If the thought of having beautifully mulched flower pots, walkways, and gardens with practically no maintenance required interests you, standard mulches are definitely not the way to go.
They will quickly break down, will require frequent replacement, and can become home to a wide variety of unwanted pests.
Glass mulch is an ideal alternative, but purchasing the many pounds needed to cover large areas can be a costly undertaking.
The perfect solution is to make your own glass mulch at a fraction of the cost.
How can you make glass mulch at home? Glass mulch can be made in bulk by tumbling scrap pieces of glass, water, and grit in a concrete mixer for about 10 hours. Much smaller batches can be made in a similar fashion in a rock tumbler. The color of the mulch will depend on the color of the glass used.
Purchased landscape glass typically costs more than $2 per pound, much more if you only purchase small bags.
Why pay so much when you can make it yourself and have fun at the same time?
How to Make Glass Mulch
Small amounts of glass mulch for layering in flower pots can be made in an ordinary rock tumbler.
Sharp, jagged edges will come out smooth, and the glass will have a polished appearance.
Personally, I like the low-noise tumbler by Dan&Darci that I found here on Amazon.
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All you need to do is:
- Add several glass pieces with a thickness of at least ¼ of an inch to a canvas bag, tie the bag closed, and whack it a few times with a hammer until the pieces are about the size of the tip of your pinkie finger.
- Place the pieces into your tumbler, being sure not to overload it, and add water and grit or ceramic pellets (find them here) according to the product’s instruction manual.
- When the tumbler has completed its cycle, empty the contents into a strainer outside and rinse off your new glass mulch.
When you need a large amount of glass mulch, obviously a regular rock tumbler would take way too long.
We’re talking months and months here. A much better alternative is to use a cement mixer.
If you don’t already have one, I would recommend the heavy-duty electric mixer by SUNCOO.
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If this unit is capable of mixing 270 pounds of cement, you know it can handle quite a big load of glass as well.
Many of you would prefer to find a used mixer instead, and that’s fine. Just ask to see it working before money actually changes hands.
Here’s how to make your own glass mulch with a cement mixer.
You’ll see that the basic steps are similar as with the rock tumbler method, just on a much larger scale.
- Have about 8 – 10 gallons of unwanted glass in your desired color ready to go, and chunk them into the mixer. There’s no need to remove labels, tops, rings, etc.
- Add approximately 1 ½ gallons of water and a few tablespoons of rough tumbler grit to the mixer and turn it on. Let it run for about 10 hours.
- Drain the water out of the mixer, add fresh water and let it tumble for a few minutes. Repeat this step several times to help filter out some of the grit and sand from the glass.
- After draining the mixer for the final time, remove your new glass mulch, and place it in a wheelbarrow or several small buckets that you can move easily.
- Make a small wood frame and firmly attach a screen to the bottom.
- Fill a tub with water, insert the frame into the tub, and add a couple of handfuls of glass to the frame. Swish the frame around in the tub to clean the glass. Pick out and discard any trash.
- Repeat for the remaining glass until it all has been cleaned.
- Your new glass mulch will be small, smooth, clean, and ready for use.
The following video will show you the entire process from start to finish (this is how I learned to do it) and might make you chuckle a few times as well.
How Much Mulch Will I Need?
According to Gardening Know How, plan on needing roughly 7 pounds of processed glass mulch for every 1 square foot of coverage at a depth of 1 inch.
You can typically get by with less than that though, especially if you place a weed barrier on the ground before adding the glass.
Where to Find Enough Glass
If you only plan on making enough glass mulch to cover a flower pot or two or a very small area, you can simply use glass from your recycling bin and items such as cracked dishes, broken vases, etc.
For larger projects you’ll obviously need more glass than your recycling bin will provide. Ask your family, friends, and neighbors to start putting aside scrap glass for you.
You’ll definitely want to inquire with your local recycling center about your need for glass. This could be a gold mine for your gathering endeavors.
Also check with local restaurants and bars to see if they would be willing to set aside their empty bottles for you.
Glass replacement companies too will often be more than happy to unload some of their used or broken glass on you if you take the time to ask.
Benefits of Using Glass Mulch
Regular mulch helps with water retention and drainage, keeps soil in place, reduces the presence of annoying weeds, and provides an appealing visual element.
However, glass mulch provides the same benefits and several additional ones as well.
Adds Interest and Color to the Landscape
Ordinary mulches are so commonplace today that they don’t attract much attention or serve as much of a focal point.
On the other hand, glass mulch isn’t very common, reflects light beautifully, and can be made into lovely colors.
It is ideal for creating interesting focal points, highlighting a particular area, and complementing existing garden features.
Blue glass mulch can create the look of a small pond or even a gently flowing stream without the hassle of actually adding a water feature and keeping up with all the associated maintenance.
Similarly, green glass mulch can mimic the appearance of a neatly kept lawn, again without any maintenance required.
You may want to consider making your mulch a color that sharply contrasts the main colors in your flower bed.
Doing so can really make your flowers “pop” when they are in full, glorious bloom.
Lasts a Long Time
Organic mulches need to be replaced or replenished every one or two years, while inorganic mulches, such as rubber mulch, will hold up well for about ten years or so.
Glass mulch, however, will easily last for your entire lifetime and that of your children, grandchildren, and so forth.
Glass mulch will be a permanent covering for the area to which it is applied and will likely not need to be replaced – ever.
Unlike standard mulches, glass mulch won’t rot or grow mold and fungus during particularly wet periods.
These natural processes can attract flies in droves, as flies and other insects are naturally drawn to rotting material.
With glass mulch, these worrisome problems will be a thing of the past because glass doesn’t rot.
Allows for Proper Water Drainage
Glass mulch lets rain water drain evenly into the soil to nourish the plants and prevents puddles from remaining, which could become a breeding ground for mosquitoes and other pests.
While glass mulch is ideal in many situations, there are a few drawbacks that present a problem for some people.
- Glass mulch will last almost forever. Be sure that it’s what you want before adding it to your landscape.
- Once put into place, it is difficult to remove.
- Glass mulch is heavier than regular mulch.
- Edging material may be needed to keep it in place.
- It won’t add beneficial organic material to your soil.
- A barrier of some sort should be used underneath the glass to prevent it from settling down into the soil.
- May be too hot for some tender or shallow-rooted plants.