Does the Dioscorea caudex grow faster underground

I have read this many places online and did a small test using 4 seeds of Dioscorea Elephantis. After 4 months there was a clear difference between the underground and above ground seeds with the buried caudex being larger and much lighter in color.

To better test this assertion that I have read on many webpages I am germinated 24 seeds of Dioscoreaceae Meixcana. I have not sorted out the complete plan but once I know how many germinate I will attempt to grow 4 to a 4" pot and randomize two per pot to being covered completely v. 50%. I will then follow caudex width, length, estimated volume as well as number of leaves and survival every 6 months. I don't believe I have all the info I need to do formal power calculations but I am certain that this number could detect the effect if it is as impressive as my experience with D. elephantis. If no effect is appreciated in this size that would be more then enough info to guide the treatment of these plants by fellow amatures. Suggestions?

The effects of light on root growth in mint. a pseudoscientific effort.

I am starting with six. cuttings of spearmint all from the same plant. I cut them to the same number of leaves and removed the bottom two sets of leaves. I then put them in two jars full of tap water. I then covered one with a opaque plastic bag. Hopefully these two sets are similar enough that we can see a difference if there is one in the growth of roots with and without light. One concern I have is a difference in temp caused but the bag. oh well I can think of no real simple way to control for that.


This needs tested because I have been making wine bottle hydroponics for mint that are clear. wine bottle hydroponic mint
For other mint thoughts check out: Making a good mojito.

Preliminary results DAY 3:
roots are sprouting in 5 of the six available spots on the roots in the light and 2 of the six spots on the roots in the dark. Surprising to me. was it heat? does light stimulate root growth. can anyone propose a better experiment to sort this out?

FINAL RESULTS day 14: no difference. the two are indistinguishable