Gardening Science: Investigating Germination





Introduction: Gardening Science: Investigating Germination

The germination of seeds is a perennial* subject in science classes around the world.

Seeds are planted somewhere, they germinate, the students look at them.

The hard part is looking at what you are growing.

The point of this project is to provide students, teachers and interested parents with a starting point for investigating the germination of small seeds, in a way that makes them easy to see and record, using reclaimed hardware.


Step 1: Such a Complicated Set of Equipment...

You need an old "jewel" CD case*, some paper towel or tissue, and some seeds (these are poppy seeds we harvested a couple of years ago).

*You'd be amazed how much science can be done with recycled scrap!

Step 2: Preparation

The CD case has a "liner". You should be able to prise it out with your fingers, but, if your nails are very short, you may need a small blade to get between the inner and outer parts.

Pull out the liner, and discard it and any labels responsibly.  Depending on your local waste disposal services, both should be recyclable. 

Step 3: Growing Medium

You need something to hold the seeds in place.

The easy way to do this is with a pad of tissue paper or paper towel, pressing the seeds against the CD case lid. The amount you need depends on the thickness of your paper - I needed two paper towels, folded into eight, with a little trimmed off the end.

Make sure you put the towel in the end away from the gap left by the liner.

Step 4: Just Add...

...whatever you need.

I dampened the towel with tap water, and laid the poppy seeds in a line, because all I am testing here is whether the seeds will germinate, or be fed to the birds.

Step 5: The Science Bit

What to investigate?

For such simple equipment, there is a lot of good science you can do, as long as you have a number of CD cases.
You could:
  • Investigate the ideal amount of water needed for germination.
  • Investigate the best temperature for germination.
  • Investigate what happens in different lighting conditions (especially after germination) - different amounts, colours and directions).
  • Leave one in your car door pocket to see if vibration affects germination.
  • Dissolve different amounts of fertiliser in the water.
  • Once the seeds germinate, try turning the cases over for different amounts of time to investigate the effect of gravity on plant growth
Because the case is transparent, the seeds are easy to observe during the experiment,  and results can be recorded photographically,  especially if your camera has a macro setting. You can also record important information on the outside of the case with a permanent marker, dry-wipe board marker or a chinagraph pencil.



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    Thanks for sharing kiteman! Some seeds can be very challenging to grow as we are learning! I usually buy organic seeds because you can save them from year to year. I had an experience one year when I planted giant sunflowers, they were beautiful. I saved the seeds to plant the next year and when I did every plant was deformed. I learned something that year! Have a splendorous summer!

    That's not organic vs non-organic, that genetics - a lot of plants sold are first-generation crosses of different plants, which don't breed true.

    Thanks for the reply! OK, I can see how that works. I was under the impression organic seeds were not only organically but were not crosses either. I did a search and learned something thanks to you by the way! I am looking to buy heirloom seeds! They are open-pollinated.

    Any progress?

    Absolutely none.

    See AngryRedhead's comment about damaging seeds - it seems that poppy seeds often lie dormant until the soil is disturbed (hence the poppy fields of WWI). I don't know how to simulate that on damp paper...

    I had some of these growing for a while. They are a tall lavender ordeal that look pretty much like an opium poppy and perhaps is the same species, though they call it breadseed poppy and I heard that they have been bred to have no opiates in them. Once you get one started, you will have them forever as they reseed prodigiously. Never had to disturb the soil as such. A tall shabby flower with short-lived petals that become an interesting round vase of seeds on a talk stalk. Not sure why the spice cabinet seeds don't seem to germinate though, maybe they are treated in some way which prevents it.

    There is a lot of evidence that exposing seeds to smoke generated by burning organic matter greatly increases germination output in many varieties of plants--especially those that naturally occur in environments prone to fire.

    I've read several articles online about this--mostly farming research done by co-ops. Definitely something worth checking out. I'm currently designing a vertical permanent garden structure, so I won't be able to test it myself until next year, I suspect, but I plan on trying it out. You can google "seed germination smoke exposure" for more information about it.

    Really like the jewel case idea!

    If you wanted to make the project slightly more interesting (well, in my opinion at least) and introduce more variables, you could discuss scarification which is a requirement for some seeds. For instance, bluebonnets set seed in the spring and then go through the heat of summer before germinating in the late fall, staying dormant through the winter, and growing rapidly in the spring. The summer heat naturally starts the process, but if you accidentally forgot a bag of seed you collected and didn't get it down soon enough, you could scarify it with acid to mimic what naturally happens. Another example is that some seed need to go through a chilling process before germinating such as Sarracenia (and possibly your poppies depending on the variety), and there are even seeds that are fire activated. The problem with testing some of this is that some seed suppliers scarify the seeds for the consumer, so you'd have to ensure that you got "raw" seed.

    If you wanted to avoid all that and have nice big seed that are easy to germinate and observe, cilantro would be a good choice. I can buy a big bag of unroasted coriander from the Indian grocery store for pretty cheap, and I've had good luck using them as seed - much cheaper than buying packets.

    Cool, thanks for that!