is rubber mulch bad for the environment

Is Rubber Mulch Bad for the Environment?

Last Updated on August 19, 2023 by Annie Baldwin

Rubber mulch has become a popular landscaping material, but there are concerns about its environmental impact.

This article examines the pros and cons to determine if rubber mulch is truly bad for the environment.

Is Rubber Mulch Bad for the Environment?

Is Rubber Mulch Bad for the Environment?

Rubber mulch is made from recycled tires, which helps prevent old tires from ending up in landfills.

Using recycled materials is often considered an environmentally-friendly practice.

However, some studies have shown that rubber mulch can leach toxic substances as it breaks down, potentially contaminating soil, plants, and waterways.

Key Points

  • Rubber mulch is made from recycled tires which helps divert waste from landfills.
  • However, it can leach toxic substances like metals and chemicals as it degrades.
  • Rubber mulch does not readily break down so it persists in the soil and environment.
  • Alternative mulches like wood chips or gravel have their environmental pros and cons.

What exactly is rubber mulch?

Rubber mulch is a landscaping material made by shredding old, discarded tires.

The shredded rubber pieces are then used to cover gardens, playgrounds, and other landscaped areas.

The material is promoted as an environmentally friendly option since it gives new life to old tires instead of sending them to landfills.

The rubber also does not require any trees to be cut down, as wood-based mulches do.

Additionally, rubber mulch is durable and provides a safe, springy surface for playgrounds.

How is rubber mulch made?

The recycling process starts by collecting used tires from tire shops, junkyards, landfills, and other sources.

The tires are transported to a processing facility where they are shredded into small chunks using large grinding or chopping machines.

The rubber pieces are sorted by size and shape.

Chemicals may be added to give the mulch certain colors.

The result is bagged rubber pieces ranging in size from large nuggets to fine grains of crumb rubber.

Does rubber mulch prevent recycling old tires?

One of the main benefits touted by manufacturers is that rubber mulch gives new life to old tires instead of sending them to crowded landfills.

The United States generates over 250 million scrap tires every year.

Rubber mulch provides an eco-friendly solution by turning this waste into a usable landscaping product.

It also reduces the practice of illegal tire dumping which can lead to health and environmental issues.

Does it contain toxic materials that can leach out?

One of the biggest concerns is that rubber mulch can leach toxic substances as it slowly breaks down.

Used tires contain several potentially hazardous materials including metals, oils, and chemical additives.

As the rubber pieces degrade, these materials can be released into the surrounding soil, plants, and waterways.

Studies have detected concerning levels of zinc, lead, chromium, and other metals in rubber mulch.

High zinc levels have been shown to cause a condition called chlorosis in plants, which affects their ability to photosynthesize.

Other metals and oils can also be detrimental if they build up to toxic concentrations in the environment.

Does it lead to soil, water, or air pollution?

In addition to leaching metals and chemicals, there are concerns that the decomposition of rubber mulch produces toxic organic compounds.

These breakdown products have the potential to cause soil and water pollution, especially if used in large quantities over many years.

Runoff could carry contaminants into nearby streams, lakes, or groundwater.

Rubber mulch is also not a biodegradable material.

It can remain in the soil for many years without fully breaking down.

This differs from wood mulch which decomposes to produce beneficial humus.

Long-term soil health may be affected by the accumulation of rubber particles.

Fumes are also released during the production of rubber mulch, contributing to air pollution.

However, once installed, outdoor rubber mulch does not appear to release significant volatile organic compounds.

Is it safe to use in gardens and around pets or kids?

Based on current research, rubber mulch appears to pose a relatively low risk when used properly in gardens, parks, and playgrounds.

The main concern would be toxic runoff impacting nearby plants and waterways, not direct exposure to pets or humans.

Still, it’s a good idea to keep mulch away from any edible plants.

For high-traffic playgrounds, rubber mulch is touted as a safer choice than wood mulch since it cushions fall.

However, it’s still important to monitor children closely since mulch of any type can get in the eyes or be ingested.

Proper supervision and hygiene practices can reduce risks.

Are there safer mulch alternatives?

