Some swear by it, others say there is no proof for it. I speculate its a little of both. Per Maria Thun’s experiments, some plants respond a lot, others not at all, some not as expected! So if you test the principle for a plant you think is water oriented, and test it only in water signs, but it actually responds to fire, you will miss the real result! Science is science. If you are going to test, do it thoroughly for trustworthy results. That said, here is the opinion of a man named Blagrave, an herbalist in 1671! And, yes, even believers disagree, of course! This might make you rethink your lunar premises.
Planting: Plant when the Moon is waxing [increasing, New to Full] and in a water sign: Cancer, Scorpio or Pisces. Use a Lunar Calendar. Avoid the days before and after the new and full moons. New moons produce weak plants, full moons produce quick growing top-heavy plants that fall over. If flowers are important, plant in a waxing [increasing from New to Full] moon in Taurus or Libra, the Venus signs. For root plants, plant in a waning [decreasing from Full to New] moon in an earth sign: Taurus, Virgo, Capricorn. If you want to eat the root (potatoes, carrots, beets, onions, etc.) plant in a waning moon in a water sign, as earthy signs produce woodiness.
Harvesting: For long storage and best preservation, harvest in a waning moon in a fire sign: Aries, Leo, Sagittarius. [Mind you, in 1671, this was important – no fridgies!]
If you get radical, and want more details, check out the Farmers’ Almanac Best Days & Calendars, Gardening Calendar!
Alright! Now you can all be scientists and see for yourself what works! Have fun!