Mulch, simply put, is an organic ground covering you use to top soil of cover the base of plants. No matter what type of mulch you are using, and yes there are multiple types, the goals are the same. Mulch helps keep moisture in and weeds out which culminates in a lower maintenance garden for you and better environment for you plants.
What Mulch is and Types of Mulch
Mulch can be composed of many different things and each has their own set of pros and cons. Some mulches or purely functional while others can be ornamental. Typically we recommend that you use only functional mulches, as they can look nice depending on where and how you use them. Of the organic mulches that are functional you can use straw, grass clippings, leaves, wood chips, pine needles, cocoa husk, newspaper and cardboard. In each of these there are some deeper details so let’s talk about each before we move on to ornamental mulches.
Straw Mulch
Straw is one of the most common functional organic mulches. It is cheap, light weight, easy to use, and lasts 1-2 months. While straw isn’t just one plant, it’s really the dried stalks of any number of grains, the use as mulch is all the same. Straw mulch can be gotten just about anywhere, but there are some disadvantages to it.
If you get a low quality straw or straw not intended for mulch use it can carry with it hay seed or other weeds that defeat the purpose of mulching in the first place. Overall, this isn’t typically a worry as a good quality straw for mulching is often easy to find, but it is worth avoiding low quality or overly dense scrap straw.
If you already live in a more rural community you might even be able to get straw cheap or free from local farmers who often have more of it than they can use. If you can’t get it for free straw can be found at just about any garden supply store and is very inexpensive.
Grass Clippings as Mulch
If you have a lawn you likely have access to grass clippings. Many people simply toss these straight in the compost as they make a nitrogen rich compost heap, but you can use them as mulch and get the same benefits right in your garden.
The positives to grass clippings are simple. They’re free for starters, but they also make a dense top layer for you mulch than easily strangles out weeds.
The downsides to grass clipping are two fold. First, due to their density, they rot in a rather unappetizing way. The smell from rotting grass can be quite unpleasant though it’s not bad for you garden. The next issue that comes with grass clippings is from when you don’t mow your lawn enough and your grass goes to seed. If you add tall grass clippings to your garden you’re likely also putting grass seed right in your garden beds and grass seeds can grow anywhere. This issue is easily mitigated by mulching only with shorter grass clippings or just by mowing your lawn more regularly.
Wood Chips
Wood chips come in a wide variety when it comes to applications in mulching. Your standard wood chips can come in multiple shapes and sizes from several inch chunks all the way down to saw dust. Rather than break down each type of wood chips we’ll simply state the major things to look for when using wood chips as your mulch of choice.
First and foremost, don’t use recycled wood chips from treated wood as a mulch! The compounds used to treat wood can leach into the soil and be harmful to plants. This is especially pervasive in sawdust or scrap wood chips.
Next, when buying wood chips, be sure to check your labels. Many wood chips designed specifically for mulch have additives for various purposes. Some have anti-flammability treatments added to them, many are dyed, and quite a few have weed treatments added to them. If you use any wood chips with these treatments check the label to ensure they are plant safe before adding them to your garden. Additionally, check if they are vegetable garden safe before adding them to any garden producing food, because some pesticides are fine for plants but not to be used for human consumption. Honestly, labeling laws could be better in the US to prevent the confusion, but for now it’s up to us to double check.
Finally, there are scrap wood chips from untreated natural logging or tree cuttings. These are often the most “organic” friendly type of wood chip you can get, but they also decay the slowest. This is often fine, but it’s important to know that these will take a long time to break down and might not be something you want to till directly into your soil. If you use natural wood chips, often called arborist’s wood chips, also make sure you don’t use walnut, since the wood is poisonous to many plants.
Leaf Mulch
Leaves make an excellent source of mulch and just like grass clippings are often free! Their biggest down sides are that they’re only around for fall crops, and that they need to be shredded before use. The absolute best way to get leaf mulch is to put a collector bag on your lawn more and just run right over that leaf pile!
If you don’t shred your leaves before using them as mulch they can stick together than form a sheet that resists aeration. While this sounds fine on paper, it’s actually bad. Yes it kill weeds more effectively, but it also invited molds to enter your garden and can make a better breeding grown for plant based pathogens. Shredding leaves solves the problem entirely and often makes the leaves easier to work with, so it’s important not to skip this step!