For gardeners or communities concerned about the potential environmental impacts, some alternatives include:

  • Hardwood bark mulch – made from natural tree materials but requires deforestation
  • Leaf mulch or compost – produced on-site from yard debris
  • Straw or hay mulch – made from renewable agricultural sources
  • Stone or gravel mulch – inorganic but extremely durable option
  • Coconut coir – made from coconut husks so it’s biodegradable and renewable
  • Paper mulch – made from recycled paper or cardboard but less durable
  • Live groundcovers – can be planted as an alternative to mulch

Ultimately there are pros and cons to every type of mulch in terms of sustainability, safety, cost, and durability.

Rubber mulch is no exception.

Does rubber mulch smell bad?

Some homeowners complain that rubber mulch has an unpleasant or chemical-like odor, especially on hot sunny days.

The smell tends to fade over time as the volatile compounds dissipate.

Using mulch made from recycled tire crumb, rather than fully shredded tires, can reduce odors.

High-quality products that are well-aged and cleaned should have less of an odor.

Is color a concern when choosing rubber mulch?

Rubber mulch comes in a variety of colors, including black, brown, red, green, blue, and vibrant shades like orange and yellow.

Colored mulches are achieved by adding pigments and dyes during production.

Some research indicates that certain dyes or colorants could have ecological impacts.

Consumers may want to choose more natural-looking shades or neutral tones.

Or use mulch sparingly as an accent, not covering the entire landscape.

Does it attract termites or other pests?

There are mixed reports on whether rubber mulch attracts unwanted pests.

Some research indicates that termites and ants are not attracted to recycled tire mulch like they are to wood mulches.

However, organic matter like leaves or needles that get mixed into the rubber could provide food for insects.

Proper installation and maintenance help keep any mulch material pest-free.

Is rubber mulch cost-effective compared to other mulches?

Rubber mulch is more expensive upfront compared to inorganic mulches like gravel or stone.

However, it’s competitively priced against wood mulch and holds its shape longer so it doesn’t need replenishing as often.

It’s also more durable and cost-effective than softer, high-maintenance organic mulches.

For large public projects, the long lifespan of rubber can offset the higher initial costs over time.

Does it require special maintenance or disposal considerations?

Proper installation is important, using at least 3 inches over a weed barrier fabric.

Rubber mulch is fairly low maintenance compared to wood chips and compost.

It does not need annual replenishing.

Since it’s not biodegradable, rubber mulch does not need to be worked back into the soil.

When disposing, it should not go to compost but can be reused or recycled.

How does rubber mulch affect the soil?

Rubber mulch can negatively affect soil health over time as the rubber pieces accumulate and fail to break down.

Unlike organic mulches that decompose, rubber simply sits on top of the soil and does not improve nutrient cycling or soil structure.

Some studies show that the zinc and other metals that leach out of rubber mulch can alter soil ecology.

High concentrations of zinc and lead affect the activity of microorganisms and earthworms that are vital for productive soil.

Rubber may also change soil pH, further impacting beneficial bacteria, fungi, and other soil-dwelling organisms.

Overall, the use of rubber mulch leads to poorer soil tilth and the buildup of persistent synthetic materials.

The rubber chunks prevent water and oxygen from properly accessing plant roots.

Alternative organic mulches improve soil texture, provide nutrients as they break down, and support a diverse below-ground ecosystem.

Is rubber mulch toxic to plants?

There is evidence that the metals released by rubber mulch can be taken up by garden plants and cause toxic effects.

Zinc and lead contamination are chief concerns, as well as runoff containing oils or processing chemicals.

Zinc toxicity leads to a condition called chlorosis in which leaves turn yellow as their chlorophyll is impaired.

Photosynthesis shuts down in affected plants.

Other metals like lead also interfere with enzyme systems and nutrient absorption.

Eventually, plant growth declines, and vegetation dies back.

Rubber mulch is not recommended for use in vegetable gardens or around fruit trees.

Leafy greens and root crops are especially prone to absorbing toxins.

Until more is known about the long-term impacts, it’s wise to use rubber mulch away from edible plants.

