I think all gardeners can agree on one thing: mulch is essential! Good mulching practice saves water, naturally controls weeds, enhances soil fertility and plant health, and spiffs up the appearance of a space. Yet everyone has varying opinions on what type of garden mulch they prefer to use. Straw, compost, bark, leaves… there are many different mulch materials to choose from! So, what kind of mulch should I use in my garden, you ask? Well, it depends – on your individual needs, budget, space, aesthetic, type of garden, and what materials are most available to you.
If the concept of mulching is new to you in general, be sure to stop by our Mulch 101 article. It digs deeper into the benefits of mulch, the living soil food web, and best practices of when and how to apply mulch in your garden.
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When it comes to mulch homeowners have a lot of options to consider. Not all mulches are created equal – different types have unique benefits and drawbacks. Understanding the pros and cons of the most common mulch materials can help you make an informed decision for your specific gardening needs.
What is Mulch and Why Use It?
Before diving into the different mulch varieties, let’s quickly go over what mulch is and why it’s an important part of gardening and landscaping.
Mulch refers to any material spread over the top of the soil as a protective groundcover. Both organic mulches (derived from plant materials) and inorganic mulches (like rocks or rubber) can be used.
There are many benefits to mulching:
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Moisture retention – Mulch minimizes evaporation, keeping soils moist longer. This reduces watering needs.
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Weed suppression – By blocking light, mulch prevents weed seeds from germinating and establishing.
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Soil insulation – A buffer between extreme temps, mulch keeps soil cooler in summer and warmer in winter.
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Erosion prevention – Mulch stabilizes soil and provides protection from heavy rains,
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Nutrient addition – As organic mulches decay, they improve soil structure and fertility.
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Visual appeal – Mulch gives beds a tidy, finished look. Colored and decorative mulches can enhance aesthetics.
Now let’s explore the pros and cons of the most popular mulch materials.
Organic Mulch Types
Wood Chips and Shredded Bark
Cedar, cypress, fir, pine, and hardwood bark are common bases for bagged landscape mulches. Different woods offer various colors and textures.
Pros:
- Long-lasting weed suppression
- Natural appearance
- Provides organic matter over time
Cons:
- Can deplete nitrogen as it decomposes
- Needs topping off every 2-3 years
- Can develop mold if too thick
Use for: General landscaping beds, around trees and shrubs
Leaf Mulch
Shredded leaves or partially decayed leaves (leaf mold) make excellent mulch, especially for woodland gardens.
Pros:
- Free and readily available
- Natural look
- Improves soil
Cons:
- Messy and blows around when dry
- May harbor slugs and snails
- Needs annual reapplication
Use for: Flower and veggie gardens
Grass Clippings
If left long, fresh grass clippings quickly mat down into an effective mulch layer. Allow them to dry first.
Pros:
- 100% free source of mulch
- Adds nitrogen as it breaks down
- Readily available from mowing
Cons:
- Can develop foul odor as it decomposes
- May contain weed seeds
- Can clump if wet and thick
Use for: Around vegetables and annuals
Straw
Dry straw makes a lightweight, weed-suppressing groundcover. Wheat and oat straw work well.
Pros:
- Very inexpensive
- Helps retain soil moisture
- Suppresses weeds when thick enough
Cons:
- Can be messy looking
- Risk of contaminants or weed seeds
- Requires annual reapplication
Use for: Pathways, vegetable gardens
Compost Mulch
Screened compost or leaf mold provides an excellent, nutrient-rich mulch option.
Pros:
- Feeds plants as it breaks down further
- Helps build healthy soils
- Available from on-site composting
Cons:
- Limited availability
- May stimulate weed growth
- Needs frequent replenishment
Use for: Annual and perennial flower beds
Pine Needles
Fallen pine needles make a slightly acidic, weed-suppressing mulch.
Pros:
- Helps acidify alkaline soils
- Natural look in pine areas
- Long-lasting weed control
Cons:
- Can be difficult to apply evenly
- Dries out and easily blows around
- Fire hazard in drier climates
Use for: Around acid-loving shrubs and trees
Inorganic Mulch Materials
Gravel and Pebbles
Crushed gravel, river rock, pea stone, and other small stones work well in the right settings.
