Does Food Coloring Affect a Plant?

Food coloring can affect the color of some flowers.

A common experiment in school science classes is to add food coloring to the water given a plant and see whether it affects the plant in any way. Plants respond to the addition of food coloring differently.

Food Coloring and Carnations

When food coloring is added to the water of cut white flowers, such as carnations or Queen Anne's lace, it travels up the stem of the cut plant through the xylem; hollow cells which run up and down the stem of a plant and serve as the plant's internal circulatory system. The water carried up the xylem carries any food coloring with it and the petals of the flower turn the color of the food coloring.

Food Coloring and Sunflowers

When food coloring is added to the water given to sunflowers planted in soil, only the soil and the stem of the sunflower are affected, with both taking on the color of the dye. Food coloring added to sunflower water may slightly stunt the growth of the plants.

The Safety of Food Coloring and Plants

Because food coloring is non-toxic, it cannot poison plants.

References

• Illinois Department of Physics: Food Coloring and Plants
• Mad Sci Network: Coloring Plant Transpiration
• Planting Science: The Effect of Red Food Coloring on Sunflower Plants