Children's projects Cut flowers

Fun With Flowers: Turn Blooms Rainbow Colors

Dying flower is a fun and easy experiment. Photo: activity-box.com

Here’s a simple summer rainy day project for bored children. Teach them how to dye flowers! 

Then add a bit of a botany lesson at the end.

Gather the Materials

All you need are white or pale-colored flowers fresh from the flower garden, a few tall glasses, water, scissors, a stirring spoon and some food coloring (food coloring is nontoxic to plants).

Among the flowers you could choose from are daisies, cosmos, tulips, chrysanthemums, lilies and roses, but really, almost any flower will work.

They should be white or a pale color, though; dyes won’t show up as well on darker flowers. And avoid fading flowers: fresh flowers just opening are best.

White flowers placed in colored water. Photo: http://www.momtastic.com

Step by Step

  1. Harvest fresh flowers from the garden. 
  2. Strip the flowers of their lower leaves (any that will be underwater). 
  3. Fill the glasses three-quarters full with warm water.
  4. Add about 20 to 30 drops of food color (your choice of color) to the water and stir.
  5. Insert the flower’s stem into the glass, then recut the stem underwater. (Recutting underwater ensures colored water moves into the cut stem, not air bubbles.)
  6. Remove the bit of floating stem.
  7. Repeat with other colors. You can mix food colorings to create your own original hues.
  8. Come back in a few hours to see if there is any difference. Then again yet a few hours later. With some flowers, the full color change can take nearly 24 hours.
White carnations turned pastel shades. They also “drank” a lot of the colored water! Photo: makeitorfixit.com

By the end of the project, you’ll have turned the white flowers to various shades. You can use them to create a lovely bouquet, perhaps a gift for someone’s birthday!

How Does This Work? 

How much you explain to the children will depend on their age … and their scientific bent, but here goes for a rough explanation.

Flowers lose water through transpiration: their open pores allow water to evaporate (disappear into the air). To compensate, they absorb more.

Capillary action moves water up any tube: the narrows the tube is, the higher the water will go. And xylem is really narrow! Ill.: http://www.metalroofing.org.nz

Colored water from the glass will move up the stem through tiny tubes called xylem. It moves up the xylem due to cohesion: water molecules attract each other and move it up the stem, carrying dye to the blooms. This is called capillary action. It’s much like sucking on a straw will pull water from a glass into your mouth, except it’s the evaporation from the flower above that does the pulling. 

The fresh water evaporates from the flower, but the dye doesn’t, leaving the flower color changed.

Will Flowers Also Absorb Dye Through Their Roots?

That’s a question the children might ask you.

This could also be another experiment to try, but it’s more complicated: you’d need potted plants bearing white or pale blooms. Plus, it’s easy for overeager young waterers to drown the plant with repeated doses of colored water. And rotting plants may not be your ultimate goal.

That’s why you might just want to explain the situation to the children rather than demonstrating it.

Here’s what you can say:

Plants won’t absorb food coloring through their roots. Ill.: clipartpanda.com, montage: laidbackgardener.blog

Plants usually absorb water and nutrients through their roots, but roots are also designed to be filters in order to keep out toxins. They act as a defensive barrier and only absorb what plants need in order to grow. That means that little if any coloring (even though it isn’t toxic) will get through and so no color change will occur in the flowers. And all that food coloring would just go to waste!

Larry Hodgson is one of Canada’s best-known garden communicators. After studies at the University of Toronto and Laval University where he obtained his B.A. in modern languages in 1978, he succeeded in combining his language skills with his passion for gardening in a novel career as a garden writer and lecturer. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He is a regular contributor to and horticultural consultant for Fleurs, Plantes, Jardins garden magazine and has written for many other garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening, Rebecca’s Garden and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 50 other titles in English and French. He can be seen in Quebec on French-language television and was notably a regular collaborator for 7 years on the TV shows Fleurs et Jardins and Salut Bonjour Weekend. He is the President of the Garden Writers Association Foundation and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. An avid proponent of garden tourism, he has lead garden tours throughout Canada and to the gardens of over 30 countries over the last 30 years. He presently resides in Quebec City, Quebec.

2 comments on “Fun With Flowers: Turn Blooms Rainbow Colors

  1. Margaret

    Science projects with kids are best!

  2. Most carnations that are grown for the cut flower industry are white, and then dyed as necessary.

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