What’s The Best Mulch For Raised Garden Beds? Mulch 101

Mulch is the ideal security blanket for young vegetables. It insulates soil during winters, protects plants from diseases, helps retain soil moisture, and prevents weed growth. While you can add mulch all around the yard, adding it to your raised beds is especially beneficial. That’s because it means less watering and weeding for you, and better protection for your tender plants.

Unfortunately, there’s no one best mulch. The right one for your raised garden beds depends on what you’re growing. More degradable mulches, such as compost, grass clippings, and straw, ensure healthier long-term plant growth, but less weed control. Wood chips and rubber mulch are also options.

It’s important to note that each plant requires a different type of mulch to grow and thrive. Let’s look at the different types of mulch, the benefits of adding it to raised garden beds, and the best practices you should follow when using it, so you can enjoy higher plant yields in your raised garden beds. 

What Are the Two Types of Mulch, and What Are They Used for?

Raised bed with freshly planted young vegetables and organic mulch in a permaculture garden

From rubber and gravel to grass clippings and sawdust, mulch is simply any material used to cover the soil. It ensures stable soil temperatures, retains soil moisture, prevents weeds, and reduces erosion for healthier roots. 

However, it’s important to note that there are two broad types of mulch, and each serves different purposes:

Organic Mulch

Organic mulch, such as pine needles, compost, and leaves, is something that used to be a living organism. It decomposes fairly quickly, and as it does so, it releases organic material and nutrients directly into the soil, improving its quality and texture. 

This makes organic mulch particularly beneficial for plant growth and root health. So, if you want to fill your raised beds with soil that allows for healthier long-term growth, then organic mulch is the right option for you. 

Inorganic Mulch

Inorganic mulch, such as black plastic, gravel, rubber, and fabrics, is something that was never a living organism, so it either decomposes very slowly or doesn’t decompose at all. 

Inorganic mulches are much more durable than organic ones and are extremely effective weed barriers, which might be just what your plants need. So, if you want to stop weed growth without having to reapply organic mulch every season, then inorganic mulch is the way to go. 

What’s the Best Type of Mulch for Raised Garden Beds?

There’s no one correct answer to this question. In fact, there are many different mulches out there, and the one that best suits your raised garden beds largely depends on what you’re growing and looking for. Let’s take a look at some of the most popular options.


Compost is ideal for raised vegetable gardens because it improves soil structure and quality and keeps roots insulated and safe. This mixture of decomposing material consists of everything from grass clippings to table scraps, making it an extremely nutrient-rich addition to your soil.

The best thing about compost is that you can easily make it yourself.

It’s also important to note that compost is a habitat and food source for beneficial insects and bacteria that break down organic matter, aerate the soil, and release chemicals that help prevent plant diseases. 

If you’re making your own compost, then avoid mixing in bones, meat, tough weeds, animal waste, diseased plants, and any foods with a very high fat content, such as salad dressings, oils, or cheese.

Grass Clippings

One of the biggest advantages of mulching your raised garden beds with grass clippings is that you can easily collect your own clippings. You can either save the clippings after trimming the grasses in your garden or simply pick them up after mowing your lawn.

Make sure you make a four-inch thick layer of clippings around your plants in the raised garden bed. This will create a protective barrier or a woven mat that will help keep weeds at bay. The clippings will also release a lot of nitrogen into the soil, making it much more nutritious for all your plants. 

However, before you mulch your raised beds, make sure the clippings have had enough time to completely dry out. If you’ve collected the clippings yourself, simply spread them out on a tarp, place the tarp under direct sunlight, and let them dry. 


Straw is a great choice for mulching during winter. It retains moisture, prevents frost heaving, and insulates the soil. However, make sure you don’t confuse straw with hay; they’re two completely different things. 

It’s also advisable to purchase your straw from a reputable seller, so you don’t have to worry about your mulch being riddled with weed seeds.

While straw isn’t the most beautiful mulch, it’s cheap and extremely effective at reducing compaction, making it popular among gardeners for both spring and winter applications.

Black Plastic 

Also known as polyethylene films, black plastic landscape tarp (on Amazon) insulates the soil and ensures excellent weed control. You simply need to spread it over the soil one to three weeks before transplanting or planting, and then cut a few holes in it when you start spreading seeds or digging holes.

Heat-loving vegetables, such as tomatoes, okra, melon, and peppers, flourish with black plastic. In fact, studies show that these plants mature earlier and produce higher yields when they’re mulched with black plastic. 

However, the material breaks down quickly after it’s exposed to sunlight. To slow down this process and make the plastic last for several growing seasons, it’s best to bury it under a thick layer of organic mulch, such as pine needles.  

What Are the Benefits of Using Mulch in Raised Beds?

Baby pepper plant in raised garden bed

There are several benefits of using mulch in your raised garden beds, including the following:

  • Mulch helps control weed growth so your plants don’t have to compete for nutrients and water.
  • Mulch helps soil retain moisture to prevent all drought-induced problems.
  • Mulch insulates and warms up the soil to protect plant roots from winter stress and promote early growth during spring. Light-colored mulches keep the soil cool, while dark-colored ones warm it up.
  • Mulch reduces runoff and erosion, so that the soil doesn’t blow away during windstorms or wash away during heavy rains.
  • Mulch prevents soil splash and acts as a barrier, which helps slow down the spread of most soil-borne diseases. Tomatoes, squash, and cucumbers can rot if these soil-borne diseases spread from the soil onto the plant. 

What Are the Best Practices for Using Mulch?

When using mulch in raised beds, it’s important to water the mulch regularly to prevent erosion. If you don’t water your mulch enough, the materials may blow away during windstorms or wash away with rainfall. 

There are several other practices you should employ when using mulch, such as:

  • Spread the mulch at least an inch away from the stems of your plants to avoid fungus and rot problems.
  • Leave at least half of the glass clipping on your lawn, as they’re an essential source of nutrients.
  • If you’re using clippings as mulch, dry them in the sun for a day or two. Don’t use clippings from your lawn if you’ve treated it with toxic pest controls or herbicides.
  • Only use leaves that are at least nine months old. This allows all growth-inhibiting phenols to properly leach out.
  • Use garden staples (on Amazon) to secure plastic mulch over your raised beds. Cover the whole row before planting, and cut out holes for planting as needed.
  • Add a nitrogen-rich fertilizer (on Amazon) to the soil before adding mulch. Organic mulch, particularly wheat straw and leaves, absorbs a lot of nitrogen as it’s decomposing, so a little extra boost will help ensure thriving plants.  

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