Has anyone ever heard of this folklore?
It has something to do about the time to plant peas.
For planting by the moon, which was thought to have the power to draw things out of the earth: "Sow seed when the moon is waxing (growing larger). Sow root crops when the moon is waning."
For planting peas: "Plant peas on St. Patrick's Day for the blessing of the saint himself on your entire garden."