I am a curious and skeptical individual who often debates with people who believe in planting vegtable gardens by the signs of the zodiac and the phases of the moon. The "believers" always point out that the moon influences the tides of the oceans while I point out I have never observed a tide on Lake Cumberland or a farm pond so the gravitational effects of the moon will have no impact on planting a seed in the ground.
Just what are the gravitational effects of the moon on something as small as a seed?
There are two main ideas behind moon gardening practices. First, lunar gardeners believe the moon's gravitational pull affects the flow of moisture in the soil. Just as the moon has a noticeable effect on the oceans in the tides, the moon may have a subtler effect on smaller bodies of water and thus change the levels of water in the soil. For example, to take advantage of the lunar cycle, a gardener would avoid turning over the soil in his or her garden when there is the most moisture in it (and thus when the soil was hardest to turn over) which lunar gardeners propose is during the new and full moons. Another, less direct, proposed connection between the moon and gardening is that moonlight is thought to have an effect on seed germination because exposure to light can enhance germination.
I could not find any extensive scientific studies conducted to test the proposed benefits of lunar gardening. There was a study done by the Agricultural Research Service in Iowa where they found a link between weed germination and exposure to light. They determined that tilling the soil (i.e. bringing weeds to the surface) was best done at night by a new moon (when there was as little light as possible). Tilling in the dark led to less weed seed germination and thus to fewer weeds in the garden.
More studies definitely need to be done to test the possible connections between the Moon and gardening before I am convinced. However, I would bet that with the extra care and attention lunar gardeners give their gardens, the gardens benefit whether the success is due to the Moon or not.
For more information on the ideas behind lunar gardening check out Caren Catterall's site: www.gardeningbythemoon.com
This page was last updated on July 18, 2015.