The Ultimate Guide to Mulch

Generally speaking, mulch is anything that is spread around or over soil as cover. It has become an important part of gardening and landscaping. Through the years, however, mulch has been redefined to include the surfacing of playgrounds, parks, and horse arenas.

It's become a multi-purpose material used to enhance soil properties for growing plants, to beautifying landscapes, through to cushioning potential falls in playgrounds, recreational parks, and horse arenas.

It's become such a big business that the use of mulch is not without its share of controversies, which we will get to a little further down in this eBook. At this point, a closer look at the different types of mulches and their uses can tell us more about their origins and uses.

*Please note that links to resources further explaining certain terms and concepts can be found throughout the text.

A. Types of Mulches

Certain kinds of mulches have been around since gardening became a widespread practice. Of course, organic mulches have existed longer than their synthetic counterparts, since the former can be easily sourced from nature.

Organic mulches decay and decompose over time. They are made from natural or biodegradable materials. Synthetic mulches either do not decompose or else do so very slowly, and are usually the products of industrial recycling and manufacturing.

Wood is a popular mulch option. It typically comes in the form of chips, either as coarse byproducts of tree pruning, or as more uniformly processed byproducts of untreated timber.	Grass clippings are collected and used as mulch after a lawn is mowed or trimmed. They are usually mixed with other composting materials like fallen leaves and soil.
Leaves are raked and then spread over garden soil to act as mulch. Because they are light enough to get blown by the wind, they are often shredded into more manageable pieces.	Straw is collected into hay bales and spread onto the ground as winter covering for gardens.
Rock mulches can come from pebbles, river stones, and gravel. The variety of sizes, colors, and textures of this material allow for many gardening and landscaping possibilities.	Paper and cardboard are common recyclable mulching materials. They can be soaked in water to increase their weight, and then applied as the base layer for heavier mulching materials.
Bark is a practical organic mulching option since it's readily available in landscapes and gardens with trees. They are typically used in layers.	Other common organic mulches include peat moss, sawdust, and pine needles.
Plastic mulch is used to suppress weeds in gardens and landscaping. It also helps regulate irrigation for large-scale vegetable gardens. Currently, biodegradable or compostable plastic mulches are being created to respond to environmental issues and awareness, and in accordance with ASTM standards.	Recycled rubber is fast gaining popularity as an alternative sustainable mulching material. It is made from either shredded old tires or sneaker soles.
Landscape fabrics or plastics are also known as "weed cloth" that are spread over garden soil and pinned down. They are designed to work with organic materials and can last for a decade.

B. Popular Uses for Mulch

As diverse as mulching materials are, so have their uses become. Over time, mulch has evolved from just being garden material to becoming playground surfacing, horse arena infill, and even military training surfaces.

Gardening	Garden mulch, whether it is natural or synthetic, is used to improve moisture retention in soil so that plants can benefit from it. It's also designed to reduce or prevent weed growth altogether. Mulch is also an effective soil insulator.
Playground/Athletic Arenas	Safety is a top concern in playground surfacing, and mulch can efficiently address this. Different kinds of mulches offer different levels of fall-from-a-height shock absorption and protection. As for athletic tracks, rubber mulch also offers the kind of resiliency that can improve a runner's performance while protecting feet and legs from hard impact.
Landscaping	In landscaping, mulches are used to add visual impact and decorative appeal to homes, businesses, and public places. The many textures, shapes, and colors of mulch make this possible.
Horse Arena	One of the surprising new uses for mulch is as equestrian infill. Shock absorption and better performance are the main reasons for its use as horse arena surfacing. Rubber mulch in particular offers these benefits.

For all its benefits, mulch also offers some drawbacks. This is true for both organic and synthetic mulch, so it is up to you to weigh their pros and cons and consider your needs before deciding which one to invest in.

A. Benefits

Ordinary mulch users and experts alike have weighed in on the various benefits mulching offers. Here are some pros based on its more popular uses.

B. Drawbacks

Mulches also have certain disadvantages, as illustrated by their common uses below.

If you're in the market for mulching material, whether it's for your garden, landscaping needs, or for something bigger like a playground or athletic arena, you will have to weigh the relative merits of organic and synthetic mulches available. Below are some of the most common arguments for and against both organic and synthetic mulches.

