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An introduction to gardening by the moon Featured

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Gardening by the moon is very popular in France, and many "jardiniers" align their activities to the cycles of the moon. Is there any sound basis to this, or is it simply folklore ? This article explores lunar gardening and examines possible links between the moon and the plants in our gardens.


If you live in France, and share an interest in gardening, then you will probably have come across the idea of gardening by the moon. This doesn't mean buying a ride-on mower with headlights, or escaping into the potting shed on winter evenings during “Strictly Come Dancing”. It's the belief that plants respond to the position and apparent size of the moon. Thus, some days are better than others for planting, tending and harvesting your crops and flowers.

Around the end of the year, most French gardening magazines are offering lunar calenders for the coming year, and bookshops offer books devoted to the subject. Since the passage of the moon is different every year and predictable, the devotee needs to use the current year's calender. Thus some of the impetus for lunar gardening could cynically be considered to be commercial. However, that is only in recent times, and there is a wealth of evidence that many ancient societies, ranging from the Celts in early Britain to the Maoris in New Zealand have practiced lunar gardening. Pliny the Elder (AD 23-79), the Roman historian, in his Natural History gives instruction on how to regulate agricultural activities according to the cycles of the Moon.

If you've gardened in France for some time, chances are that friendly neighbours have already proffered advice as to when is the best time to sow, transplant and harvest. They may claim that following the moon increases germination rates, improves the yields of vegetables, or allows gardening without irrigation. It's a subject that most French gardeners have an opinion about, and many have experience of. The fact that it's been practiced over the centuries is often cited as proof that it works, but there have been few decent scientific studies supporting lunar gardening. To make the issue even more confusing, the plethora of lunar gardening calenders available do not all agree on what to do on specific days.


cherry moonLet's take a look at the moon – it's visible most nights but surprisingly few people take note of the phase of the moon. The moon has four basic states - New, Waxing, Full & Waning. When the sun and moon are on opposite sides of the earth, the moon appears "full" to us, a bright, round disk. When the moon is between the earth and the sun, it appears dark, a "new" moon. In between, the moon's illuminated surface appears to grow (wax) to full, then decreases (wanes) to the next new moon. This cycle is known as a “lunar month”.

The most common advice is to sow on a waxing moon and harvest on a waning moon. Another common rule-of-thumb is that it's never wise to plant on the day of the New Moon or Full Moon. Let's have a look at how the moon might influence the growth and fortunes of plants.


Most theories start with the premise that the orbit of the moon affects sea tides on earth. This is said to be due to the gravitational pull of the moon on the vast volumes of water that make up our oceans. Following on then the pull of the moon is also thought to affect the water table, that is the level of water beneath the soil. That clearly would have an impact on plants, possibly more in summer when the water table is lower. It is thought that moisture int the soil is at its highest when the moon is waxing, and falls with a waning moon. Thus, planting would be more successful during a the first quarter when the moon is waxing, or moving towards a full moon. The waning moon from full to last quarter is when the moisture content is at its lowest and there’s less sap rising in trees and shrubs so it’s when you should do your pruning.

In addition to the moon's effects on oceans and the water table, some say that the gravitational pull also affects the water content of living things – plants, animals and people. If this is true again that would affect the growth of plants, but most likely it is too minute to be measurable.


As well as the position of the moon determining the gravitational pull, it also changes the brightness of the moon. The moon shines by reflecting sunlight, though not very well. It reflects only about 7% of the light that strikes it, which is comparable to a lump of coal. However, that's enough to see by with a full moon. Some supporters of lunar gardening suggest that light from the moon encourages leaf growth, and conversely darkness promotes root development. Thus it is advisable to plant crops that produce above the ground on a waxing moon (moonlight increasing) and to plant crops that produce below ground during the waning of the moon (moonlight decreasing). This is the source of the old adage, “plant potatoes during the dark of the moon.”

Another connection between moonlight and plants is thought to have an effect on seed germination because exposure to light can enhance germination. In a study done by the Agricultural Research Service of Iowa, they found a link between weed germination and exposure to light. They determined that tilling the soil (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.