Pros:
- Extremely durable; lasts for years
- Drought-tolerant and well-draining
- Decorative; wide variety of colors/textures
Cons:
- Expensive, especially for large areas
- Can allow weed growth over time
- Reflects heat; not suitable for all plants
Use for: Pathways, patios, rock gardens, xeriscaping
Rubber Mulch
Shredded tires are recycled into mulch in various colors. Avoid due to potential soil contamination.
Pros:
- Provides a second life for an industrial waste product
Cons:
- Has toxic effects on plants and soil
- Avoid at all costs!
Landscape Fabric
This woven, breathable fabric blocks light to prevent weed emergence while allowing air and water to penetrate.
Pros:
- Effective weed barrier for several years
- Lets water and air reach plant roots
- Available in various grades and strengths
Cons:
- Can be visible as edges deteriorate
- Makes future planting through it difficult
- Not biodegradable; must be removed eventually
Use for: Under ornamental stone mulches
Black Plastic Sheeting
Blocks all light and moisture. Best under gravel or stone mulch. Avoid direct contact with plants.
Pros:
- Totally eliminates weed growth
- Retains heat and moisture in soil
- Inexpensive and easy to install
Cons:
- Impermeable to air and water
- Unsightly if exposed
- Can damage plants if touching stems/leaves
Use for: Vine crop rows, under inorganic mulches
Key Considerations When Selecting Mulch
Choosing the right mulch involves weighing many variables:
- Location – Certain mulches work better in specific settings
- Cost – Inorganic mulches are typically more expensive upfront
- Appearance – Colored mulches for decor; natural mulches for a subtle look
- Texture – Larger pieces for open areas, finer mulches around delicate plants
- Water needs – Gravel may increase irrigation needs; organic mulches reduce watering
- Reapplication rate – Inorganic mulches last longer before topping off
- Soil health – Organic options improve fertility; inorganic don’t provide nutrients
- Weed control – Dense inorganic mulches suppress weeds best long-term
- Environmental impact – Consider sustainability; on-site organic mulches are ideal
By weighing all the variables and analyzing the pros and cons, you can select the ideal mulches to match your unique gardening needs and site conditions. A combination of different mulch types in appropriate areas often gives the best results. With the right mulch choices, you’ll boost your garden’s health, beauty and productivity.
The Disadvantages of Organic Mulch
The disadvantage of leaves as mulch is that if you leave them as whole leaves, they blow around a lot, and once they stop blowing around, they can start to look messy, slimy, and dirty. If you mow over them to chop them up, it takes way more leaves to create a decent mulch layer. You can’t exactly buy more leaves to add to your mulch, although you could volunteer to rake all your neighbor’s yards to collect their leaves. If you don’t have lots of deciduous trees, you’ll have difficulty getting enough leaves to mulch anything.
Straw can be a convenient type of mulch, and it’s often used around things like strawberries to keep the fruits from rotting on the soil. The disadvantage of straw is that it doesn’t look that nice. It looks a bit messy. It’s also not that nice to walk on. And while it does break down and improve the structure of your soil over time, it may also contain the seeds of weeds that grew in the farmers’ field. It also takes a long time to break down, and it can be slippery to walk on when it’s wet.
The disadvantage of grass clippings is that if they’re piled too thickly, they get really hot, which can make the soil underneath them too hot or even potentially start a fire. If they’re spread too thin, they don’t do much to keep the weeds down. When grass clippings dry, they can blow around a lot and are hard to keep tidy, and they don’t look that nice, though they are soft to walk on, and it’s free every time you mow your lawn.
Compost is an excellent mulch type that should look pretty similar to ordinary soil. But, it can be hard to get enough to mulch a large area, and it takes time to create from your own compost pile. Getting enough to mulch your whole garden is challenging. It may not keep weeds down that well since it’s full of great nutrients that plants need to grow.