A. Why get organic mulch?

• It is cheaper or can be had for free.
  Fallen leaves, straw, rocks, grass clippings, bark, and many organic mulching materials typically cost less than synthetic mulches. If you're resourceful, you can have them for free by collecting them yourself or gathering them where they're plentiful.
• It contributes nutrients to soil.
  Because it decomposes, organic mulch passes nutrients to the soil and plants as it rots (which synthetic mulches can't do).
• There are more organic options.
  You won't have to go to a store to select what you need. You can simply mulch with what you have or what's readily available, thanks to natural resources: trees, grass, rocks, sand, etc. around you.
• It is all-natural.
  Your garden will look, feel, smell, and be as nature intended it to be.

B. Why get synthetic mulch?

• It is cheaper in the long run.
  Because you won't have to spend too much on top-ups, replacement, or additional gardening peripherals like pest control and fertilizer, synthetic mulch ends up costing you less over the years. This is true of landscape fabrics and rubber mulch, which can last ten years without replacement.
• It offers better shock-absorption.
  Rubber mulch provides a softer alternative to traditional mulches which don't offer much by way of protecting from falls. With proper installation and adequate depth (around six inches), a rubber mulch surface will give up to 16 feet of critical fall height protection compared to gravel or wood mulch. Even the playground at the White House uses rubber mulch.
• It requires less maintenance.
  Rubber mulch and landscape fabric stay put because it won't float away in rainwater, freeze in winter, or get blown by the wind. A bit of raking now and then is all you need to do.
• It recycles unwanted landfill material.
• Tons of old tires have become a landfill problem, which is why recycling them into rubber mulch became a viable solution. Due to the process of recycling and repurposing rubber mulch undergoes, some states like Kentucky have incentivized its use.
• It is EPA-endorsed. The Environmental Protection Agency (EPA) has actually endorsed the use of rubber mulch for playground surfaces. The agency has also done surface and atmospheric tests on playgrounds using rubber mulch, and found no significant adverse human or environmental effects.

To gauge the performance of rubber mulch against popular organic materials like rocks, pea gravel and wood chips, here are comparison charts that list their relative merits.

Rubber Mulch vs Pea Gravel

Protection from falls	At just 6 inches in depth can provide protection from falls from over 12 feet. Unlike pea gravel, temperature does not affect rubber mulch and performs just as well in cold weather as is does in warm climates.	At depths of 9 inches or more can sufficiently reduce the impact of a fall. Can become quite hard in cold weather which can affect impact.
Maintenance	Doesn't break down and doesn't compact. No need for annual replacement. General inspection of the surface, raking the material to ensure it stays at a consistent depth, and periodic top up every few years	Will begin to break down into smaller particles over time. Can cause "hard pans" made of dust from broken-down gravel, which is difficult to break apart and can be dangerous. Requires annual replacement.
Visual appeal	Available in a host of both earth tones and bright, vibrant color options for playgrounds, gardens, and athletic or horse infills.	Provides a natural, organic type of appearance. The material is usually grey in color but depending on the source of the stone, some color variations may be available.
Price tag	Comes with a higher initial purchase price but can often be offset over time due to reduced maintenance and top up requirements.	Falls into the lower cost category with pea gravel being the lowest cost option. Requires annual top up.

Rubber Mulch vs Rocks

Nutrition	Doesn't absorb water or fertilizer so all soil and plant needs goes right into them. Doesn't decompose so offers no nutritional benefits to soil and plants in a garden.	Insulate cold-sensitive plants with warmth and help them thrive even in harsh conditions. While organic, also do not offer nutrients that enrich soil and plants.
Lifespan	Offers a longer shelf life because of sufficient weight that doesn't float away or get blown by breeze. Can be used for mulching and landscaping purposes for over a decade without degrading.	Sufficiently heavy so can stay put for longer period compared to other lightweight mulches.
Durability	Is the result of recycling tires, therefore made to withstand harsh weather conditions, making it ideal for low maintenance mulching purposes.	Typically comes from hardy volcanic deposits. Can withstand high winds and harsh weather conditions
Price tag	Initially has a bigger price tag per sq.ft. but requires less top ups and replacement in the long run.	Can be sourced anywhere at any time. Can stay in place far longer than other organic mulches, so requires less top ups and replacement.

