Is there any truth behind planting by phases of the moon?

Question

A book I've been skimming through recently, How to Grow More Vegetables and Fruits, talks about this, and I've also heard it mentioned, and read about it several other places--perhaps most notably the Farmer's Almanac which I have seen for sale on many news stands, and which has a web site.

From the book:

One of the most controversial aspects of [our] method is [the] method of planting seeds and transplanting seedlings according to the phases of the moon.

... Short-germinating and extra-long-germinating seeds are planted 2 days before the new moon, when significant magnetic forces occur, and up to 7 days after the new moon. Long-germinating seeds are planted at the full moon and up to 7 days afterward. Seedlings are transplanted at the opposite time.

(emphasis in original)

It goes on to explain in much greater detail when certain types of seeds and seedlings ought to be planted or transplanted, in accordance with lunar phases.

The gist of it seems to boil down to the idea that moonlight helps leaf development, and that lunar gravity, helps root development. (I'm not really sure what it means by the "magnetic forces" in the above quote).

At least the book acknowledges, right off the bat, that this lunar stuff is controversial. But my question is: Is there real evidence that there is a benefit to plants to be planted and/or transplanted by phases of the moon?

Answer 1

It is local lore in Costa Rica too - but reality is their stuff grows any time of the month!

The "magnetic forces" bit really is BS. The Moon does have a small relict magnetic field but you have to be on the Moon or low lunar orbit with specialist equipment to detect it.

It pales into insignificance when you compare it to the Earth's (very active) field, and the solar magnetic field. Even locally magnetized rocks are going to have more influence, and even these will be drowned out with the fluctuations from the Earth/Sun interaction - which can be over times scales of seconds to 11 years.

The lore might come from countries with strong seasons (eg. the UK and not Costa Rica) where planting in a specific 1-2 week window really is ideal. However it isn't the phase of the Moon that is causing this, but the actual seasons. If you don't have a calendar , then you would naturally use the Moon. From this some Moons even have names - e.g. the Harvest Moon is traditionally when grains are harvested. It marks the right time of the year (to an accuracy of about 2 weeks) and gives good illumination past dusk. I would imagine the same would occur for planting - "Well son, you need the first half Moon after the start of Lent" or something like that. Earlier and it might be too cold; later and the crops might not have time to mature.

Answer 2

How to Grow More Vegetables editions 1-4 state that the ideas are based on the "biodynamic/French intensive method", the most recent edition of the book calls it the "Chinese Biointensive way of farming" although the content is the same. There are parts of that book which are useful and parts of that book which are plain BS. Some of the biodynamic suggestions are good. The planting by the phases of the moon stuff as presented in this book would fall under biodynamic theory. Biodynamic farming in general is much a pseudoscience (see wikipedia entry) However, planting by the phases of the moon may have merit, more scientific research is warranted before it can be recommended.