Add 1 tsp. of liquid food coloring to 1 cup of water. Drizzle the colored water onto the soil surrounding the base of a plant. Wait 24 hours for the water to absorb. Apply another identical dose if the color change was not sufficient.
The Big List of Free Things to Do With Kids in Arizona. TONS of items on this list--A must read for parents! Lots of items apply to other parts of the country as well. This list has been updated since it was originally published and is now even longer.