Cute idea, but there’s no good evidence it matters indoors. The two plausible mechanisms-light and gravity-are basically swamped inside: full moon is 0.1-0.3 lux; your windowsill is hundreds of lux by day and grow lights are 300-1000+ lux. Lunisolar tides do nudge tree stems by micrometers in dendrometer studies, but that’s not a lever you can use for rooting, repotting, or watering outcomes. What does move the needle: timing with active growth, consistent VPD and temp, adequate DLI, clean cuts/hormone use, and media oxygenation.
If you want to test it, do an A/B: randomize cuttings or repots across moon phases, keep all conditions identical, track strike rate and time-to-root, and report back. I’d bet the effect size is indistinguishable from noise.