I am frequently asked, ‘Which kind of mulch is the best for my garden?’
Hands down, I believe that well-made organic mulches are the best for a garden and the environment. After that, there’s a lot of room to consider a variety of amazing mulch options to give a beautiful appearance and provide a personal creative touch to a garden bed.
If you’re still deciding if you should use mulch or are unsure how to use mulch, please check out those earlier blog posts! All organic mulches help with the main reasons to use a mulch; some types of organic mulch are just relatively better for particular uses than others.
Organic vs Inorganic Mulch
Mulch is anything that goes on top of the ground, and there are two broad categories of mulch: organic and inorganic.
Organic mulch is anything that is made from natural materials, such as leaves, grass clippings, straw, bark, compost, or trees and tree branches. An inorganic mulch is anything made from human-made materials, like rubber, plastic, and (in some cases) stone.
I think nature belongs in nature, and unnatural things, like rubber and plastic mulches, generally do not. Inorganic mulches can be appealing—their color can be longer lasting, they don’t have to be changed as frequently, etc.—but they also can hurt gardens and the local environment.
Black rubber mulch, for example, can get hot in our Northern VA summer heat, making the garden’s soil hotter. This can damage plant roots. A mulch, however, is supposed to help protect soil and regulate its temperature—keeping the soil cooler in the hot summer and warmer in the cold winter.
Additionally, rubber and plastic can break down over time, negatively impacting local waterways and wildlife.
I’m going to take dyed mulches off the table here. While I’m them into the inorganic mulch category because the dye usually isn’t ‘organic,’ my primary concern with dyed mulches is that they frequently use wood that can be harmful to the life in a garden. I have a blog post about it here but, as a quick synopsis, the risk/reward just isn’t worth it in my mind.
Saying organic mulches are the best, in some ways, is too general of an answer. But, given the consistent popularity of inorganic mulches (and dyed mulches!), I think it’s an important place to start.
Having organic mulch in a garden helps provide ongoing nutrients to the soil and provides a habitat for earthworms, insects, and other beneficial organisms that help keep a garden healthy and beautiful.
But the mulch also needs to be made well. Of particular importance, the mulch needs to be “cured” over time. This just means that the mulch is brought to a hot temperature and then kept there for a while so that it kills unwanted weed seeds and diseases.
There are a few places around Manassas, VA that don’t cure their mulches (and I’m sure there are many more around NoVA). The companies are typically paid to take old wood (construction debris, trees, etc.) and don’t have a lot of space. Thus, they cut it up into mulch and sell it quickly—they don’t take the time to kill the weed seeds and diseases.
I’ve created a bulk mulch buying guide that can help you find quality mulch.
Each type of (well-made) organic mulch has some relative benefits that make it especially good for certain uses. Here are some of the things that I think about when deciding what types of mulch I use in my gardens.
Mixed wood mulch and shredded hardwood mulch
This is also called “shredded hardwood” mulch and I think this is the most typical ‘organic mulch.’ I use this in most of my gardens at our composting facility in Manassas, VA.
I like that its slightly coarser size is great at helping prevent soil compaction, like walking to get the hose, or cutting through the garden at work since it’s sometimes faster than walking around it. While walking across my garden isn’t great for its soil, I’d rather design and protect my garden from use (rather than pretend I don’t do this!). I also love that this is a natural-looking mulch for my native plant beds.
There is a distinction between hard and soft wood. However, the companies I am familiar with in Northern Virginia only sell mixed wood mulches but are sold as “shredded hardwood mulch.” Indeed, some companies use 50% of an ingredient as a guide. For example, a “hardwood mulch” might be 50% hardwood and 50% softwood; a “cedar mulch” may only be 50% (sometimes less!) of actual cedar wood.
Our double-shredded mulch is about 50% hardwood and 50% softwood. It comes from fallen or cut branches in the area so there is no construction debris. This lets us return the natural things from NoVA back to our local environment (almost like what is done in nature).
As mentioned above, finding a good source for this mulch is important. Because so many people buy this mulch and it’s easiest to make, a lot of companies make and sell double shredded (hardwood) mulch. Just avoid the companies that don’t monitor the temperature of their mulch and let the mulch sit for about 60 or more days.
Personally, this is my favorite right now—I love the look of leaf mulch. It’s light like straw mulch but is probably the easiest of the mulches to spread. It’s got a beautiful dark color and, because the size of the individual pieces is smaller than most other mulches, it creates a very smooth texture on top of a garden bed. I also think that this mulch stays darker than some other mulches throughout the season.
A leaf mulch does break down relatively quickly so it will need to be replaced or topped off two times a year (I think this is a best practice anyway). For some, this is a drawback, but I particularly like this since it helps make my soil healthier. This is my earlier blog post that introduces our leaf mulch.
