October 29th, 2010
Recycled Glass Mulch

recycled glass
Mountain of glass bottles waiting to be crushed and ground into processed glass aggregate (the sandy looking stuff in front.)

Friday Followup

This is one in a series of followup posts. We bloggers often write hopefully about new garden projects; I always want to know, “So how did it turn out?”

Dateline: May 4, 2008

Last Friday Vertie invited me along on her first trip to pick up recycled glass that the City of Austin has made available free to customers who want to use it as decorative mulch, for lining French drains, or to create a drainage layer under a raised bed.

I had seen pelleted glass mulch at the Springs Preserve and on the Travis County Master Gardeners tour and was interested in trying it–especially for free. The City of Austin doesn’t separate the glass by color so what you get is a mosaic of brown, green, and clear glass with the occasional blue shard and a lot of sand mixed in.

recycled glass

When we first saw it, we were both a bit surprised and disappointed. It seemed to be more sand than glass. We were told that over time the larger pieces rise to the top and the sand to the bottom. The photo below is how it looks two months later.

recycled glass

Although the glass has been tumbled in sand, there are still sharp edges. I hesitate to use it anywhere I’d have to weed and dig later (especially since I don’t wear gloves). I think in the future I will use it primarily in places I need to create good drainage.

The decorative glass mulch smells like a stale garbage can. A good rain should wash the scent and sand away.

How long do you think this will stay weed and leaf-free? At least when the revelers walking up from concerts at Auditorium Shores throw their beer bottles in my yard, it will blend in with the landscaping.

recycled glass
2008-07-05. The morning after Fourth of July celebrations at Auditorium Shores.

Followup: October 29, 2010

2008-05-02. I decided to put this batch along the front walk where I tore out the Spanish bayonets last January. I weeded the area and then put down weed blocker cloth before pouring about 3 inches of glass mulch on top. The yard drops sharply at one end and I rearranged the chunks of concrete I recycled when we remodelled our kitchen on the slope.
recycled glass

2009-05-03. A year later. The sand has settled and the large glass pieces risen to the top. I’m happily surprised that it does not collect leaves as much as rock mulch does. Generally it stays much cleaner looking.
recycled glass

2009-12-22. The agave is one of the most beautifully shaped ones in my yard. In the background, some recently-planted opuntia is already getting out of hand and flopping. Bluebonnet seedlings are salad plate sized.
recycled glass

2010-03-21. We had so much rain this fall and winter that the bluebonnets were spectacular. However, the agave was heavily damaged by the massive freeze Austin had in January 2010. It looks terrible and I’m so disappointed.
recycled glass

2010-10-03. The agave has recovered from the freeze damage ten months ago far better than I expected. The opuntia has grown and I’m now struggling to weed around the plants, put weed barrier down, put glass mulch around them. I know it’s much easier to put the weed barrier down first (really!); I just didn’t think the opuntia would be a permanent planting.

recycled glass

To sum up my experience, I like recycled glass mulch a lot. I’m no longer afraid of cutting myself on it. I use it to top off a lot of my potted plants. It has worn well and looks good even after a couple of years–which I can’t say for any other mulch, not even granite sand or decorative rock mulch.

How to Get Glass Mulch in Austin

Note: The location has changed since my original post.

“Color-mixed processed glass aggregate. Generated from the sorting of commingled materials picked up from the City of Austin’s curbside recycling program. Contaminants: Approx. 5%; includes paper and caps.”

1. Check out the website.

The City of Austin has moved the glass mulch from the Burleson Road location to the FM 821 Resource Recovery Center (south of ABIA). The city will load the glass mulch into a pickup for $9.64 per ton (no cash or credit cards, checks only). You can load it yourself for free.

2. If you are self-loading, be prepared.

Vertie and I brought every bucket and plastic container we could load into her car, our own shovels, and gloves. We brought a couple of containers that were almost too large for us to lift out of her car together when they were filled. Wet sand and glass is heavy! Also, we both foolishly wore our gardening Crocs. Wear tough boots! There is lots of large pieces of sharp glass all over the loading area.