Rubber Mulch vs Wood Chips

Weed/mold control	Can help dehydrate unwanted seeds and protect the plants in your garden. Lets water pass straight to soil so lesser chance of mold and fungi.	Because of decomposition, could create a more favorable environment for weeds to thrive, and mold/fungi to grow.
Nutrition	Merely provides a layer or cover for your garden and does not enrich it with nutrients. Chemicals such as zinc from the rubber might find their way into the soil and affect soil and plant quality.	When treated or colored with chemicals, could prove harmful to both soil and plant life. Nutrients in organic, untreated wood chips can serve as fertilizer and integrate into the topsoil, thus encouraging biodiversity.
Protection from pests	Doesn't rot so pests are not attracted to it, will not build a home in it or make it their primary food source.	Attracts termites and other insects that can ruin not just your garden, but also wooden parts of your home.
Attractiveness	Comes in a wide variety of colors. Tends to hold its color much longer, and as long as 10 years.	Has the natural look, feel and smell of real organic materials. Can be treated or colored to enhance landscaping.
Price tag	Initially will cost more than wood chips but significantly reduces maintenance and replenishment costs.	Initially cheaper, though wood chips might need to be replaced every two years because they decompose. Cost of termite control, top ups, or replacement can add to expense.

Mulch ado about nothing? Perhaps no other consumer product has polarized the mulching community as much. Aside from the natural vs synthetic mulch debate, the advantages and disadvantages of each type of mulch also affect gardening, landscaping, and infill decisions.

Gardeners, landscape professionals, and those who regularly use mulches recognize that no two mulching materials (whether manmade or from nature) are created alike. What may generally work for one garden or playground may not work for another.

Other factors like soil quality and the weather should also be considered. This chapter looks at both the common complaints and the specific problems of different kinds of organic and synthetic mulches.

A. General complaints about organic mulch

• Molds.
  Certain natural mulches like shredded coconut shells attract molds when they get wet or as they age. Slime molds in particular produce small spores that dry up and spread around quickly.
• Sour smell.
  The decaying process brings about an unpleasant odor in your garden or playground - not a good olfactory experience in designated rest and recreational zones.
• Artillery fungus.
  Aptly named for its ability to shoot microscopic spores as high as the second story of a house, artillery fungus is difficult to remove and stubbornly sticks to any surface it lands on. It thrives on decomposing matter.
• Constant maintenance.
  Decomposing mulches need to be replaced regularly to discourage fungal and weed growth (and general mess). Lightweight ones that get displaced by wind or water need annual topping up or replacement.  
• Attractive to rodents and insects.
  Wood, shredded husk, straw, and other natural materials which rodents and insects (especially termites) can get their food or shelter from will attract them on a regular basis. This is especially problematic if you have fruit-bearing plants, outdoor structures and furniture made of wood, and grain/seed storage.
• Insufficient shock absorption.
  In playgrounds and athletic arenas, organic mulch surfaces don’t offer the kind of springiness rubber mulch does and therefore do not absorb shock as efficiently. Others, like straw and grass clippings, can become slippery when wet and even add to the likelihood of falls.

B. Specific problems of different types of organic mulches

C. Common complaints about synthetic mulch

• Not pet-friendly.
  Consumers have raised concerns about pets swallowing rubber mulch or developing allergic reactions when they come into contact with it. In the case of landscape fabric, sharp claws and fangs can puncture holes in the cloth, which allows gaps for weeds to germinate.
• Looks fake.
  When inspected closely, rubber mulch, landscape fabric, and plastic turf can look and feel (and smell) too industrial for many people. Rubber mulch usually comes in a variety of colors, though many landscaping and gardening professionals prefer browns and greens that echo the colors of bark, soil, and leaves. Landscape fabric can be combined with or hidden under organic mulches.
• Can leach chemicals into the soil.
  Clinical research and laboratory studies have detected the presence of zinc, cadmium, and lead in rubber products, which could affect soil and water quality. There is still no conclusive evidence for human toxicity levels, though.
• Health concerns.
  Consumers worry about sensitivity to rubber and plastic products, irritation of the skin, eye, and mucous membranes, and other adverse effects of synthetic mulch exposure.
• High price tag.
  Even if its long term benefits outweigh the initial expense, many people find rubber mulch’s price tag too steep (which is around four times higher than wood chips’).

