Ice Cubes"
You all are overthinking Ice Cube use. Ice cubes are only ice cubes when they are 32 Degrees F or below. They are water at any temperature above 32 degrees F. Unless the ice cube is in water, the heated air surrounding the cube rapidly causes it to melt and then achieve the surrounding temperature. A way to test the accuracy of a thermometer is to put it in ice water with cubes in it. If the thermometer doesn't read 32 degrees, the thermometer is not working properly. Put ice cubes in a glass of water. Measure and it should be 32 degrees. Remove the ice cubes leaving just the water. Time how long it takes the 32 degree water (without the ice cubes) to get to room temperature.
Water boils at 212 degrees F. Boiling water should read 212 degrees F.
I'm not suggesting anyone mulch their plants with ice cubes. But judicial use of ice cubes, placed in areas where the cold water isn't dripping on roots should never be a problem.
However, ice made in an ice cube tray with tap water contains dissolved solids and oxygen which can effect the taste and quality of the ice. If you want good ice to water a plant, use bagged ice, or freeze bottled water. There is a difference in the water and the ice cubes.
