What is the outer shell of the Redbud Seed?Certain types of seeds, particularly Legumes (and a Redbud is a Legume) have hard outer shells that prevent water from reaching the inner seed, which is necessary for germination. It is a feature on these seeds the has come through evolution. By having this outer shell, the seed won’t germinate late in the fall, or in the middle of summer due to some random rain. This outer-shell will protect the seed from premature germination, that could result in the young tender seedlings death due to frost or summer heat. So, how does nature Scarify seeds? There are several other processes that can scarify a seed – digestion of the seed by an animal that ate it (deer, bird, squirrel). Or, even bacteria/microbes can breakdown the shell over time. Also, freeze/thaw cycles that occur during the Autumn/Winter with a seed in a moist environment can crack the outer shell and prepare it for germination.
A special note on how I stored my seedA note on this experiment. When I gathered my Redbud seed last Autumn, I didn’t store the seed in a sealed container in the refrigerator. I thought that it was OK to just keep them in my basement, which is around 60 degrees F and dry. All seeds were stored together from approximately November until March in these conditions. So, I don’t think this would have had an effect on any particular method being better/worse than the others, since they all received the same treatment. But I do believe that it affected the overall germination rate in a negative way. So, now that I’ve stated that, let me get to the experiment………
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The Scarification Experiment on Redbud SeedsSo, I gathered a large quantity of Redbud Seed last Autumn. This allowed me to be able to try out new methods and document the results. I didn’t get the idea until I had already soaked a large number of my seeds, so that is why the sample sizes are uneven. But in general, I performed four different scarification methods.
- Immersing the seeds in water that had just been boiling, and allowing them to cool/soak for 24 hours
- Soaking seeds in warm tap water for 24 hours
- Rubbing the seed on sandpaper to ‘knick’ or mechanically break the outer coating
- A combination #1 and #3. First by rubbing the seed on sandpaper to break the outer coating, but then immersing them in water that had just been boiling and allowing it to soak for 24 hours
My Seed Scarification Results Table – aka Germination Rate, time to germination, etcI tabulated and summarized my results in the table below.
ConclusionsSo, all in all this was a fun little project / science experiment. Overall I was quite surprised by my results. I fully expected to get the highest number of seeds sprouting / germination rate by the Process 4, sand paper + soaking. I figured that mechanically opening up the outer shell by rubbing it on sandpaper would just allow the water to enter that much quicker. But, I can’t argue with my results. What do you think? Did I damage the seed by first removing part of the shell, then putting it in very hot water? To answer these questions I would probably have to do this experiment several more times in the coming years (and do better at storing my seed!). But, I am pleased with the results. Going back to when I first grew Eastern Redbud from seed I bought, the instructions then told me to soak in boiling water for 24 hours. And, well, I guess that company knew what they were talking about because that seems to be the best method to scarify seeds. And thus, should give you the highest germination rate. Well, I hope you enjoyed this article. Got any questions or suggestions? Ask me in the comments. Also – I made a video describing this whole experiment, and you can have a look at it below. Hope you enjoy! JOIN OUR NEWSLETTER to get our new content sent to you. (No worries, we do not spam your inbox.) Be sure to check out these other articles, I think you would find useful, as well: How to Make DIY Tick Tubes Reasons to NOT Build Raised Bed Gardens Our Simple Method to Compost Our Easy Method to Remove Grass By Hand Native Plant Profiles Find our YOUTUBE CHANNEL HERE: GROWIT BUILDIT YOUTUBE CHANNEL
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