A Weed Barrier is:
As a landscape company that specializes in landscape installations and maintenance, weed barriers are a regular topic of conversation with our customers. A weed barrier is typically a large tarp made of solid or porous material that is placed underneath the soil of a garden bed, acting as a barrier to any weeds which spread underground.
They can be very useful, but they do have some drawbacks.
A few Drawbacks
The biggest of these is that they are only able to prevent weeds from entering beds from below ground. It’s still possible for weeds to invade garden beds from above, either by seed or over ground spreading runners. So while it may reduce the overall amount of weeds, it won’t keep your garden weed-free. Additionally, weed barriers don’t last forever. Over time they break down allowing determined weeds to break through. Because of this, barriers need to be replaced every 10-12 years, which can be a challenging task in beds containing perennials or larger plants.
Consider Long Term Goals
While a barrier can be effective at keeping weeds out, it may also keep things in. This can be a fantastic help in areas full of landscape rock, since it prevents the rock from sinking into the soil and reduces the need for replacement rock. On the other hand, the barrier will also keep nutrients and moisture in, creating a nutrient deficient area directly beneath the bed. In landscapes with deep rooting trees and shrubs, these ‘foodless’ pockets of soil can negatively impact the overall growth and performance of larger plants. It’s important to carefully consider the long term goals for a bed before using a weed barrier.