Pine Needle Mulch or Pine Straw
Pine needles naturally form a mulch under pine trees, so why not use it where you don’t have pine trees? While you can get this yourself if you have pine trees it is also readily available for purchase in most garden supply stores. The mulch holds water well and works to tamp down weeds, so pine needles can be a good choice.
On the other hand, pine needles acidify the soil as they decay, so if you’re carefully monitoring your soil pH, then these might not be the right choice for you. While they are a bit easier to work with than wood chips, we find they’re also a bit more difficult to use than straw or other soft mulches.
Cocoa Husk as Mulch
This one is a bit more exotic when it comes to use in most home gardens, but you can certainly get cocoa husks and use them as mulch. While your local garden supply might not stock it, it’s not so uncommon that you won’t find it from time to time.
Realistically, cocoa hulls are not ideal for moist climates or for areas that are open to outdoor pets. Just like chocolate the hulls of cocoa can makes dogs and cats quite sick. The hulls are also super nutrient rich, which can be good for the soil, but if they get too wet they’re so nutrition abundant that bacteria can grow on them too.
In drier climates away from pets cocoa hulls are a good fit as mulch, they’re not only nutrient rich and good for the garden, they also look nice and smell great too!
Newspaper and Cardboard
We’ve seen other site take a light stance on using newspaper and cardboard, but we want to clear the record and let you know that this is a terrible idea. While both can be used a mulch they also contain an enormous amount of chemicals. Newspaper has a lot of inks and paper treating chemicals in it to make it the way it is. Cardboard is one of the most over treated products in the world and can be made in a billion different ways. You never know what’s in cardboard and on top of this it harbors tons of bacteria and molds very easily.
While these do work as mulch, you have no idea what they are adding to your soil. If you do decide to use these, we strongly recommend that you avoid using them for any garden that you are growing edible foods in.
Inorganic and Ornamental Mulches
Next up in our tour of mulch we move onto inorganic and ornamental mulches. We do not recommend these at all, but some people use them in their gardens or simply to prevent anything from growing at all. These include rubber, plastic, pumice, and pea gravel.
Rubber Mulch
There’s not too much to say about rubber mulch other than that it is best used only for landscaping. The mulch is made of a bunch of colored rubber pellets and it acts as a ground cover that holds in moisture and tamps down weeds. Often seen used in more southern parts of the US, if used in any gardens, it usually adorns the base of hearty long lived succulents, cacti, or other year round plants.
Plastic Mulch
Plastic mulch is much like rubber mulch and has similar uses. It’s a decent way to recycle plastic and can be found in two main varieties. Plastic pellets act a lot like rubber mulch, but are terrible for the environment because wherever you put them is where they will stay and they’ll get into your soil. Plastic sheeting on the other hand acts as a fantastic mulch is is the only inorganic mulch we would ever recommend for a vegetable garden. The sheeting is simply laid down with holes cut in it for plants and it holds in moisture and tamps down weeds just like any mulch would do.
The downside to using plastic sheeting as mulch is that it produces waste, looks ugly, and is often not very reusable even in the best of conditions. If you don’t plan properly it can make little lakes on top of the sheeting where water pools. Lastly, it provides no nutrition to the soil, so you’re not going to be able to fertilize through it.
Pumice as Mulch, Not Just for Callouses
Pumice has a huge variety of uses in the garden. It is porous and allows for water and air to travel through it. It’s a natural product, though inorganic, it still is just rocks. It’s also one of the better looking things you can put on a garden. Pumice might also be referred to as lava rocks, because that’s what it is. A natural byproduct of volcano’s!
Like other inorganic mulches it doesn’t provide nutrients to your garden bed, but it is a much better alternative to rubber or plastic for sure!
Pea Gravel
Pea gravel is fine gravel that holds in moisture and creates a dense ground cover that crushes out weeds. We don’t recommend this in a garden however, because it will work its way into the soil and it never breaks down. If you use pea gravel once, you’ll never be able to get rid of it and you’re always going to find it everywhere when you garden in the future. Because of this we only recommend this for landscaping and even then, only where you never plan to garden in the future.
So Much Mulch!
So there you have it! While this is not an exhaustive list of mulch it gives you the best and worst choices laid out plain to see. It’s often a bit difficult to choose your first mulch, but when you’re gardening you’ll have your own set of ideas about what you need, so rather than listening to just any advice, make an informed decision and choose the mulch that’s right for you. Good mulching can help your garden and beautify your homestead, so don’t be afraid to get started.