This sounds like an amazing fun little “at home” activity – measuring the growth of a plant. I wonder if you could also measure the root growth? I know that they tend to be windier and far more tangled, but maybe an approximate growth?
I also love the idea given in the post about looking for patterns of growth and comparing different plants. We have windows facing east and west, would that create a difference in growth rates? It would be good for a Biology Plants unit and for STEM.
It should even work for cress in a test tube (that way you don’t have to worry quite so much about remembering to water them!) over a few weeks perhaps.