3. Check in on arrival.

You will be asked to sign a waiver before entering the landfill.

by M Sinclair Stevens in Austin, Texas

32 Responses to post “Recycled Glass Mulch”

  1. From Frances (Tennessee):

    Your front garden looks perfect with the glass mulch. And beer cans would be such an artful addition. ;-> It probably won’t be long before you will be weeding there, better wear leather? gloves. I do like the look, and wish our city would offer something like that here. Maybe I could make my own, smashing colored glass in a garbage can? Still sharp edges with that method though. Maybe we need to get a glass tumbler? It could work!

    Frances at Faire Garden

    Thanks. I live on a busy street where people let their dogs poop in the plants and encourage their children to pick the flowers. I always joke that rather than planting a “welcoming front yard garden” (as one book described it) mine shouts “keep out”. Shards of glass fit right in with my theme. — mss

  2. From deb:

    What a great idea for recycling glass. Why is Austin always first to “get it” here in Texas.

    You know our motto: Keep Austin Weird! — mss

  3. From Michelle:

    That glass is really cool! What a nifty idea to use that glass for mulch. Now I need to think of a place to use it – like you mentioned, it would need to be some place that requires minimal weeding…

    I’m very interested in seeing how it wears over time. I’ll report back. — mss

  4. From vertie:

    I think you picked the perfect place for your mulch. And I do hope the smell abates a little. My car still smells a bit like a stale brewery, but overall I was pleased.

    Thanks for thinking of me. Any time you want to go again… — mss

  5. From KAT:

    That looks very handsome there, Ms. Msssss.

    Thanks. — mssss

  6. From patientgardener:

    I did laugh at your comment about the revellers rubbish blending in with the landscaping!!!

    Funny in writing but sadly true. They also used to relieve themselves behind the bushes until I planted agave and yucca. — mss

  7. From linda:

    I’m curious to see how the glass will look when the sand settles to the bottom. Even with the sand, it adds a nice textural accent. I like the way you’ve combined a variety of colors and textures with the glass mulch, the stone, the shredded wood, and of course the plants.

    Thanks. Everything is recycled. The glass from the garbage; the concrete from our own kitchen remodeling; the chipped barks from our tree-trimming, and the agave and the yucca plants are passalongs from other Austin gardeners. — mss

  8. From vbdb, austin:

    I agree with Linda’s comment. Your garden has such a wonderful variety of textures and shapes, it encourages me to give in to my adventurous side and try something different. Thanks for sharing the info.

    My pleasure. It was an unintentional side benefit; I just used the materials at hand. — mss

  9. From Mr. McGregor's Daughter:

    It looks great setting off those spiky plants & the rocks. It’s weird that the glass would smell like beer still, don’t they require that you wash out the bottles before putting them out to be recycled or is that just a Northern Illinois thing?

    Do you not have water rationing in Illinois? Maybe they do require it in Austin. I put jam jars and other sticky recyclables through the dishwasher before putting them out. But I’d never rinse out a wine or beer bottle because it would be such a waste of water. — mss

  10. From Lori, Austin Texas:

    Oooh, I really like the way you’ve layered the different textures of the bark mulch, glass mulch, and stone. It’s the perfect foil for xeriscape plants.

    Thanks. It’s not stone, though, it’s piece of concrete that used to be my kitchen counter. They must have made it with granite sand back in the 1940s because it was very hard and it has a slight pink tint to it. — mss

  11. From Mary Lee Coe Fowler (Maine):

    I too put down weedblocker cloth whereever I can. Then I pin it down with anything close to hand: weeds that I’ve just taken out, clippings from cutting down my ornamental grasses, leaf-mold, and – only very occasionally as a splurge – compost or commercial bark-mulch.
    But mostly it’s free materials from the garden itself, like pulled weeds and grass-clippings. I’m now eyeing the contents of our paper-shredder! Not pretty, but cheap and plentiful, and – eventually – biodegradable.

