower gardens, black plastic becomes a nuisance, especially if you wish to plant new flowers or amend the soil annually. If you choose to use black plastic or landscaping fabric, stretch it evenly over the soil and secure it with landscaping pins. Cut it as needed to fit the bed.