Science Buddies: "Ask an Expert"

Hello! I am doing a project involving dying rainbow flowers. I searched online for how to dye rainbow roses. The procedure was simple - split the stem of a white rose into four equal quarters and put each part into a different coloured water (using food colouring). I used fresh white roses, chrysanthemums, lilies, and bellflowers, followed the procedure, and let them sit in the coloured water for two days. However, none of the flowers ended up dyed and most of them wilted. I tried again today with a new batch but the roses are already becoming limp. The lily lasted the longest, but did not get dyed either. Also, I used water colour paint (water-soluble) instead of food colouring... Is that a possible reason for the flowers not getting dyed? Would a flower preservative help? Other than that, I can't think of any other reasons why the procedure didn't work - particularly on the rose because it should be the easiest to dye. Please help and suggest some reasons and improvements so I can dye my flowers successfully. My project is due very soon. Thank you.

Hi,

There are a couple of possibilities for why your flowers did not take up dye:

- How much food coloring did you use? The instructions say about 30 drops in 4 oz of water.
- Did you cut the stems UNDER WATER? In order for the plant to take up water the tubes in the stem must be open. If you did not make a fresh cut on the stems the tubes may have sealed up.
- Try doing just a single slanting cut to see if the problem might be the stem splitting.
- Did you use warm water? They say this also helps water uptake.

http://www.proflowers.com/blog/how-florists-dye-flowers
http://chemistry.about.com/od/colorchem ... lowers.htm

Try again and let us know what happened. Cutting a stem into four parts seems to be pretty drastic as far as the plant is concerned. I would think that the flower would wilt if its stem were cut over too long a distance. How long was the cut part and how much of it was exposed to the air? If you could arrange the four solutions so that a maximum of the cut part was in the water and a minimum in air (maybe use four test tubes if you can get them) you might succeed.

Good luck!

Sybee

Hi - I noticed that you said you used water color paint (not the food coloring as directed) - Even though the paint is soluble in water, it might not be a small enough molecule to travel into the stem (xylem) cells. Try again with the food coloring. In the classroom, I have had very good luck using white carnations (they are very hardy); splitting the stem into 2 by making a lengthwise cut up the stem about 1/3 way up and making sure that that entire exposed stem is in the color water solution (use 2 test tubes). I have not tried to cut the stem into 4 sections. It is interesting to see that as time goes by, the color dye ends up concentrated at the edges of the flower petals as water evaporates out of the petal, leaving the dye behind.
Good luck - hope this helps.

The angle at which you cut the stem may also be a factor in color absorption. Sites such as wikihow and about chemistry recommend that you make a slanted cut at the base of the stem underwater, so that the stem does not sit at the bottom of the container. Otherwise, the flat cut would prevent the flower from taking up the dyed water. Also, the cut should be done underwater, because air bubbles that form at the base of stem may block water absorption.