Using mulch preserves water and protects and improves soil quality, but weeds growing through the mulch can ruin your garden. Property owners and landscapers therefore use different materials such as plastic, cloth, and newspaper under mulch to prevent weed growth. But which one is best for your home?
Plastic, newspaper, and cloth can all be effective weed barriers. However, landscaping fabric and plastic can get clogged with dirt, blocking the exchange of moisture and oxygen to the soil. Newspapers, meanwhile, are bio-degradable and won’t hinder plant root growth.
It’s important to consider the potential downsides of any addition to your garden, so let’s take a closer look at how plastic, newspapers, and cloth work and their potential effects.
Landscaping Fabric Under Mulch
While mulching is a natural gardening technique to prevent weed growth, you might need extra help from a weed barrier cloth. Landscaping fabric (on Amazon) is a popular weed-blocking material used under mulch.
Breathable landscaping cloth complements the function of organic mulch such as grass clippings, tree bark, straw, or compost. The artificial mulching layer blocks light going through and, in this way, suppresses weed growth. With no nutrients and light, weed seeds can’t sprout.
Gardeners prefer landscaping fabric over plastic for several reasons. The breathable fabric allows some water and air to flow into the soil. When properly installed, the weed barrier won’t kill the roots of your plants.
While landscaping fabric is popular with gardeners, the use of foreign material could have devastating effects over time. The small perforations designed to allow moisture and air exchange can quickly get clogged with dirt. With no exchange of oxygen and moisture through the mulch, the quality of the soil deteriorates.
Lack of breathing space through the landscaping fabric could suffocate the soil below and prevent nutrients seeping through from the decaying mulch. In addition, microorganisms that are helpful in soil breakdown can’t thrive in such conditions. While the fabric might effectively smother weeds, the lack of nutrients in the soil could also kill the plants on your landscape.
Furthermore, landscape fabric under mulch doesn’t have a 100% success rate against weed growth. You may still notice weeds sprouting through the pores.
Experts say that proper mulching depth (between two and four inches) is sufficient to keep your garden weed free. Mulch breaks down naturally and combines naturally with other matter in the soil to promote healthy plant growth.
Newspaper Under Mulch
Gardeners who want an eco-friendly physical weed barrier tend to opt for biodegradable newspapers under the mulch layer.
If you have a weed problem in your garden, use old newspapers to suppress existing weed from growing. Old newspapers prevent runners from sprouting, which can ruin your beautiful garden. Laying newspaper layers under mulch also smothers weed seeds and prevents them from germinating.
Newspapers are bio-degradable and won’t create a mess in your garden. Within a few weeks, the papers under the mulch start to break down without any harmful effect on the ecosystem. The newspapers don’t hinder the growth of plant roots. As the papers break down, the natural exchange of air and moisture between the atmosphere and the soil continues.
Using newspapers in your landscape saves the cost of chemicals required to control weeds. If you want a more environmentally-friendly weed controlling technique, using newspapers under mulch offers myriad benefits.
Plastic Under Mulch
Plastic sheeting (on Amazon) is the most common weed barrier used in landscaping. For the best results, gardeners lay the physical barrier under mulch before planting. Other landscapers install the plastic sheeting after planting before mulching.
The idea behind plastic sheeting is to deny weed seeds light and suffocate them. The sheeting prevents any weeds that start growing from reaching the surface and ruining the landscaping. Before laying plastic under mulch, prepare the garden by tilling the soil, removing any weed, and adding fertilizers as required.
To allow healthy growth of the plants, landscapers puncture small holes in the plastic sheeting using a fork or other sharp tool. The holes allow air and moisture entry into the soil without letting weeds sprout.
Is plastic under mulch a good idea? While many landscapers recommend the installation of plastic sheeting under mulch, the material might have negative effects on your landscape.
Here are some reasons plastic under mulch might not be a good idea:
- Non-Biodegradable Material
Plastic is not biodegradable and, unlike with newspapers or cardboard under mulch, you’ll struggle to remove it from your garden. The material doesn’t break down easily, and it’s harmful to the environment. If you want to plant something else a few years down the line, you’ll have to remove the torn plastic layer.
- Poor Soil Quality
The tiny holes perforated on the sheeting might be ineffective at allowing sufficient air and moisture through to the soil. Lack of nutrients in the soil kills the plant roots and soil microorganisms, which affects the quality of your garden. The holes could also get clogged with time, thereby killing microorganisms in the soil.
- Excessive Heat
One of the reasons landscapers use plastic under mulch is to raise soil temperature. The plastic sheet might work to warm up the soil but the heat could be counterproductive with time. The plastic conducts heat, and you might end up damaging the roots or killing microorganisms in the soil.
Plastic under mulch is a creative idea to kill weeds and allow your plants to thrive. However, the side effects could end up ruining your garden and increasing the work you need to do when replanting. Plastic materials can also emit harmful compounds into the ecosystem.
Why Mulch Decay Is a Good Thing
Mulch decay is a natural way to replenish your garden’s soil for better plant quality. In the presence of water, organic mulch decays, adding nutrients that enrich the soil in the process. The nutrients boost the growth of your landscaping plants while also encouraging the growth of beneficial microbes. These microbes reduce harmful pathogens in the soil and prevent disease.
The humus matter formed in the decay process also feeds beneficial microorganisms and improves water absorption by preventing crusting of the soil. The fine decayed material also allows easier movement of water through the soil.
The use of artificial weed barriers might affect the absorption of essential nutrients from the mulch decay. When you install plastic, newspaper, or cloth under mulch, make sure the material is permeable to allow the decaying mulch to integrate into the soil beneath.