    I wish our cities here in New England would grind up their glass.

    I learned recently in the comments of another blog that weedblocker cloth was controversial. But when laying ornamental glass or gravel as mulch or on paths, it’s a must. It prevents the underlying dirt from working its way up through the mulch. Most of the material I use is recycled or from the garden, too. However, organic material breaks down so quickly here in the humid south that sometimes I have to buy supplemental mulches. — mss

  12. From Bonnie, Austin:

    I’m so happy to see you and Vertie trying it–can’t wait to hear the reviews on it as the sand washes down and more of the glass shows up. Very cool.

    I’ll post more photos over time. — mss

  13. From Lori, Austin TX:

    People encourage their kids to pick the flowers?!! Grrr. I’m so glad my streetside theme is “flower moat.” Lots of rose bushes and agave. ;P

    Yes. They didn’t see me weeding in a nearby bed. I popped up just like Mr. McGregor and said, “There would be more flowers next year if didn’t pick these.” The mother’s excuse…that since they were growing along the sidewalk she didn’t know they were part of anyone’s garden. I’ve gone to the rose bush and agave scheme, too. — mss

  14. From Robin Chotzinoff:

    It may be sharp and scratchy, but it looks magnificent in your yard. I have lusted over the free glass for years. But I’m always seeing swathes of it covered with leaves and general schmutz, and wonder how big a pain it is to rake. Have any of you ever experimented with embedding it in concrete? I know that’s not mulching, but I’ve always thought it would look cool for a path, or even a bunch of stepping stones. But how would it be done right?

    Thanks. Sometime we’ll have to go back to the recycling facility and get some. As for keeping the glass mulch clean, I don’t have much hope for it. I’m already leery of decorative mulch gardens. They look good at first but usually require a lot of maintenance especially around trees and other leafy plants. I believe one can make a kind of making terrazzo out of crushed glass. There are various size of glass sand and chips that can be purchased for this purpose. — mss

  15. From Angelina:

    The first thing I wondered was if there are any sharp bits in it. It looks pretty and seems like such a great way to use recycled glass.

    There seem to be less sharp bits than I thought there would be but all it takes is one. I’m still eyeing it cautiously and wearing gloves when working with it. — mss

  16. From Esther Montgomery - Dorset, England:

    A few years ago, I saw some rather beautiful glass sort of bead things for use instead of gravel on paths. Then, when I came to need some, I couldn’t get hold of any.

    The edges were smooth.

    I wasn’t sure I would have liked it on its own – but mixed in – well, I wish it hadn’t gone off the market!

    Esther
    ESTHER IN THE GARDEN

  17. From Annie in Austin:

    The glass mulch does look good in the streetside garden. I bought a few bags of something similar at Gardenville a couple of years ago when they had a You-Dig section. The mulch seemed pretty smooth and had no smell. We dug it from a big pile for less than $2 for a 5-gallon sack. I used some of the glass to cover the surface of containers and some in a fake river I was fooling around with back then. The first big storm floated most of it into adjoining flower beds.

    Annie at the Transplantable Rose

    The rain has cleaned it up nicely. I’m also thinking of using it in containers. But mostly I want to use it as an underlayer for drainage when I build more raised beds. — mss

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  19. From Amy, Austin:

    How is it holding up a year later? How do you think it would work to use the free glass for depth and buy a few bags of pretty glass to layer on top?

    It’s worked out much better than I expected and much better than granite sand or gravel I have elsewhere. We’ve gone and gotten some more (the location has moved) but I haven’t put it down yet. No, I don’t think it would work to layer a different color glass on top because it will just all get mixed in together. — mss

  20. From Sarah, Austin:

    If you happen to check the comments again… would you mind mentioning where the new location is? None of my old links are working; perhaps the city got rid of the program. I love EnviroGlas but am not ready to head to Plano yet…

    The new location is at the City of Austin Landfill (map) south of ABIA. You can pick up free wood chips as well as free glass mulch from this location. You don’t need an appointment but you will need to check in and sign a waiver upon arrival. — mss

  21. From jeff:

    Has any grass grown up through the glass? I’d like to do this, but I don’t want to pull grass out of it. It looks great, thanks for caring about mother earth.

