Tony O’Neill, gardener and author of the popular “Composting Masterclass” and “Your First Vegetable Garden,” combines lifelong passion and expert knowledge to simplify the art of gardening. His mission? Helping you cultivate a thriving garden. More on Tony O’Neill
I always enjoy spending time in my garden, but sometimes I have a tough choice, such as what kind of mulch I should use in my garden beds. Wood chips, leaf mulch, and even pine needles are options, so I investigated my options and their differences online.
Leaf mulch and wood mulch are different mulches with slightly other uses and properties. While wood mulch takes longer, leaf mulch must often be replaced regularly as it breaks into organic matter.
Mulching is one of the most critical steps you take with your garden, and making the right choice can save you time — and money! Read on to learn more about the benefits and comparisons between both.
Reasons Why Mulching Is Important No Matter What You Choose
When you have amended your soil to make it healthier for your vegetable plants or flowers to grow, you also make it easier for weeds to grow. You’ve cleared out some prime real estate, and seeds blown across the ground can easily take root.
In addition, digging or tilling can unearth weed seeds that were buried and dormant within your soil. What’s a gardener to do? Mulch!
By covering your soil with a layer of mulch, you cut down on the opportunities weeds have to grow.
A layer of mulch spread evenly over the garden and around your plants helps prevent weeds from getting the sunlight they need to grow.
Mulching and its benefits.
Mulching also helps with the temperature regulation of the soil. During the warmer months of spring and summer, it helps keep your plants’ roots cool.
Conversely, during the cooler months, it helps minimize fluctuations in ground temperature and keeps the soil warmer, making it ripe for spring planting and helping to protect your overwintering plants.
When you mulch, you’re also helping lock in a layer of moisture. When you water your plants, ideally with drip irrigation, the mulch around them helps keep the water from evaporating right away, especially in the heat of summer.
That’s incredibly important, especially for plants that crave plenty of water, such as tomatoes.
Wood mulch tends to be the most common type of mulch around. You’ll find several varieties, including wood chips and shredded bark.
Shredded bark can be a hassle because it tends to be filled with splinters that stick into your gloves and clothing, but it can be pretty helpful on a steep slope, where nothing else compares to a material that won’t slip.
Wood mulch and its benefits
Wood mulch is a reliable mulching product. Many people also enjoy the aesthetic of wood mulch: you can find it in colors such as black, brown, and red, and it looks rather neat when spread evenly across the bed.
It is also highly effective at keeping weeds down and helping your soil retain its moisture.
Wood mulch rakes quickly.
As you maintain your garden beds, you’ll also note that wood chip mulch rakes quickly, so you can move it out of the way while planting or tilling. Once you place your wood mulch down, you don’t need to worry about replacing it immediately, so you can kick back and relax, enjoying your beautiful garden more.
Wood also can repel insects.
Using wooden mulch may help repel insects from your plants. The smell of the mulch may be enough to prevent creepy crawlies from making a meal of your prized cucumbers.
Some mulch from specific bark keeps weeds at bay.
You can find different types of shredded bark mulch, but some people swear by eucalyptus bark.
Wood mulch from eucalyptus bark has weed-retardant properties because of its growth-inhibiting characteristics.
This can also work against your plants, so you shouldn’t use it if you plan to have many plants in an area or need them to grow significantly.
Wood mulch disadvantages
It’s also important to remember that while wood mulch has many advantages, it also has some disadvantages.
Limit your tilling on wood mulch.
Unlike leaf mulch, which can be readily tilled into your soil, you don’t want to constantly till hardwood mulch into your soil. If you do, it can pull the nitrogen your plants need into the ground away from the plants as the mulch decomposes.
The pH of the soil may change depending on the type of wood mulch
The type of wood mulch you use will impact your garden and be considered carefully. Mulch from hardwood trees such as hickory and oak lasts significantly longer than softwood trees.
Unfortunately, that convenience comes with a price. Your hardwood mulch tends to be more alkaline, and as it decomposes, it will make the pH of your soil more alkaline, which can affect acid-loving plants.
Wood mulch may crush smaller plants.
Wood mulch is also heavier than leaf mulch.
While it takes more wind to blow wood mulch around than leaf mulch, it could be blown and covered over your plants, potentially even crushing smaller plants.
You’ll also want to make sure you don’t spread the layer of mulch too thick, as your growing plants aren’t likely to be able to push it out of the way.
Leaf mulch tends to come in two primary forms:
- They can come from the leaves of deciduous trees
- or from evergreen pine needles.
Both make an excellent ground cover to reduce weed growth, but what’s the difference?
Benefits of leaf mulch
Because leaf mulch from deciduous leaves also tends to decompose readily, it is great for adding organic material to your soil. Many people compost their leaves as helpful amendments to the garden each year. Remember that insects and snails like living and hanging out in leaf mulch, so you want to keep the mulch from directly abutting your plants.