I wouldn’t use a leaf mulch where there may be weight applied to it, like a walkway or around trees where a mower tire or blade will consistently be right next it (or on) it. With the finer particle size of the mulch pieces, it compacts more easily and doesn’t give the same compaction protection that a double shredded mulch provides.
I use leaf mulch in front of my house (in the DMV area), where I like having a particularly “clean” look for my garden. We have great leaf mulch that we sell in the first part of the year while our supplies last. It’s also really easy to make your own at home by running the leaves that fall in your yard through a leaf sucker or mower. Those fresh leaves won’t have the same dark color but are free and great for use in the fall/winter!
These are made from the bark of trees such as pine or cedar and are particularly sought after for ornamental gardening because they can sometimes help encourage a particular soil pH that’s particularly important to this type of garden/plant.
Overall, bark mulches don’t break down as quickly as other types of much and are very good at protecting soil compaction.
They are particularly expensive, however, so are most frequently only used with ornamental gardening, where promoting a particular soil pH is helpful and the cost of the plant is high (so an expensive mulch tailored to the tree, shrub, or plant makes sense).
I’ve noticed over the years that good cedar mulches are harder to get and many companies are mixing cedar bark with other types of bark. It’s important to ask the mulch maker or seller what percentage of the bark mulch is the particular type of tree that you’re looking to buy. I believe Norfleet Quality Mulch does a particularly good job with their cedar mulch (there may be one or two others as well).
Made from the stems of cereal crops, like wheat, oats, and barley, straw mulches can be a good choice for a garden.
I think it’s particularly good in vegetable gardens because they break down quickly (adding nutrients and organic matter to the soil). Additionally, the lighter color of the straw helps reflect the sun during our hot DMV summers, keeping the soil cooler.
If you’re buying a straw mulch, make sure that it’s been made correctly. The biggest risk in using this is that they still contain the seeds from the crop that can then germinate and grow in your garden.
I would avoid using straw mulch wherever you may have traffic on your soil because it doesn’t help protect a soil against compaction that well. Thus, I would not use it for the rows of a veggie garden, where I walk to get to my hose, etc.
Who doesn’t love free?!? While I haven’t seen a company selling grass mulch, it’s great for a garden and can be made right at home. After mowing your lawn, collect the grass clippings, spread them out on a driveway to dry, and then put them in your garden.
I haven’t used grass mulch personally because I put grass into my compost. I like to have the nitrogen from the grass for the composting process to help break everything down into beautiful, dark compost.
I recommend using grass like a straw mulch (above) since it’s got so many of the same characteristics.
A lot of people swear by using compost as mulch. This is spreading about 2 inches of compost over the top of the soil. As a composting facility that sells bulk and bagged compost, I would make more money if everyone did this, but…
I think there is an important distinction to make here.
As I recommend in my tips for getting a garden ready for spring and winter, I like spreading a thin layer of fine compost—‘topdressing’ the soil with about ½’’ of compost—and then putting a mulch over it. This gives me the best of both worlds—the nutrients and microorganisms that are in the compost as well as the protective properties of mulch.
If you’re only looking to lay down one product (instead of two) and want to use compost mulch, I suggest using a very coarse compost so that you get sufficient soil protection (but even this has a risk of having too many fine particles in it).
If the compost is too fine of a material, it will be too much like great soil and not enough of a mulch. In fact, I’m planning to plant my veggie garden this year directly into pure compost!
We make a nutrient blend mulch that is a mix of our double shredded mulch and our certified compost that tries to replicate what I recommended doing (but I still prefer the two-step process).
This mulch is a particularly good option if you’d like to save some time or have limited space when buying products. It’s hard to fit bulk mulch and bulk compost at the same time in the bed of a truck. Thus, the options are buying: the nutrient blend mulch, bulk mulch with bagged compost, or taking separate trips for bulk compost and then bulk mulch.
If you’re going to buy coarse compost on the market, please look at my compost buying guide because coarser compost can sometimes be a warning sign that the compost isn’t made well (instead of being a “compost mulch”).
I think that’s a great initial list of mulch options to choose from. Whatever you end up choosing, organic mulch will be an easy win-win for your garden and our local community.
If you have a favorite mulch, please let us know about it below
Freestate Farms makes premium landscaping products—compost, topsoil, and mulch—by recycling food and yard waste in Manassas, VA. Our composts, topsoil, and mulches are specially designed to increase the health and productivity of local soils, and with our focus on sustainable practices, this lets the environment and your garden Grow Good, together. We sell bulk compost, bagged compost, bulk natural mulches, bulk dyed mulches, bagged dyed mulches, and bulk topsoil.