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Thursday, March 3, 2022

Science Idea for young gardeners - beans sprouting by Vicky Spelman




Do you have some old CD cases around?  They are perfect for a science experiment to show beans sprouting with some potting soil.   No CDs around – use a glass jar, and some cotton balls or crinkled up paper towels.  Beans are easy to sprout and will benefit from presoaking for several hours – or overnight (up to around 12 hours).

Germination is the growth of a plant contained within a seed; it results in the formation of the seedling.  When seeds sense that there is enough water to grow, and that the temperature is right, they will germinate.  The bean seed will lay dormant for around 7-10 days, then a root will appear that allows the plant to have more water access. 

After removing the CD inserts, open on a flat surface with the inside part facing you.  Add some premoistened potting soil (a handful - damp to the touch) to the bottom of the CD case and place 2-3 beans in the soil (spacing evenly).  Secure closed CD case with a rubber band and place in an area that has dark and warm conditions.  Most seeds germinate best under dark conditions like when planted in the garden soil.  Check your soil periodically - if it looks dry, open case and spritz some water to dampen it.  

If using a glass jar and cotton balls, squeeze out the excess water and place bean seeds between the jar insides and the cotton balls.

Photo: Vicky Spelman

Early seedling development – beans are an example of Dicots (two-seed leaves).  The primary root, called the radicle, is the first thing to emerge from the seed and anchors the plant to the ground to allow it to start absorbing water.  Next the shoot emerges from the seed. 

In dicots, the shoot has three main parts:  the seed leaves (cotyledons), the section of the shoot below the seed leaves (hypocotyl), and the section of shoot above the seed leaves (epicotyl). 
Steps of Seed Germination - Penn State Extension

After the shoot emerges, the seedling grows slowly as it uses the stored energy of the seed.  True leaves that look like the leaves of the mature plant will appear.  These leaves, unlike the seed leaves (cotyledons), photosynthesize light into energy, allowing the plant to grow and develop.   You will want to make sure your plant gets enough sunlight now. 

Additional Information:  Seedling