    I put weed cloth down first so that weeds wouldn’t grow up through the grass. The weed cloth also keeps the dirt and glass separate so that you don’t have to use so much glass to cover the same area. Without the weed cloth it would be harder to maintain, I think. — mss

  22. From Margarette Girgenti, Marble Falls, TX:

    I am looking for some tumbled glass for a flower bed, but I don’t seem to be able to locate any local places to get it, can you help

  23. From Aditya:

    how small is the mulch? Did the larger pieces come to the surface? I have been thinking of getting the glass mulch to xeriscape a large part of my side front yard (about 400 sq ft area) and combine it with native plants. The couple of areas of concern :

    - is smell an issue? I don’t want my neighbors to be unhappy campers
    - is there a long term maintainence needed?
    - does the wind impact the “sand” part of the mulch and blow it ?

    thanks in advance

    The pieces of glass are pretty small, about the size of stones in decomposed granite mulch or slightly larger. The small pieces sink down and the larger pieces come up…like any gravel/sand mulch. The smell is only an issue for a few weeks. It eventually washes out in the rain. I haven’t had any long term maintenance issues. The important prep step is to put weed cloth underneath it. This isn’t so much to keep weeds out (although it does keep weeds from coming up underneath) but to keep it from mixing with the soil beneath and getting all dirty. I’ve seen some people who don’t do this but it looks sloppy. — mss

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  25. From Pam/Digging:

    Thanks for the follow-up! I’m glad to know how it worked out for you. It looks fantastic.

  26. From Ashlee - Austin:

    Thank you for your writing and all the work that you have shared. I am fascinated with glass and using recyclable glass in the yard. I was hoping to email you and ask you a few questions. I am searching for the best tumbler or the best way to make the glass. I enjoy breaking the glass and materials up. Your wisdom would be greatly appreciated.

    I don’t know anything about tumbling glass…it just comes that way from the landfill. — mss

  27. From angelina:

    Austin, as usual, seems to be ahead of everyone else with reuse of tossed materials. I like the way the mulch looks after the sand has sunk to the bottom.

  28. From Elephant's Eye:

    (First time your website has let me in) Recycling is great! But Texas is hot, as we are in summer. Is the glare off the glass not a problem for the plants? Other gardeners have told me to beware of white quartz as pebble mulch.

    I use recycled glass mulch around my xeric heat-tolerant plants like cactus and agave. I don’t notice much glare off it. I don’t think it retains heat as much as gravel mulch does either. Visually, the mostly green and amber glass looks cooler than many rock mulches, especially the pure white (glaring) stone and the pure black (heat-retentive) stone. — mss

  29. From Lynda, Fort Davis, TX:

    Alpine, TX has free recycled glass in clear, brown and green. We live on a ridge in the Davis mountains and get up to 60 mph winds. I use rocks under my roof drip line and fill in with green glass (my yard). I would like to use it in a wider area but am not sure how to secure it from the wind. Any suggestions?

  30. From Chris, S. Austin:

    I am about to use recycled glass to help in zeroscaping the area between the curb and sidewalk. It sounds like I am going to need a permit though.

    Instead of using a cloth weed barrier from a store; lay down a double/ triple ply layer of newspaper and then wet it. It is the ULTIMATE weed barrier. I have an area 6′ by 20′ (pebble covered) and havent had a weed in years.

  31. From Lori:

    Thanks for the glass mulch tips, it helped get me started on a couple projects. I’m in all the way! Am installing it across the entire space between sidewalk and street at 902 W Johanna this weekend and next. We are limited by how much the truck will carry….heavy!! Will be posting my progress periodically at violentcrayon.com

    Looking forward to seeing your new projects this spring.

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