My mother plants seeds in her gardens and asks if planting them when there is a full moon is beneficial or if that is just folklore. Thank you.
The theory is that anything that grows above the ground should be planted while the moon is waxing, or becoming full, and anything that grows beneath the ground (carrots, potatoes, radishes, flowering bulbs) should be planted while the moon is waning as the lighted surface decreases in size until it becomes dark in its New Moon phase.
One explanation is that seeds sown during a waxing moon will come into flower sooner, therefore producing more vegetation, while those sown while the moon is getting smaller will be limited in their reproductive growth, concentrating most of their energy toward root development.
Another thought is that the moon has a pull on the water content of plants somehow affecting their growth.
Then there is the idea that increased insect and pest problems are related to the phases of the moon. If your seeds are germinating during a period of heightened pest activity, you will see a lower yield on your plants.
I cannot personally vouch for gardening by moon phases but I do believe that, when it comes to gardening, if you have a system that works – stick to it.