Most people have seen multicolored carnations in flower shops and grocery stores. There are green carnations for sale on Saint Patrick's Day, for example, and often carnations in school colors when the community high school has a dance. These flowers aren't grown in these colors. Instead, florists perform a small procedure on the carnations in order to dye them to look as if they had grown in these colors.
Put 25 to 30 drops of food coloring in the glass. Add water until the glass is about half full. Stir to mix thoroughly.
Cut the stems of the carnations with a sharp knife. Make the cut at about a 45-degree angle. Immediately place the stems in the colored water.
Place the glass with the cut flowers on a counter or other out-of-the-way place where it won't be disturbed. Check the flowers periodically. You may have to wait 24 hours or more to completely color the carnation, but some color should begin to appear after just a few hours.
Remove the flowers from the colored water when they are the desired color. Rinse the stems in clear water. You may now use the carnations in bouquets or pinned to your clothing as a boutonniere or corsage.