D. Specific problems of different types of synthetic mulches

Different mulching materials make for different mulching techniques, but there are general rules to follow if you don’t know where to begin.

A. How much mulch is needed?

First, consider what you will be using the mulch for: a garden, for landscaping, or for playground surfacing? This will help you determine the depth and width of the area that needs mulching. Multiply the length of the area by its width to figure out the square footage. If the area is uneven, you can divide it into smaller rectangles, then add up the total of all the rectangles to arrive at the square footage. Or, you can simply use a square footage calculator to compute for it.

Multiply the square footage by the thickness in inches you want to apply.
Online conversion calculators such as this one can help you convert weight, length, area, and volume so you can come up with the proper measurements for your project. In turn, your mulch supplier can give you a price quote based on your measurements.

B. How to apply mulch?

First, know your purpose for mulching. Are you going to use it primarily for weed control, to cover a pathway, or as infill for a playground or athletic field? Then consider the availability of the mulch in your area. For gardening and landscaping, organic mulches are usually easy to come by, like with leaves, grass clippings, sand, and rocks. If you are using straw for mulching in the winter, layer 4-6 inches to insulate your vegetable garden. Grass clippings can be applied at 3-4 inch layers, but fluff it up when it starts to smell. Fallen leaves have to be shredded so they don’t get blown away; once they’re in the right size, a 2-4 inch layer will suffice for your garden. Rubber mulch still offers the best shock-absorption capacity for playgrounds and athletic fields. Apply at least a six inch layer of rubber mulch and refer to the CPSC playground safety standards for proper application.

C. What to do after applying mulch?

Again, it all depends on the type of mulch and the purpose of mulching. If you’re using organic mulch, you will have to top up, fluff, rake, or replace it altogether in the span of a year. Rubber mulch requires a bit of raking to smoothen but it can last for a decade without needing to be replaced. Mold can grow on coconut husks and shells, so you have to be vigilant about washing them as they can affect your plants’ health. If you’re using straw or hay, make sure they haven’t gone to seed yet so no weeds can germinate on your soil. Grass clippings decompose quickly, so mix some peat moss to slow it down. Sawdust needs constant watering because it absorbs so much moisture. Always be alert for possible fires that can start with flammable mulching material like paper, hay, and rubber.

Whether it’s spring, summer, autumn, or winter, mulching should be part and parcel of your gardening and landscaping activities. Know the best season to schedule your outdoor mulching activities, and learn tips to do them properly.

A. Advantages of seasonal mulching

B. Helpful tips for seasonal mulching

With some imagination and creativity, common mulching materials can go beyond their expected uses.

A. Practical

• Protect packages using shredded rubber mulch. If you have an abundance of rubber nuggets for your gardening project, you can do away with messy packing peanuts and use those instead. The inherent springiness can protect fragile items in boxes.
• Use shredded paper as flooring for chicken boxes/coops. It protects newly-laid eggs and is easier to clean out and turn into compost afterwards.

B. Decorative

• Build an outdoor fire pit using a bag of crushed rocks, sand, and a steel ring to add warmth and charm to your backyard gatherings.
• Have a patch of soil where nothing seems to grow? Go crazy creating ground mosaics using mulching material of different colors and textures. You can design a “pond” using blue, green, and white mulch, for example.
• Select pretty fallen leaves before raking and mulching them in autumn. They can be the center of creative fall projects like garlands, greeting cards, and centerpieces.

C. For Curb Appeal

• Flagstone walkways or paths can add flair to your home. Rubber mulch in particular can add stability to your walking surface because it interlocks like a mat.
• Build curving landscape borders for exterior panache. Rock, wood, and rubber are great choices for garden and landscape edging because they can keep mulch in place for many year

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