Leaf mulch is excellent for temperature regulation in winters
In addition, leaf mulch may be superior to wood mulch as a ground cover during winter months to help regulate the temperature of the ground.
Leaf mulch is excellent for retaining moisture.
Leaf mulches will also do a great job of helping retain moisture in your gardens. They tend to be more effective than even wooden mulches, so if you have a hot climate and don’t want to water all the time, consider leaf mulches to give you a helping hand.
Leaf mulch attracts good worms and insects.
Insects and worms love leaf mulch, and the residue mainly attracts worms, which you want to encourage in your garden. As the leaves break down, they provide the worms with nutrition, which aerates the soil and includes worm castings beneficial to your plants.
Leaf mulch is great for vegetable gardens and annual plants
Consider, however, that it may be easier to use leaf mulch in vegetable gardens or gardens with annuals that you intend to replant each year. You can till the leaf mulch right into the ground from the previous year. In contrast, you’ll need to rake away the wood mulch and then reapply it.
Some disadvantages to leaf mulch
It would be best if you also were prepared when using leaf mulch because it can easily be blown away. Shredding the leaf mulch helps keep it on top of your soil but will cause the leaves to break down more readily.
Leaf mulch lasts shorter than wood mulch.
Leaf mulch may not be as attractive as wood mulch: after all, it looks like leaves have just been spread across your garden. Consider shredding the leaves before you use them to help them decompose more readily.
This also has a downside: wood mulch will last much longer than your leaf mulch.
Wooden mulch may last several years, while leaf mulch might not last a year.
Leaf mulch is densely packed to keep weeds out but not so much for the plant’s sprouting.
Leaf mulch tends to become densely packed when you spread a layer across the ground, whereas wood mulch lets in more air and sunlight. This is, however, great for keeping weeds at bay since the leaf mulch covering the sunlight from the soil surface will give weeds a hard time sprouting and growing. This article covered more of what I wrote about leaf mulch against weeds, linked here.
Remember, if your plants aren’t sprouting or growing as nicely as you had hoped.
Leaf mulch from pine needles has less desirable qualities
Pine needles are a less definitive version of leaf mulch. They tend to form an impenetrable layer, which many plants don’t appreciate — although it helps keep the weeds at bay.
Pine needles also tend to be acidifying. They should not be applied around many plants; instead, keep them in areas like your blueberry bushes or azaleas.
Other Kinds of Mulch
There are also synthetic mulches and other options, such as rocks or pebbles. These can be beautiful additions to your garden and often last for years.
There are so many different mulches that can be utilized in the garden. And I cover these in great detail in the video below so you will know which is best for your situation.
Unfortunately, synthetic mulches are much more expensive than wood or leaf mulch and may be more labor-intensive.
After all, moving mulch is often easier than carrying a bag of rocks!
Grass clippings are a rather good option for mulch.
Grass clippings are an excellent — and free — source of mulch. While it’s always best to recycle some of your grass clippings back into your yard to promote healthy lawn growth, you can also spread a layer in your vegetable garden to add some nitrogen to the soil.
You can use your compost for mulching.
Compost is another option for mulching; It can come from organic matter that you have in excess in your home, from plants, food wastes, discarded lawn clippings, and many more. They can be used as fertilizer for your plants and flower beds and enrich your soil. Its many benefits and process are covered in this article that I wrote on composting for beginners, linked here.
But with adding compost as mulch, you might want to add them sparingly. As compost dries out, it tends to become less biologically active, losing its properties as compost.
Instead of just applying compost, why not add a thin layer of compost and then cover it in leaf mulch?
You may also choose stray or hay as inexpensive mulching choices
Straw or hay is another fine and affordable choice for mulching. You want to ensure the hay is seed-free, or you’ll add to your weed problem.
Like with other mulches, don’t pile the straw or hay up against your plants, or you will just be encouraging damage from slugs, snails, insects, and even rodents.
Choosing a Mulch
When picking mulch, it’s essential to realize that there are two main classifications for your mulch: inorganic and organic.
- Inorganic mulch includes black plastic, landscape fabric (yes, those are mulch!), and shredded rubber.
- Organic mulches originate from anything that used to be alive, so wood chips, compost, shredded leaves, and even sheets of newspaper.
Organic mulches decompose, which can improve and enrich the soil as they degrade — even newspaper! They vary in how long they take to break down and how some of their properties, such as pH.
The plants we’ve chosen will collect and cycle Earth’s minerals, water, and air; shade the soil and renew it with leafy mulch; and yield fruits and greens for people and wildlife.Toby Hemenway
In contrast, inorganic mulches don’t decompose or break down appreciably, at least in the short term. They have their advantages, though: while both types of mulches help keep weeds from cropping up, black plastic mulch can warm the soil much more effectively and radiate heat to keep vegetables that like it hot tomatoes or eggplants — much happier.
