An Enrichment Post: Forcing Paperwhite Bulbs

Today, I find myself in a quandary about what to write. I have a couple of ideas but both stem from irritations, one regarding education and one regarding sportsmanship. I really do not want to ruffle any feathers, which my words would most certainly do if I write what needs to be said. So, I sat for a minute trying to come up with a topic that was interesting but seemed more “neutral.”

Last Thursday, my after school garden club met for its January meeting. The topic was Flower Bulbs. On the surface, I know this seems odd, but when leading a group like this in Wisconsin, we need to find topics we can explore during the winter months. And, there are many, as I have found over the years! But, flower bulbs are fascinating and a favorite unit of mine to teach, having  conducted it probably twelve of the last fourteen years – and that doesn’t count my sessions outside of garden club meetings with individual grade levels or classrooms in our school district.  I did some quick math and figured out that I have provided lessons on flower bulbs to about 545 students and supplied bulbs for another 110 at the high school level.  I have come to know and love bulbs!

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one week of growth, paperwhite bulb 1/10/19-1/17/19

Most bulbs need a cold storage period, or a period of approximately 12 weeks, when they perceive it is winter.  This is why we plant spring-flowering bulbs outside, in the ground, in the fall. During that time, roots grow and take hold, anchoring the bulb in place.  The roots also become ready to perform their “second job” of absorbing water once we have a spring thaw during the longer and warmer days. This gently introduces elementary students to the biological phenomenon of phenology, or cyclic and seasonal change. The bulbs easily demonstrate that the time for growth is triggered by the changes we see in the spring; 1) increased rains and/or thawing of snow, 2) longer days, and 3) warmer temperatures.

The other awe-inspiring piece of information about flower bulbs that I like to share with students is that they contain everything the plant needs to grow for one full year! Everything, including food! Bulbs are modified stems and the modification is that the stems contain food storage tissues or carbohydrates in the form of scales that surround the rudimentary bud other plants structures contained within.  The only additional thing they need are the right conditions – warmth and water! If we provide these conditions to bulbs out of season (such as we are doing now, in the winter), they will start to grow! This is known as the process of forcing bulbs.

Paperwhite bulb parts
Paperwhite botany – © Carol Labuzzetta, 2014

 

The bulbs I have used with success for this unit most often are paperwhite bulbs.  This year, I ordered them over the internet in October. Sometimes, they are hard to find. And, they can be expensive at about $1.00 a bulb.  Otherwise, to do the project associated with this unit, which is planting a paperwhite bulb to take home (and observe) are clear, 16oz. plastic cups, and some perlite or even glass marbles or rocks. No Dirt Needed!!!!! (Remember, the plant does not need a nutrient source for the first year!) Despite that the flower bulbs do begin to photosynthesize and thus, product some food for the plant.

This brings up another detail I point out to the students. The “shoot” or area of growth on the topside of the bulb is often white when first bought or being planted. This is because they have not yet been exposed to sunlight, a necessary component of the chemical reaction of photosynthesis. I urge the students to watch for this color change from white to green!

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Ziva (14-15 size) Paper White Bulb Shoot Prior to Photosynthesis and Basal Plate Prior to Root Development, © Carol Labuzzetta, 2019.

The clear plastic cups aid in being able to observe the changes in the bulb and growing plant structures, something obviously invisible if one just planted the bulb in the ground.  Paperwhites, or  Narcissus papyraceus, belong to the  to the same group of plants as Daffodils. So, if you can imagine a daffodil’s growth, you can imagine that of a paperwhite flower, too. Most school aged children are familiar with daffodils as a spring flower.

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Materials needed to force Paperwhite bulbs in the winter. © Carol Labuzzetta, 2019

We used a pre-measured amount (1 cup) of perlite for the growing medium. This is because it is less expensive and safer than using glass marbles or stones. The perlite also is light enough to allow the roots to exhibit themselves, sometimes, standing the bulb in the air as if it had sprouted pillars or stilts like the shoreline houses found on Pawley’s Island, South Carolina. It always makes me smile to see those “white legs!”

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New root growth, one week after planting. © Carol Labuzzetta, 2019

Once the premeasured perlite is placed in the clear 16 oz. cup, the bulb – basal plate (or the flat hard surface from white the roots grow out) is firmly pushed down into the white growing medium. A little (a very sparingly amount) is added. The cup is placed in a room temperature setting with some exposure to light. Within a week, roots will have sprouted, such as has happened with my examples from last week! A little regular watering, just enough to reach the roots but not surround the bottom of the bulb, and the students will be all set to watch their bulb grow and flower over the next 6-8 weeks!

As I mentioned, this is one of my favorite units for many reasons. Since I am new to this group of students, I look forward to hearing their observations and reactions at our next meeting on February 12th!  Can you tell I’m already looking forward to Spring?!

© All Text and Photographs are copyrighted by Carol Labuzzetta. No Permission to duplicate in any form, digitally or otherwise. Thank you.

2 Thoughts

  1. I love this experiment. I love the metaphor of a bulb having everything it needs packed away inside, and then life just bursting from it when conditions are right. I think I admire the self-containedness of a bulb; that it takes up so little space and does so much with so little.

    Liked by 1 person

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