Moonlight might also affect the fortunes of seeds and plants since it changes the habits of predatory animals, birds and insects. Mice, for example, are known thieves of newly sown peas. On a bright moonlit night, their predators could find it easier to spot their prey. Fewer mice – more peas !

Actually the path of the moon around the earth is elliptical. When the moon is at its closest to the earth, known as the “perigee” the amount of reflected light has been shown to be 30% more that when the moon is at its most distant, called the apogee. Thus any effects attributable to moonlight could be expected to be stronger at the perigee and weaker at the apogee. French gardening calenders tend to recommend doing no gardening at all on these days, for reasons that are not entirely clear. Additionally they recommend no gardening also on the days of lunar nodes – that is the half-way points between perigee and apogee. Maybe such calenders are devised by gardeners who feel that 25 days gardening per (lunar) month is quite enough and it's nice to have an excuse to take four days off !


So far, so good. We have seen that there could be good reasons for following the position of the moon, or lunar calender, to plan garden activities. The lunar month is approximately 29.5 days, and the phases of the moon have been calculated with absolute accuracy into the distant future. Many lunar gardeners simply follow this so-called synodic cycle, which has an intuitive nature and the “rules” are easy to remember. Just take a look at the moon each evening, and it's pretty clear in which phase you are. If the moon is new or a full moon it's obvious, and if the moon has a crescent shape there's a little trick to decide the quarter. Imagining a vertical line against the crescent, if it forms a “p” shape then you are in the premier quartier (waxing moon), and if it forms a “d” shape then it's the dernier quartier (note that this aide mémoire only works in French!).

Most lunar gardening calenders however take the art (or science ?) to the next level of complexity. This more detailed refinement uses the twelve Zodiac signs as a method of positioning the moon. This method was developed by Rudolf Steiner in 1928, and the Zodiac signs used were the actual positioning of the signs in the sky, when the moon passed through them. This is where the degree of specificity to certain plants becomes less believable in my opinion. Astrology attempts to assign a similar importance to the positioning of stars and constellations at the moment of a person's birth.

moon treesThe passage of the moon in front of the constellations is claimed to act as a 'lens' that emphasizes the effects of the moon phase and moon path on different parts of the plant. The moon travels through each one of the Zodiac signs about once a month, staying in one constellation for about two and a half days before moving on to the next one. Thus zodiacal planting guides not only recommend days for certain activities, but the time of day can also be important.

The Zodiacal approach recognizes four kinds of days - Root Days, Flower Days, Leaf Days, and Fruit Days. Some link these to the four elements Earth, Air, Water and Fire (respectively) with a connection that's a little tenuous. The four elements are traditionally linked to the twelve constellations, thus providing each day with an advice to focus upon roots, flowers, leaves or fruit. For example, if the lunar gardening guide indicates a Flower day then it's a good time to plant bulbs, take cuttings or harvest flowers for drying. On a Root day you should sow radish, and on a Leaf day you can cut the grass or prick-out lettuce seedlings. On Fruit days it's time to harvest crops. In addition, don't forget those four days each month when the advice is to do nothing ! French lunar gardening calenders are mostly based on this approach, and often provide additional recommendations and exceptions. If you garden in France, it's better not to use an English or worse American guide, since the timings of the moon's position are of course a little different. Consulting a “Jardiner avec la lune” calender daily is a great way of improving your French, and you'll have something to discuss with neighbours !


The concept of gardening by the moon has been practiced for centuries throughout many cultures of the world. Like many things that are not fully understood, it has attracted believers and detractors but continues to flourish. Alongside the basic premise that the position of the moon influences the development and growth of plants, there has arisen a plethora of supplementary rules and refinements which create a confused picture. Inevitably there is disagreement between the advice given from different providers of lunar planting guides. This could lead to dismissing the value of the practice.

In it's simplest form, aligning gardening activities with the amount of moonlight and/or the amount of moisture in the soil has a compelling logic. It's up to the reader to decide for themselves how seriously they want to follow lunar advice. It would, however, be reasonable to suppose that a gardener who is referring to a lunar calender is taking the art of gardening seriously, and as such will likely be seeing better results in their own garden.

Read 4283 times Last modified on Wednesday, 29 August 2012 15:08
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