Inorganic Mulches: Are They Right for You?

Mulch is an essential part of any garden or landscape, and an inorganic mulch can be a good option if it meets your gardening needs. But what is an inorganic mulch, and is it right for you and your garden?

What Is Inorganic Mulch?

By definition, organic materials, including mulches, are derived from living matter, while inorganic mulches are not. Organic mulches were once alive and growing and may have been parts of trees, bushes, grains, or grasses, and include mulches such as wood chips, shredded bark, pine needles, grass clippings, rice hulls, shredded leaves, hay, and straw. Inorganic mulches may still be natural, such as rocks, pebbles, and gravel, or could be artificial materials such as landscape fabric, weed barrier fabric, plastic sheeting, rubber chips, and tumbled glass.

The sources for both organic and inorganic mulches may vary. Organic mulches can come right from your own yard, or may be purchased from commercial suppliers. Some municipalities may even offer organic mulch material available at very low cost or free for local residents. Inorganic mulches are also available from many commercial retailers, including garden centers, nurseries, and landscaping companies.

Pros and Cons of Inorganic Mulches

Both organic and inorganic mulches serve the same purposes in the garden and landscape. All mulches help suppress weeds, insulate plant roots, reduce soil erosion, retain soil moisture, and unify the look of a landscape. Before choosing an inorganic mulch, however, it is important to recognize the different pros and cons of these materials to be sure you make the best choice for your mulching needs.

The pros of inorganic mulches and what makes them attractive to many gardeners and landscapers include…

  • Longevity – Inorganic mulches will not decay for years, making them a more long-lasting choice that will not need to be refreshed, topped off, or reapplied frequently.
  • Pest Resistance – Because there is no organic material in these mulches, they do not attract unwanted pests such as slugs, termites, or other insects that can harm a garden or landscape.
  • Recycling – Many artificial inorganic mulches are made from recycled materials, such as shredded tires, making them a conscientious choice for a thoughtful garden.
  • Decorative Options – Inorganic mulches typically offer more color variations and styles than organic mulches, giving gardeners more options to match design preferences and personal style.

At the same time, it is important to acknowledge the possible cons of inorganic mulches, including…

  • Initial Expense – Inorganic mulches are typically more expensive for their initial purchase, though they can be more cost effective in the long run because they need less replacing.
  • Lack of Nutrients – Because inorganic mulches do not decay, they will not gradually add nutrition to back to the soil to nourish nearby plants.
  • Nutrient and Water Limitation – Depending on the mulch used, such as plastic sheeting or large rocks, essential nutrients and water may be prevented from reaching the soil.
  • Less “Natural” Appearance – Depending on how they are used, inorganic mulches can give a garden or landscape an industrial appearance rather than a more pleasing natural design.

It is also important to note that some inorganic mulches may actually pose hazards in the yard, such as chemicals or odors from recycled rubber that can leach into the soil, or tangled shreds from landscape fabric that could threaten wildlife. What types of mulches are used, how they are installed, and what climate they are part of can all impact these potential concerns.

Choosing Inorganic Mulches

After considering the pros and cons of inorganic mulches, there are a few additional factors that should be taken into account before choosing the best mulch for your garden or landscape. Before making a final choice, consider…

  • Your overall budget, including the cost of both purchase and installation of the mulch.
  • Ease of installation, including whether professional assistance may be necessary.
  • Soil type, and what type of mulch can best protect the soil and keep it healthy.
  • Design options and what type of mulch will best enhance the look of your landscape.
  • Permanence of the landscape and how easy it may be to change the mulch in the future.
  • Irrigation type and what inorganic mulch is best for your plants’ watering needs.

Depending on your landscaping needs, it is also possible to combine more than one type of inorganic mulch to find your best solution. Laying a layer of weed barrier fabric first and covering it with gravel, for example, can give you all the benefits of sturdy weed protection without sacrificing the more natural look of rocks. No single type of mulch will work best in every garden or for every gardener, and carefully considering your preferences and needs will help you make an informed, confident decision about inorganic mulches and how best to add one to your landscape.