As beginning gardeners, we learn that the basic needs of plants are water, light, air, nutrients and a suitable temperature. Different plants vary in the amount of each required for successful growth. Our wish is to succeed in what we do and our natural curiosity encourages looking for ways to make improvements.
Whole philosophies have developed since seeds were first planted by our earliest ancestors based on finding reasons for success and failure. Gardening by the moon is one of these and was known in Babylonian times.
Moon or lunar gardening is based on gravity, the force that attracts one mass to another. Earth, being a large mass, has a gravitational field. The sun and the moon have also, greater or lesser according to their mass. The gravitational pull of the moon causes the sea to rise on the side of the earth nearest the moon. The gravitational pull of the sun, even though it is much further, also has an effect due to its vast mass. Spring tides occur when the moon is full and when it is ‘new’ when the sun and moon are aligned. At this time, the greatest range of tides take place rising highest and falling lowest. The cycle is competed every twenty nine days
What has this to do with plants? There are four phases or quarters of the moon, each lasting about seven days. A waxing moon refers to the first two, between the new and full moons. It is thought to be a good time to graft and plant trees and to sow seeds of plants that grow above the ground because light is increasing. A waning moon occurs during the last two quarters, when moonlight decreases and is the time for slug and weed control, pruning and planting out because root growth is said to be most active. One may have difficulty understanding how moonlight can possibly affect plants.
The moon and sun’s gravitational pull during the new and full moon, causes high tides and is also thought to draw soil water to the surface. Combined with the increase in moonlight, it is said to be a good time for root and leaf growth and the best time for annual crops that produce seed ‘outside’ the fruit, spinach, broccoli, cauliflower and lettuce.
Gravitational pull is less in the second quarter, nearer the full moon, but strong moonlight encourages leaf growth. Two days before full moon is said to be the time for planting crops with seeds ‘inside’ the fruit and grow ‘above the ground’, like peas, beans and tomatoes.
In the third quarter, moonlight is decreasing and the gravitational pull is still high. It is the time for planting root crops, perennials, bulbs and for transplanting seedlings because root growth is thought to be active.
The fourth quarter is a resting period, with less gravitational pull and moonlight, and the time cultivation, harvesting, pruning and mowing.
There are many proponents of these ideas. Research has been carried out by a Dr Kolisko and Maria Thun in Germany and John Jeavons, author of “How to grow more vegetables”. All assert that phases of the moon affect plant growth to a degree and some even go as far believing the signs of the zodiac contribute. However, more objective approaches in more recent years have found that these studies cannot be repeated for one reason or another. In many instances, the results have been anecdotal and research has not taken into account all of the factors contributing to growth.
Experiments carried out by moon gardeners may be subject to “Confirmation Bias”. In that they believe in themselves what they and that their research results confirm it may be due to factors they had not considered. Moon gardeners are committed people and their success may be more due to the care they take and choosing a more suitable time to plant.