In the closing lines of the oldest surviving farmer’s almanac, written around 700 BCE, the Greek poet Hesiod listed lucky and unlucky days for planting. Day thirteen of the waxing moon, he wrote, was bad for sowing seed but the best day for setting plants. Day six of the mid-month was very unfavorable for vegetation. Day twenty was best for the birth of a wise person.
The poem is called Works and Days. It ends with a lunar calendar so specific that a Greek farmer could follow it tomorrow.
Twenty-seven centuries later, the Old Farmer’s Almanac still prints a moon planting guide. So does the Llewellyn Moon Sign Book, in continuous publication since 1905. So do a hundred apps on the App Store. The Maori of New Zealand name each night of the lunar month and assign planting guidance to every one. The Dogon of Mali plant millet during the waxing moon and yams during the waning, a rule identical to what Columella wrote in Rome two thousand years ago.
Nobody has settled whether this is the longest-running agricultural practice on earth or the longest-running mistake.
The Chain Begins in Greece
Hesiod was a Boeotian farmer writing for farmers. The second half of Works and Days is a practical agricultural calendar, starting with the rising of the Pleiades as the signal to harvest and ending with the lunar day-count. His Greek months were thirty days long, each beginning with the new moon and divided into three periods: waxing, mid-month, and waning.
He was specific. Days eight and nine of the waxing month are “specially good for the works of man.” Day eleven and twelve are both excellent for reaping. Day thirteen is bad for sowing but best for transplanting.
Hesiod’s audience would have starved if they planted wrong. The lunar calendar was a working tool, and the specificity shows it.
Hesiod’s Works and Days (c. 700 BCE) is the oldest surviving farmer’s almanac. A manuscript copy from 1316, now in Venice’s Biblioteca Marciana, preserves the agricultural calendar section with medieval commentary still debating the correct planting days.
Rome Writes It Down
The Romans turned Hesiod’s poetry into bureaucratic precision. Between 160 BCE and the fifth century CE, at least six major agricultural authors recorded lunar planting rules, and they agreed on the basics.
Cato the Elder, writing around 160 BCE in the oldest surviving Latin prose work, prescribed grafting figs, olives, and vines “in the dark of the moon, after noon, when the south wind is blowing.” Timber should never be touched “except in the dark of the moon or in its last phase.” Manure goes on the meadows when the moon is dark.
Virgil’s Georgics (29 BCE) states that the moon “has set certain days as auspicious for certain kinds of work.” He marks the seventeenth day after the new moon as lucky for planting vines. The scholar Eugene Tavenner, in a 1918 paper for the American Philological Association, pointed out that this contradicts the general waxing-moon rule. Virgil knew the rule and broke it.
Columella, writing around 65 CE, produced the most detailed practical guidance. His De Re Rustica runs to twelve volumes. Sow seed crops during the waxing moon, he wrote, when the lunar light is growing. Harvest root crops and timber during the waning moon, when moisture is decreasing. Beans go in on the fifteenth day or on the full moon itself.
Pliny the Elder, in Book XVIII of his Natural History (77 CE), explained the mechanism: the new moon brings slight dew that gradually increases to maximum at the full moon. Roman farmers believed the moon governed moisture, not light. Timber felled at the dark moon (the interlunium) was “universally agreed” to be most durable.
By the time Palladius wrote his month-by-month farm calendar in the late fourth century, the rules had hardened into a system: “All planting should be done when the moon is increasing.” His work organized everything by calendar month, which made it the most copied agricultural text in the medieval period. When Pietro de’ Crescenzi compiled Ruralia Commoda in Bologna between 1304 and 1309, harmonizing Roman sources with medieval experience, the lunar rules crossed into print culture. Crescenzi’s book became the first printed agricultural text in 1471 and went through fifty-seven editions in four languages.
The written chain runs unbroken from Hesiod through Cato, Virgil, Columella, Pliny, Palladius, and Crescenzi to the almanac on your phone.
The Same Rule, on Every Continent
The Romans wrote it down. But the same basic rule also appears on continents that had no contact with Rome.
In West Africa, the Dogon, Mandinka, and Fulani plant above-ground crops (millet, maize, groundnuts) during the waxing moon and root crops (yams, cassava) during the waning. Their calendar counts thirteen months by lunar phases, with years defined by observing the Pleiades. The correspondence with Columella is exact: above-ground crops in waxing light, root crops in waning.
