Using Mulch To Prevent Weeds in Your Garden

Using Mulch To Prevent Weeds in Your Garden

. 6 min read

If you’ve got any kind of a home garden, chances are you can benefit from mulching and using mulch if you’re not already doing so. Lining your garden with a layer of mulch does a number of good things for your garden.

Mulch helps your garden retain moisture by preventing the sun from drying out the soil. It prevents soil erosion. Over time, the mulch breaks down and releases nutrients into the soil. Mulch also prevents weeds from growing in your garden, that last benefit of mulch will be our main the focus here.

Weeds and Gardens

A weed is a plant considered undesirable in a particular situation, the term also refers to a plant that grows aggressively. Weeds are inevitable and unless you’re using strong pesticides or other chemical treatments, you’ve probably dealt with weeds on a constant basis. Routine weeding is one of the more tedious chores in gardening.

There’s no stopping the seeds of weeds from blowing on the wind into your garden, if they aren’t already within the soil to begin with.

What is mulch?

Mulch is “a layer of material applied to the surface of an area of soil. Its purpose is any or all of the following: to conserve moisture; to improve the fertility and health of the soil; to reduce weed growth; and/or to enhance the visual appeal of the area.” (Wikipedia)

Can Mulch Prevent Weeds in Your Garden?

Absolutely! Mulch acts as a deterrent to weeds in two ways. First of all, it provides a barrier against future weed seeds taking root in the soil. A soil might land on the mulch layer, but if its roots can’t make it down into the soil it won’t thrive.

Second, the mulch blocks the rays of the sun, which prevents any weeds seeds already at the soil layer from germinating. Those seeds will lie dormant, as any seed requires indirect exposure to the sun in order to germinate.

So, mulch is doubly effective when it comes to stopping weeds. A layer of mulch properly applied means that your garden will see a dramatic decrease in weeds. That means less competition for the plants you’re growing and less work for you having to dig them out on a regular basis.

But how do you go about laying down mulch in your garden?

Applying Mulch to Your Garden

If you’re growing plants from seed, you won’t put the mulch down immediately. If you plant seeds of fruits, vegetables or flowers and then lay down mulch, you’ll prevent those seeds from germinating. While this is exactly what you want to have happen to weeds seeds, putting down the mulch too early will mean an empty garden.

Wait for your desired plants to sprout and grow higher than the height of the layer of mulch you’ll be spreading. Make sure to give your garden an extra few days for any straggler seeds to germinate. Not all seeds sprout on the same timeline.

During this period of time, you may see some weeds start to grow too. You’ll have to remove those, but once the mulch goes down you’ll see a significant downturn in future weed populations.

If you’re planting already-grown larger plants, you can lay down the mulch as soon as you’ve transplanted and establish those plants into the soil.

A layer of mulch three to four inches deep will prevent most weeds from growing. If the mulch is exceptionally densely packed, you can go as little as one to two inches. Don’t exceed four inches by much, especially if your desired plants are shallow rooted.

You should spread the mulch uniformly so that the entire surface of the garden is covered. While this may seem obvious, some gardeners spread mulch sloppily or unevenly, and then are dismayed to find that they’re still getting weeds in the areas where the mulch didn’t adequately cover.

Once you’ve spread the mulch properly, the mulch doesn’t need much in the way of maintenance. It’s going to be doing its job helping your garden grow better in a number of ways.

Mulch and Watering Your Garden

One important note once you’ve spread mulch in your garden is that you’re going to need to water it less than you were used to.

Mulch keeps the sun from beating down on the soil, which is the primary reason that water evaporates out. A garden without mulch will lose around 80% of its moisture on a sunny day, while a garden with a layer of mulch will lose only 10%.

This is wonderful both from a standpoint of preventing your plants from having their growth stunted by lack of water and because it lowers your water bill and prevents water wastage. But, if you’re already accustomed to certain watering patterns and don’t change your ways, you have a potential problem.

Now that the mulch is keeping far more water in than before, your garden will grow waterlogged if you stick with the same amount of watering. Too much water can be nearly as bad as too little. Plants’ roots can develop mould and begin to rot if constantly submerged in waterlogged soil.

You can avoid all this by simply dialling back on the amount you water your garden after laying down mulch. In fact, you may now find that the natural rainfall sustains your garden, depending on your seasonal precipitation levels.

What Kind of Mulch to Use?

Different types of mulches are best suited for different situations and purposes. For example, wood chips and wooden mulch don’t decompose as quickly as other types of mulch. This makes them great if you’re looking for a more permanent mulch, but the downside is that they don’t break down as quickly and enrich your garden with nutrients. On top of that, wood chips can initially draw out nitrogen from your soil.

Some of the best mulch materials for you garden are organic materials like leaves, grass and hay. One note, though – Never use hay or grass clippings that have been treated with pesticides. This will most likely kill your garden. And if you get hay with seeds attached, you may start to see wheat sprouting in your garden.

A regional option for mulching is pine straw. In areas with many pine trees, this material can be had for free or incredibly cheaply, making it an economical choice. However, you'll only want to use pine straw among plants like tomatoes, garlic, strawberries blueberries and potatoes. And be careful - Pine straw, once dried out, is highly flammable.

Certain non-organic mulches specifically designed for weed prevention are also options. One of the drawbacks of these mulches is that they tend to be rather unattractive to look at. This can be solved by laying them down as a base and then putting an organic mulch on top of them.

In the end, the best type of mulch to use for a garden is likely to be one which breaks down and enriches the soil, like grass, hay or leaves. This saves you money on excessive fertilizer costs over time, and you don’t need to remove a synthetic mulch after your garden has been harvested.

The following infographic gives a great visual guide to the different materials you can use as mulch.

Source: Blog

The Cost of Mulch

Depending on how large your garden is and the cost of mulch in your area, outfitting your garden with a layer of mulch can be expensive. At least, if you’re buying bags of mulch from a home improvement or hardware store.

But don’t let this be a deterrent: It’s possible to get free or heavily mulch from a variety of sources if you actively search for it. With a little bit of resourcefulness, you can supply your garden with mulch without breaking the bank.

One excellent type of mulch is leaves, and you may end up with huge amounts of dead leaves in your yard during fall. Many people rake them up and put them out on the curb to be collected, but this is a waste. When you rake leaves in the fall, set them aside and you’ll be able to use them as mulch come spring.

By that same token, tree removal companies often times end up giving away mulch made either from leaves or shredded wood. To these companies, this is waste they want to get rid of, so you can get it simply by being willing to pick it up.

Municipal governments also end up giving away free mulch for a variety of reasons. These giveaways will usually be posted on a website or notice board. So, keep your eyes open and you may be able to get your hands on free mulch.

The benefits of mulching a garden are many, and you’ll be quite happy with the results if you try it. In addition to all the other positive effects it has on your garden, mulching will largely rid you of the need to constantly weed your garden, erasing one of the annoying hassles of gardening.


Part of the expertEasy team in Melbourne. Mark is a keen gardener, a DIY addict and a father of two beautiful girls. He is originally from Perth and is a true Eagles fan.

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