Considerations When Mulching
When you mulch, it’s essential to consider how you are mulching.
Weed out your garden before mulching.
First, ensure that your mulching area has already been thoroughly weeded. Tossing some shredded leaves or wood chips over weeds that have already taken root is not likely to help you very effectively.
Mulching depth to keep weeds at bay
You also want to make sure that you lay down a thick enough layer to help keep weeds from growing through it, no matter what mulch you use. At the same time, you don’t want the layer of mulch to be too thick, or you can cause your tree or shrub roots to grow up into the mulch or choke down your vegetable plants that are trying to grow.
Typically, a 3 to 4-inch layer of mulch is effective at preventing weed growth.
While some cite using as much as 6 inches of mulch, you can often get away with as little as 2 inches, saving you time and money, particularly in shady locations.
Look into double mulching against weeds.
You might consider a two-pronged approach or a double-mulching technique if your vegetable bed or garden bed is filled with potential weed seeds. After you’ve prepared your garden beds appropriately and mixed in any amendments such as compost, plant your plants.
After you’ve watered them well, put down layers of wet newspaper (it’s okay to wet the newspaper after you’ve put it down but wetting it down first will help keep it from blowing away).
This will break down over the next few weeks but will suppress weed growth effectively. Then layer mulch such as wood chips over it for an aesthetically pleasing look.
‘Mulch volcanoes’ weaken plants.
You don’t want to make a “mulch volcano” around your plants, such as your trees. While this has become a trend, it’s not helpful and can even weaken your plants.
When you pile mulch of any variety right up against the woody stems of your trees and shrubbery, it can cause the outer layer of the plant to weaken and rot.
Water and nutrient transport throughout the tree’s tissue is hampered. In addition, it can encourage rodents and insects to nest around your plants.
Mulching for trees
The easy way to remember how to mulch around trees is the method of “three-three-three.” That means you make a circle of mulch around your tree three inches from the trunk, three inches deep, and roughly three feet in diameter.
Rather than piling the mulch at the base of the plants where it can do damage, make a rain-catching dish around the roots with your tree in the center.
Mulching and How it may affect pets
Mulching too thickly can also build up elements that, over time, can become toxic to your pet.
Certain hardwood mulches may cause manganese to accumulate in the soil around your tree, eventually stunting its growth.
Mulching for flowers and vegetables
Because mulch retains moisture, it can also affect the stems of flowers and vegetables.
Mulching during springtime
Mulches that hold in more moisture also slow how quickly your soil warms during the spring.
This tendency to regulate the soil’s temperature is helpful when you’ve got plants you want to keep warm during the fall and winter, but it can keep your perennials from proliferating.
As a handy tip, pull the mulch away from your plants in the springtime to help facilitate faster growth.
FAQs on Choosing the Best Mulch for Your Garden: Leaf or Wood?
What leaves are not suitable for composting or mulching?
Sure, leaves are less ideal to use in your garden. Leaves from eucalyptus and black walnut trees have compounds that are natural herbicides and can keep the plants you want to sprout from germinating. Leaves with less nitrogen that don’t add to your garden include oak, beech, and holly.
How long does it take mulched leaves to decompose?
It typically takes 6 to 12 months for leaves to completely break down, although adding nitrogen may speed the process. Remember that too many leaves added to your soil may pull nitrogen from your growing plants. You can shorten the process by making your leaf compost pile.
Should I remove leaves before mulching?
You don’t have to, and leaving them can offer you the best of two worlds — using leaf and wood mulch. Be careful not to build up the leaves too thickly, as too dense of a layer of leaf mulch and wood mulch will affect your plants and the weeds you’re trying to prevent.
How long does it take mulched leaves to decompose?
Leaves placed into the compost bin for mulching can take 3 to 6 months to decompose. To hasten this process, chop up the leaves and maybe even look into using a lawnmower for the chopping process. Place them into a compost bin and turn them in every 2 to 3 weeks.
What is the difference between wood mulch and wood chips?
Wood mulch comes directly from trees and nature, while wood chips are usually castings of lumber industries. The former has the advantage of them taking longer to break down. The latter may not be a good choice as they may already have chemical additives from industries that are bad for nature.
Conclusion on leaf mulch vs. wood mulch
At the end of the day, where and on what you will apply the mulch is the deciding factor for which mulch you’ll choose, may it be a leaf or wood mulch. The former can be lighter but denser, but the latter lasts for a longer duration of time in your gardens.
I know we have covered the two types of mulch extensively and some other ones, like compost and grass clippings, as mulch. If you are curious about what you can mulch (spoiler, you can separately mulch sugar cane and rubber!), you can head on to this article I wrote on the best mulch for your garden through this link.
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