Backyard Aquaponics
A place to discuss aquaponics

I've see posts on here in the past about people using tumbled broken glass as grow bed media. I did some searches and found some mention of people saying they where going to use it but not any systems where it explicitly said they where using it.


here in central texas i've had a hard time finding gravel without limestone pieces in it. today when i went out to buy a truckload of mulch for out dirt garden i saw that they had 'glass rock' for sale. it's broken bottles and other glass fragments that have been tumbled to take the sharp edges off. experimentally i jabbed my hand into the pile and it came out unscathed... didn't hurt at all. there are glass fines in there that are about the size of large sand... I think I'll screen it to get the fines out.


so i think i'm going to go get a load of it next week and refill my limestone infested growbeds with this stuff unless anyone here would like to caution me out of it. this glass comes from our load waste disposal facility/land fill. some of the glass still has the paint on it like they have on coke bottles. any danger of lead leeching out?

I don't know if there might be anything dangerous about the paint. Personally I'd probably go for it.

One more test you might do before committing. Try plunging your wet hand into wet glass rock just to make sure (be sure to have a clean towel and clear path to first aid in case there are sharp edges.) Remembering that most of the media in a grow bed is wet when you are digging to plant.

another thing i just thought of is light penetrating into the glass medium and algae growth.

Just make sure to get a good think planting going to block light from the media then I guess. Should be better than limestone gravel anyway. Just save some of the limestone to use for buffering as you need it.

booo... well the glass rock is a bust for me.

I screened it and there's a LOT of very small pieces. There's a lot of 'glass sand' and a lot of plastic trash mixed in. plastic bottle label pieces some with adhesive on them. yuck, i don't want to eat out of this stuff. really disappointing because i loved the idea of using a recycled material.

Bummer

We have used recycled glass from our council depot and used it in our hydro system.
We wash it thoroughly first and are careful handling it - also it is very heavy!
Having said that we grew marvellous calabrese and broccolli last year, and this year we have sprouting broccolli and dwarf french beans growing in it.
Another plus for it is it is reasonably cheap to buy and can be reused time after time.
When we flush out our fish tanks the water goes into a reservoir and is circulated through the glass but not back to the fish tanks.

WD