Frequently Asked Questions

PRODUCT KNOWLEDGE
The following information gives a basic understanding of what “is” the Growstones™ product.

1.)What are Growstones made from? (Raw Material)
Growstones are made from recycled glass beverage containers received from either the land-fill or another source collecting and processing waste glass. The glass containers are 1st crushed into small glass pieces and then ground into a fine powder (consistent with the size and the feel of flour.) This “glass powder” is the main component in Earthstone (about 99% pf the finished Growstones.) A natural foaming agent is then added to the “glass powder” before it is heated and expanded in the Growstone kilns. To see photos go to Manufacturing Process.

2.) What are the physical characteristics of Growstones?
Growstones are described as: Rigid, porous glass foam media. Growstones consist of glass foam media made from recycled glass containing approximately 95-99% vitreous soda lime glass (inert glass) with 0.5-5.0% of calcium carbonate.
Particle Size:
Hydroponic Particle Size – 1/2" to just less than 1"
Soil Amendment Particle Size – 1/16"-7/16” (>8.0mm to <2.0mm, with the majority of the particles being between 8.0mm and 2.8mm)

The Bulk Density of Growstones is .18 g/cm3.

Growstones have a 35% water holding capacity.

Growstones have a 53% air fill porisity.

Growstones will contain far less fine particles (or dust) than perlite.For more detailed information and to view the Growstones MSDS sheet please go to MSDS.

3.) How does one use Growstones?
This question must be answered in (2) parts, because Growstones can be used in (2) very distinct and different ways. The first and most simple way to use Growstones is as a soil amendment for the cultivation of potted crops, container gardens, flowering beds and/or landscapes. Simply mix Growstones Soil Amendment in to your mix at a 10-30% ratio depending on plant material and climate. See Products Page for specific information or call one of our technical specialists for recommendations.

The second application is for use as a hydroponic growing substrate/media. These three easy steps will allow for easy use in most all hydroponic situations: (1) Rinse by submerging Growstones in a bucket of water (2) Volume of water should be approximately four times the volume of Growstones (3) Discard rinse water in the garden. For detailed directions please go to Labels or call a technical specialist for recommendations.

4.) Has anyone else tested or used Growstones?
Earthstone has invested time and money in testing Growstones. One can visit our Gallery to see images of trials done at commercial greenhouse and universities across the globe.
Research has been done at: The University of Arizona and The University of Wageningen (The Netherlands). Field Trials have been done at: NYC Science Barge, Commercial Greenhouses in Texas, Minnesota, and Florida; as well as by Hobby Hydroponic Stores, Garden Centers and Interiorscapers across the US.

5.) Where are Growstones made?
Growstones are currently manufactured in Santa Fe, New Mexico. As business grows there are plans to open up more manufacturing facilities making it easier for everyone to purchase Growstones.

6.) Are Growstones Organic?
The simple answer to this question is no, Growstones are not organic. The detailed answer to this question are that while Growstones are not organic due to the process of making glass bottles, Growstones can play a vital role in the Green Movement. Growstones can fit into a sustainable agriculture/horticulture program and are definitely part of the foundation of the green movement . . . REDUCE,REUSE,RECYCLE.

8.) How can one purchase Growstones?
To purchase or get a listing of distributors and stores in which to purchase Growstones, please call 469.532.2261.