Organic mulches like bark or straw are safer around food crops.

How much does rubber mulch cost compared to other mulches?

Rubber mulch tends to cost more per cubic foot than inorganic mulches like stone or pea gravel.

It also usually costs 2-3 times more than shredded wood mulch.

However, rubber mulch lasts longer so the higher initial investment could pay for itself over time.

Here are some ballpark figures on mulch prices:

  • Stone and pea gravel mulch: $2-$5 per cubic foot
  • Wood mulch: $1-$3 per cubic foot
  • Rubber mulch: $3-$12 per cubic foot

Factors like quality, source, color, and regional availability impact exact pricing.

For a large playground or municipal project, the extended durability of rubber may justify the extra upfront price.

Home gardeners may find cheaper alternatives better suited for smaller spaces.

Can rubber mulch be reused or recycled?

Once installed in a landscape, most rubber mulch cannot be reused or recycled.

However, if a project requires removing or replacing rubber mulch, there are a few options to keep it out of landfill.

Some municipalities accept rubber mulch for special recycling programs.

Community mulch recycling centers or scrap tire drop-offs may also take old rubber mulch.

Additionally, it can be reused for projects needing a loose-fill material like horse arena footing.

The best practice is to use quality rubber mulch made from recycled tires initially.

Then maintain the installation so that reuse or disposal is not required.

Unlike wood chips, rubber mulch lasts 5-12 years without needing replacement.

Proper installation over weed barriers keeps the rubber contained.

Does rubber mulch require special installation?

Proper installation of rubber mulch is important to maximize performance and minimize environmental issues.

Here are some key steps:

  • Install over a weed barrier landscape fabric to keep the rubber from mixing into the soil. This also reduces weed growth.
  • Choose a size of rubber mulch appropriate for the location. Larger nuggets work well for landscape beds, while fine grains are preferable for playgrounds.
  • Rake the area smooth and remove sticks, rocks, and debris before applying mulch.
  • Apply at least 2-3 inches of depth, up to 6 inches for playgrounds.
  • Leave several inches of clearance around trees and plants to prevent decay.
  • For playgrounds, it’s recommended to install a shock-absorbing foam pad for safety.

Following manufacturer guidelines for installation and maintenance ensures the rubber mulch will contain properly.

This prevents runoff into gardens and surrounding areas.

In Summary

While there are legitimate environmental concerns about using rubber mulch, particularly regarding contamination of soil and waterways, the material can be an acceptable choice for certain applications as long as best practices are followed.

Consumers should use it sparingly, choose quality products made from recycled tires, and properly install it over weed barriers to prevent mixing with soil.

Rubber mulch is just one option with upsides and downsides.

When making any purchasing decision, it is wise to fully consider all sustainability factors and alternatives.

With proper precautions, rubber mulch can be an eco-friendly way to reuse old tires that might otherwise end up in landfills.

But other mulches, both natural and inorganic, also have environmental benefits that are worth exploring.


What are other eco-friendly mulch options?

Some other sustainable mulch alternatives include hardwood bark mulch, straw, leaf mulch, compost, gravel, stone, coconut coir, and live groundcovers. Each has its environmental considerations, but these are generally safer options than rubber.

Can rubber mulch be composted?

No, rubber mulch cannot be composted since it contains synthetic ingredients and does not biodegrade. Rubber mulch must be disposed of through recycling centers or landfills. Never put rubber mulch into garden compost piles.

Does mulch made from recycled tires contain chemicals?

Yes, recycled tire rubber contains metals, oils, and chemicals that can leach out of rubber mulch over time. These include concerning materials like zinc, lead, and chromium.

What precautions should be taken with rubber mulch?

Use rubber mulch in moderation, choose more natural colors, prevent it from mixing into the soil, dispose properly, and monitor nearby gardens and waterways for any signs of contamination from runoff.

At GreenChiCafe, we are passionate about protecting the environment and conserving natural resources. Check out our website for more tips and information on living an eco-friendly lifestyle. We care about the planet and believe in making choices that nurture rather than harm our fragile ecosystems. Together we can make the world greener!

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