Wood chips and bark chips are one of the most common mulch options. They’re overall an excellent mulch, but they do have a couple of disadvantages. One being the mold that can grow in and on bark or chip mulch. Slime mold is pretty gross looking, although harmless. Bark and woodchips also take a long time to break down and improve the soil, but in just 2-3 years, they start to look pretty tired and need to be top-dressed.
If you’ve got lots of evergreens, chances are good they’re making their mulch when they drop needles. Getting enough pine needles to make a thick enough layer of mulch to suppress weeds is challenging.
They’ll make enough for the area directly underneath them, but collecting more for other areas of your yard is going to be a slow process. Pine needles can also acidify the soil over time as they break down. It’s not a fast process, but it does happen. Pine needles are also called needles for a reason. So you’ll need to wear thick gloves if you’re attempting to plant under it, and it’s not pleasant to walk on, especially in sandals or barefoot.
Generally, organic mulches are more affordable upfront, and they’re a little easier to apply, but they have to be topped up every few years.
The Disadvantages of Inorganic Mulch
Disadvantages are more specific to certain types of mulch. Here are some of the disadvantages of inorganic mulches.
Rock mulch can absorb and reflect heat from the sun, making an area very hot and dry, so not many plants can survive in the area. Rocks also do not add any nutrients to the soil over time. If a rock mulch layer isn’t thick enough, the weeds will grow right through in no time and can be more challenging to remove. It’s also quite heavy and quite physically demanding to apply.
Plastic sheeting can suffocate the soil, killing not just weeds but also other plants and all the soil’s microorganisms, effectively killing the soil. Plastic sheeting also does not allow water, air, or nutrients to get down to the soil.
High-quality landscape fabric keeps weeds down, but the roots of shrubs and trees will grow through it eventually, making it extremely difficult to remove in the future. Cheap landscape fabric tears easily, breaks down quickly, and only suppresses weeds for a year or two, and then it’s difficult to remove. High-quality landscape fabric is expensive.
Rubber mulch, while produced from recycled materials, doesn’t have much long-term study done on it. There is the risk of rubber releasing chemical compounds into the soil, it also doesn’t break down over time, and it doesn’t improve soil, and it’s also one of the most flammable options.
The main disadvantage of inorganic mulches is the upfront cost: all inorganic mulch types are generally more expensive than organic mulches, but they also don’t have to be top-dressed every 2-3 years.
Which Mulch is the Best for Your Landscape? | Dig In
FAQ
What is the best type of mulch to use?
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YouTube · Garden Project Academyhttps://m.youtube.comWhat is the best mulch to use? How to choose a mulch for low …Jul 21, 2022 — and form a little bit of a water resistant crust arborist chip mulch is an amazing. often free woody mulch material. it’s one of my very favorites a…
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Riverbend Landscapes & Tree Servicehttps://riverbendva.comBest Types of Mulch for Your Landscape [and What to Avoid!]Nov 17, 2020 — What are the best choices for mulch? The best option for mulching your landscape will depend on your preferences, budget, availability, plants, and …
What mulch to avoid?
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Sawdust, wood shavings, and un-aged wood chips:As these materials break down, they consume nitrogen, which is essential for plant growth.
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Rocks and gravel:These can heat up the soil, stress tree roots, compact the soil, and offer no soil health benefits.
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Un-aged or low-quality mulch:This may contain inorganic ingredients, pesticides, or invasive pests that can harm your landscape, according to Lumberjacks, Inc..
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Walnut contains juglone, a substance toxic to many plants, especially nightshades like tomatoes, eggplants, and peppers.
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Plastic mulches:Plastic mulches can break down into microplastics that can be taken up by plants and also contain harmful chemicals.
What is the best thing to use as mulch?
… garden compost, wood chippings, processed conifer bark, leaf mould, well rotted manure, straw (for strawberries), spent hops (poisonous if eaten by dogs) …
What is a major downside to mulching?
They intercept light rainfall from accessing the soil. They have the potential to spread weeds, diseases, and pests.Oct 2, 2020