Cherokee traditional farming also aligns planting with the waxing moon for stronger growth and higher yields, and harvesting certain plants during the waning moon for better storage life. Andean communities time pruning, planting, and harvest to the lunar cycle, with the heliacal rising of the Pleiades marking the start of the potato season.
The Maori Maramataka names each of the 29-30 nights of the lunar month. Specific planting nights for kumara (sweet potato) include Ouenuku (4th night), Ari (9th), and Rakau-nui (16th). The Korekore nights (20th-22nd) and the full moon are marked as no-planting periods.
The Maori system is the most detailed non-European lunar planting calendar to survive in documented form. The word Maramataka means “the turning of the moon.” Each night carries guidance not just for gardening but for fishing, travel, and ceremony. Tohunga (expert priests) selected the correct lunar nights for kumara planting, and the timing was confirmed by star positions. This system operated for centuries before any European contact.
The Chinese agricultural calendar (nong li, literally “agricultural calendar”) takes a different path. It integrates lunar months with twenty-four solar terms based on the sun’s position, and the practical farming guidance follows the solar terms more than the lunar phase. The earliest complete list of these terms appears in the Huainanzi (c. 139 BCE). By 104 BCE, they were incorporated into the official calendar. Japan adapted the same system into seventy-two microseasons, each lasting about five days, with names rewritten in 1685 by the court astronomer Shibukawa Shunkai to match the Japanese climate.
India’s Panchang system combines five components: lunar day (tithi), solar day, asterism (nakshatra), planetary joining (yoga), and astronomical period (karanam). The agricultural text Krishi-Parashara, attributed to the fourth century BCE, prescribes specific farming actions for each nakshatra cycle. This is neither the Roman system nor the Chinese one. It is a third approach to the same problem.
The question that nobody can fully answer: why does the basic waxing-for-above-ground, waning-for-root-crops pattern appear in traditions separated by thousands of miles and thousands of years?
The Almanac Age
By the seventeenth century, lunar planting had left the monastery and the manor farm and entered mass culture. The vehicle was the almanac.
The Almanach de Liege, also called the Almanach Mathieu Laensberg, has been published annually since at least 1626. It used symbols so that illiterate readers could follow: a vial for the proper moon phase to take medicine, scissors for cutting hair, a lancet for bloodletting. In eighteenth-century France, the writer Sebastien Mercier estimated its circulation at sixty thousand copies. In seventeenth-century England, almanacs were bestsellers second only to the Bible, with four hundred thousand produced annually by mid-century.
These were not fringe publications. They were the internet of their age: the place where ordinary people looked up what to do and when.
The Old Farmer’s Almanac, founded by Robert Bailey Thomas in 1792, is the oldest continuously published periodical in North America. It still prints moon planting charts and maintains an online planting calendar. Its forecasting formula, developed by Thomas from solar activity observations, is kept in a black tin box at the company’s offices in New Hampshire.
The Farmers’ Almanac (a different publication, founded in 1818) used a pseudonymous forecaster called “Caleb Weatherbee” and its own mathematical formula. After two hundred and eight years of publication, it announced in November 2025 that the 2026 edition would be its last.
Llewellyn’s Moon Sign Book, in print since 1905, bridges the gap between the agricultural almanac and the astrological tradition. It includes week-by-week lunar gardening guidance alongside void-of-course charts and zodiac tables. The Stella Natura calendar serves the biodynamic farming community with similar information.
How the System Works
The simple version uses four lunar phases. Most gardeners and almanacs follow this:
New Moon to First Quarter (Waxing Crescent). Increasing light, rising moisture. Plant above-ground crops that produce seeds outside the fruit: lettuce, spinach, celery, broccoli, cabbage, cauliflower, grain.
First Quarter to Full Moon (Waxing Gibbous). Strong moonlight favors leaf growth. Plant above-ground crops that produce seeds inside the fruit: beans, melons, peas, peppers, squash, tomatoes. Good for transplanting.
Full Moon to Third Quarter (Waning Gibbous). Decreasing light, moisture drawn downward. Plant root crops: beets, carrots, onions, potatoes, radishes, turnips. Also perennials, biennials, and bulbs.
Third Quarter to New Moon (Waning Crescent). Rest period. No planting. Cultivate, harvest, prune, mow, turn compost.
The distinction between waxing for above-ground crops and waning for root crops traces directly to Columella. The four-phase refinement (splitting above-ground crops into two categories) is a twentieth-century almanac addition.
