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A foamed glass plant growth support structure, including a foamed glass substrate and a plurality of interconnected pores distributed throughout the substrate. The substrate is characterized by a porosity of at least about 80 percent. The pore size is substantially between about 0.2 and about 5 mill

A foamed glass plant growth support structure, including a foamed glass substrate and a plurality of interconnected pores distributed throughout the substrate. The substrate is characterized by a porosity of at least about 80 percent. The pore size is substantially between about 0.2 and about 5 millimeters and the substrate is sufficiently chemically stable such that water filling the plurality of interconnected pores experiences a pH shift of less than 0.5.

대표청구항 ▼

What is claimed is: 1. A method of making a crushed foamed glass substrate for supporting plant growth, comprising the steps of: a) preparing a mixture of powdered glass, foaming agent, hydrophilic agent, and nutrient material; b) heating the mixture sufficiently above the dilatometric softening po

What is claimed is: 1. A method of making a crushed foamed glass substrate for supporting plant growth, comprising the steps of: a) preparing a mixture of powdered glass, foaming agent, hydrophilic agent, and nutrient material; b) heating the mixture sufficiently above the dilatometric softening point of the glass so that said mixture foams to form a foamed mixture; and c) cooling the foamed mixture to room temperature to form a foamed glass substrate material; wherein said heating step comprises first heating said mixture to a temperature of at or below the dilatometric softening point of the glass, maintaining this temperature for a sufficient period of time to allow said mixture to absorb heat evenly, and then increasing the temperature sufficiently above the dilatometric softening point of the glass to a foaming temperature so that said mixture foams to form a foamed mixture. 2. The method of claim 1 and further comprising the step of: d) before step b), placing the mixture in a shallow mold. 3. The method of claim 1 wherein step c) is a rapid quench to room temperature. 4. The method of claim 1 wherein the mixture further comprises between about 2 and about 8 weight percent foaming agent, about 0.1 weight percent hydrophilic agent, and between about 0.1 and about 2 percent nutrient material with the balance being powdered glass. 5. The method of claim 1 wherein the foaming agent is limestone, magnesite, or a mixture of the two and wherein the hydrophilic agent is ZnO, SrO, BaO, or a mixture thereof. 6. The method of claim 1 wherein the powdered glass is soda-lime-silica glass; wherein the dilatometric softening point of the glass is between about 1250 and about 1450 degrees Fahrenheit; and wherein the foaming temperature is between about 1275 and about 1700 degrees Fahrenheit. 7. The method of claim 1 wherein the foaming temperature is about 250 degrees Fahrenheit above the dilatometric softening point of the glass. 8. A method of making a foamed glass substrate for supporting plant growth, comprising: a) preparing a mixture of glass powder, foaming agent, hydrophilic agent, and plant growth nutrient material; b) heating the mixture to a first temperature of approaching the dilatometric softening point of the glass powder; c) soaking the mixture substantially at the first temperature for a sufficient time for the mixture to achieve a substantially uniform temperature; d) heating the mixture to a second temperature to foam the mixture; and e) cooling the foamed mixture to room temperature to form a solid hydrophilic foamed glass substrate material; wherein the first temperature is at or below the dilatometric softening point of the glass powder; wherein the second temperature is above the dilatometric softening point of the glass powder; wherein the solid hydrophilic foamed glass substrate material is characterized as having a plurality of interconnected pores distributed therethrough; wherein the solid hydrophilic foamed glass substrate material is characterized by a porosity of at least about 60 percent; wherein the pore size is substantially between about 0.5 and about 5 millimeters; and wherein the solid hydrophilic foamed glass substrate material is sufficiently chemically stable such that water filling the plurality of interconnected pores experiences a pH shift of less than 0.5. 9. The method of claim 8 and further comprising: f) at least partially filling the plurality of interconnected pores with water; and g) at least partially infiltrating the plurality of interconnected pores with roots. 10. The method of claim 8 wherein the solid hydrophilic foamed glass substrate material is characterized by a porosity of at least about 80 percent. 11. The method of claim 8 wherein the solid hydrophilic foamed glass substrate material is characterized by a porosity of at least about 90 percent. 12. The method of claim 8 wherein the solid hydrophilic foamed glass substrate material can hold between about 1.5 and about 5 times its own weight in water in the plurality of interconnected pores. 13. The method of claim 8 wherein the solid hydrophilic foamed glass substrate material retains at least about 80 percent of absorbed water for at least about 1 hour in an environment of substantially dry air at a temperature of about 25 degrees Celsius. 14. The method of claim 8 wherein the solid hydrophilic foamed glass substrate material has a density of between about 0.15 and 0.4 grams per cubic centimeter. 15. The method of claim 8 wherein the solid hydrophilic foamed glass substrate material has a density of between about 0.03 and 0.15 grams per cubic centimeter. 16. The method of claim 8 wherein the substrate further comprises between about 2 and about 8 weight percent foaming agent and between about 0.1 and about 2 percent nutrient material with the balance being glass powder.