The complex version adds the zodiac. Maria Thun, a German researcher who began experimenting with radish planting in the 1950s, proposed that the zodiac constellation the moon passes through matters as much as the phase:
Root days, when the moon is in Taurus, Virgo, or Capricorn (Earth signs). Leaf days, when it enters Pisces, Cancer, or Scorpio (Water signs). Flower days for Gemini, Libra, or Aquarius (Air signs). Fruit days for Aries, Leo, or Sagittarius (Fire signs).
The moon spends two to three days in each sign, completing all twelve in about 27.3 days.
A third layer, often confused with the first: the ascending and descending moon. This is not waxing and waning. It tracks the moon’s declination, how high or low it rises in the sky over a two-week cycle. When the moon rises higher each day (ascending), sap forces move upward. Good for harvesting fruit and grafting. When it rises lower (descending), forces sink into the roots. Good for planting, transplanting, and composting.
You can have a waxing but descending moon, or a waning but ascending one. The two cycles overlap independently.
Biodynamic practitioners add perigee and apogee (the moon’s closest and farthest points from Earth) and lunar nodes (where the moon crosses the ecliptic). Thun found that planting at lunar nodes affected germination negatively. The recommendation is to avoid sowing six hours on either side of a node passage and twelve hours around perigee or apogee.
Five lunar cycles layered on top of each other. That is the full biodynamic calendar.
Steiner’s Eight Lectures
Rudolf Steiner delivered eight lectures on agriculture at Koberwitz (now in Poland) during Whitsun 1924, six months before his death. One hundred and eleven people attended. All were Anthroposophists. Many were farmers.
Steiner was not a farmer or a scientist. He described “etheric, astral and ego activity of nature” and claimed that soil, plant, and animal health depends on reconnecting with “cosmic creative, shaping forces.” In his first lecture, he stated that “something stupendous takes place on the earth as a result of the full moon’s forces. These forces shoot into all the vegetative growth; but only if the full moon was preceded by some rainy days.” In the fourth lecture, he connected planetary movements and zodiac positions to different plant types.
These are the only agricultural lectures Steiner ever gave. The entire biodynamic movement, its preparations and its calendar, grew from these eight talks and five discussion sessions. The detailed planting calendar used today was developed not by Steiner but by Maria Thun, who spent over forty years testing the system from the 1950s until her death in 2012.
Her Thun Calendar (the Biodynamic Sowing and Planting Calendar) has been published annually since 1963. It remains the primary reference for biodynamic farmers worldwide.
A point worth noting: Demeter, the international biodynamic certification body, does not require lunar timing. Its standards focus on organic practices, preparation use, and biodiversity. Many biodynamic farmers follow the Thun or Stella Natura calendar, but the moon is encouraged, not enforced.
Domaine de la Romanee-Conti, one of the most expensive wine estates on earth, converted entirely to biodynamic methods in 2007 after seven years of trials. Vines are treated according to a lunar timetable. Domaine Leroy has been biodynamic since 1988.
What the Science Says
The comprehensive negative review came in 2020. Mayoral, Solbes, Canto, and Pina examined every agronomy, botany, and plant physiology textbook they could find, plus the scientific literature. Their conclusion, published in the journal Agronomy: “There is no reliable, science-based evidence for any relationship between lunar phases and plant physiology in any plant-science related textbooks or peer-reviewed journal articles justifying agricultural practices conditioned by the Moon.”
That sounds definitive. But the researchers who have actually measured plants tell a more ambiguous story.
Ernst Zurcher, at the Swiss Federal Institute of Technology (ETH Zurich), published a paper in Nature in 1998 showing that tree stem diameters fluctuate with tidal rhythms. The fluctuations were measurable and repeatable. His later work confirmed lunar-correlated phenomena in tree biology and wood properties.
Peter Barlow, at the University of Bristol, found “continuous modulation of root elongation growth by the lunisolar tidal force” in Arabidopsis thaliana (a model plant maintained in constant light). His work, published in Annals of Botany, coined the term “selenonastic” for gravity-tide-related growth effects in plants.
Hartmut Spiess at the University of Kassel designed a rigorous test of Thun’s zodiac system. He planted radishes daily for four-week periods across three years, using randomized complete-block designs with four replications per planting date. The result: he could not replicate Thun’s zodiac findings. The sidereal/constellation effects she described were not apparent. But he did find effects from the tropical cycle (ascending/descending) and the anomalistic cycle (perigee/apogee). Best growth correlated with perigee.
The newest findings come from the moonlight itself. A 2023 study in the journal Plants found that full moonlight triggers gene expression changes in coffee plants. Moonlight has a red-to-far-red ratio of 0.18-0.22, compared to sunlight’s ratio above 1.2. This difference is significant because plants use phytochrome receptors to detect that ratio. Full moonlight may convert the active form of phytochrome to its inactive form, and the plant responds. Heat shock proteins were upregulated. Core clock genes shifted.
A 2025 study in Plant, Cell & Environment found that three consecutive nights of full moonlight exposure “significantly enhanced all growth parameters examined” in Brassica juncea.
Plants perceive moonlight. They respond to it at the molecular level. That much appears to be true. Whether the response is large enough to matter in a garden bed remains unknown.
The gravitational tidal effect on groundwater, confirmed by a study from the University of New South Wales, is real but tiny: a few centimeters or millimeters. Whether that signal matters when compared to rain, irrigation, and evaporation is the open question.
The Pattern That Won’t Disappear
The evidence stacks up in layers that do not quite add up to a conclusion.
The written tradition stretches from Hesiod (700 BCE) through Cato, Virgil, Columella, Pliny, Palladius, Ibn Wahshiyya, Crescenzi, and the European almanacs to the present, covering twenty-seven hundred years of continuous transmission. The same above-ground/waxing, root/waning pattern appears independently in Roman Italy, West Africa, Cherokee country, the Andes, and New Zealand, in traditions that had no contact with each other. Tree diameter fluctuations have been published in Nature, root growth modulation in Annals of Botany, gene expression changes under moonlight in Plants and Plant, Cell & Environment.
No mechanism yet explains why any of this should make a practical difference to your tomatoes.
The rationalist reads the evidence one way: the effects are real but trivial, the tradition persistent but wrong, ancient farmers finding patterns in noise over a field too variable for anyone to control. The counter-evidence fits inside a few journal articles. A fair reading.
But the pattern-based reading has its own weight. The tradition’s universality is hard to explain by chance. The mechanisms are starting to appear in peer-reviewed science, even if the scale is uncertain. The tidal effect exists. The moonlight effect exists. The 2,700 years of practice on six continents exist too.
If you follow the waxing-waning rule, you will be doing what Columella did, what the Dogon did, what the Maori did, and what the vine-keepers at Domaine de la Romanee-Conti do now. Whether the moon drives the result or the calendar forces you to pay closer attention to your garden is something that twenty-seven centuries of observation have failed to settle. Hesiod’s thirteenth day is still waiting for a definitive answer.
Sources
Bibliography. The same list is held in the article’s frontmatter for the citation tools that read it programmatically.
- Hesiod, Works and Days (c. 700 BCE), agricultural calendar section
- Cato the Elder, De Agri Cultura (c. 160 BCE)
- Virgil, Georgics (29 BCE)
- Columella, De Re Rustica (c. 65 CE), twelve volumes
- Pliny the Elder, Natural History, Book XVIII (77 CE)
- Palladius, Opus Agriculturae (late 4th century CE)
- Pietro de’ Crescenzi, Ruralia Commoda (1304-1309; first printed 1471)
- Eugene Tavenner, lunar agriculture paper, Transactions of the American Philological Association (1918)
- Krishi-Parashara (attributed 4th century BCE), Indian agricultural text on nakshatra timing
- Huainanzi (c. 139 BCE), earliest list of the twenty-four Chinese solar terms
- Rudolf Steiner, Agriculture Course (Koberwitz lectures, June 1924)
- Maria Thun, Biodynamic Sowing and Planting Calendar (annual since 1963)
- Mayoral, Solbes, Cantó & Pina, lunar phases and plant physiology review, Agronomy (2020)
- Ernst Zürcher (ETH Zürich), tree stem diameter tidal fluctuations, Nature (1998)
- Peter Barlow (University of Bristol), lunisolar tidal modulation of root growth in Arabidopsis, Annals of Botany
- Hartmut Spieß (University of Kassel), replication trials of Thun’s zodiac sowing system
- Coffee phytochrome and full-moon gene expression study, Plants (2023)
- Brassica juncea moonlight exposure growth study, Plant, Cell & Environment (2025)
- Almanach de Liège (Mathieu Laensberg), continuously published since 1626
- The Old Farmer’s Almanac, founded by Robert Bailey Thomas (1792)
- Llewellyn’s Moon Sign Book, in print since 1905