Gardening by the moon is the old practice of timing garden jobs by the lunar cycle. The basic rule: sow crops that fruit or leaf above ground while the Moon is waxing, from new to full, and root crops, bulbs and perennials while it's waning, from full back to new. Some traditions also use the Moon's zodiac sign. It's a long-lived folk tradition rather than a tested method. Reviews of the science have found no reliable evidence that the Moon's phase changes how plants grow, but a moon calendar can still be a useful way to garden regularly and pay attention.
The basic rules
The most widely printed version, found in many almanacs, splits the month into two halves.
The light of the Moon (waxing, new to full) is for annual flowers and vegetables that bear their crop above ground.
The dark of the Moon (waning, full to new) is for bulbs, biennials and perennials, and for vegetables that bear their crop below ground.
Many moon gardeners go further and work by quarters:
- First quarter, new moon to first quarter: leafy annuals such as lettuce, spinach, cabbage, kale and herbs grown for their leaves.
- Second quarter, first quarter to full moon: fruiting annuals such as tomatoes, beans, peas, peppers, squash and melons.
- Third quarter, full moon to last quarter: root crops such as carrots, beets, potatoes and onions, plus bulbs, perennials, fruit trees and transplanting.
- Fourth quarter, last quarter to new moon: no planting. Weed, prune, turn the compost, mend the fence, rest the soil.
Expect variation. Some calendars put transplanting under a waxing Moon, some prefer the days just after the new moon for sowing anything, and some move harvest to the waning half on the grounds that crops keep better. To follow along, our moon phase today page shows the current phase, and waxing vs waning moon explains how to tell the two halves apart by eye.
Planting by the signs
An older layer of the tradition, especially strong in rural American almanac culture, is "planting by the signs": timing work by the zodiac sign the Moon is passing through, which changes every two or three days.
Almanac lists usually divide the signs like this:
- Most fertile: the water signs, Cancer, Scorpio and Pisces. Best for sowing and transplanting.
- Productive: the earth signs Taurus and Capricorn, and air sign Libra. Good for root crops and general planting.
- Barren: Aries, Gemini, Leo, Virgo, Sagittarius and Aquarius. Kept for weeding, clearing, harvesting and killing pests rather than sowing.
Old almanacs printed the "Man of Signs," a figure with each body part assigned a sign, from Aries at the head to Pisces at the feet, and readers used it to judge the Moon's position at a glance. If you want to know which sign the Moon is in on a given day, enter the date into our moon sign calculator, and for what astrologers associate with each sign, see the Moon through the zodiac.
Biodynamic calendars
Biodynamic farming adds the most elaborate version. It grew out of a series of agriculture lectures the Austrian philosopher Rudolf Steiner gave in 1924, and its best-known calendar was developed by the German gardener Maria Thun from the mid-twentieth century onward.
Thun's calendar sorts days by the constellation the Moon is in front of, measured against the actual stars rather than the tropical zodiac most Western astrology uses, and groups them by element:
- Root days, Moon in an earth constellation (Taurus, Virgo, Capricorn): sow and tend carrots, potatoes, onions.
- Leaf days, water constellation (Cancer, Scorpio, Pisces): lettuce, spinach, cabbage.
- Flower days, air constellation (Gemini, Libra, Aquarius): flowers and flowering plants.
- Fruit and seed days, fire constellation (Aries, Leo, Sagittarius): tomatoes, beans, grains.
Biodynamic growers also use specific compost and field preparations, and certification is handled by its own organizations. It isn't the same thing as organic gardening, although the two overlap.
What the evidence says
The honest summary is that the case for a direct lunar effect on plants is weak.
A 2020 review in the journal Agronomy, by researchers at the University of Valencia, went through plant science textbooks and the peer-reviewed literature and found no reliable, science-based evidence linking lunar phases to plant physiology, and no support from physics for a mechanism. A University of Illinois Extension article summarizing that review points to the two usual candidates and why they fall short:
- Gravity. The Moon's pull is far too slight to move water in a plant or the soil in any meaningful way. Tides happen across whole oceans; there's no tide in a seed tray.
- Moonlight. Even a full moon is many thousands of times dimmer than daylight, far too faint to power photosynthesis or change a plant's growth.
There are a few intriguing findings in plant biology, such as a desert shrub reported to release more pollen around the full moon, perhaps for pollinators that fly by moonlight, but nothing that supports sowing lettuce on a particular day for a better crop. Much of the published support for lunar gardening comes from small, loosely controlled trials or from self-published books.
Why moon gardeners still swear by it
None of that has stopped generations of good gardeners from using the Moon, and it's worth understanding why.
- It gives you a schedule. A calendar that tells you to sow leafy crops this week and weed next week gets you into the garden regularly. Regular attention is the single most reliable route to a good garden.
- It spreads the work. Sowing in batches across the month gives you a longer, steadier harvest than sowing everything on one sunny Saturday.
- It encourages notes. Moon gardeners tend to keep records, and records make you a better gardener whatever system they're organized by.
- It connects you to the season. Looking up at the Moon after an evening in the garden is a pleasure in its own right.
A sensible moon-garden calendar
If you'd like to try it without letting it overrule good practice:
- Start with the real limits. Your last and first frost dates, the soil temperature, and the seed packet's advice come first.
- Within that window, choose moon days if you like. If the packet says sow carrots from mid-April and a waning Moon starts on the 20th, sow on the 20th.
- Never skip a good day for a bad one. If the soil is perfect and rain is coming, sow, whatever the phase.
- Run a small trial. Sow half a row of beans in the waxing half and half in the waning half, in the same bed, and compare. It's a simple experiment, and a satisfying one.
- Keep a garden notebook. Date, phase, weather, what you sowed and how it did.
The Seven of Pentacles, a gardener leaning on his hoe and looking at what he's grown, is the tarot's portrait of that patient attention. You can read its meaning on the Seven of Pentacles card page.
Questions readers ask
Does the Moon affect seed germination?
There's no reliable evidence that it does. Germination depends on soil temperature, moisture, seed quality and sowing depth. If moon-timed seeds seem to do better, the cause is more likely to be the weather or extra care than the Moon.
Should I harvest at the full moon?
Some traditions say crops harvested under a waning Moon store better, and others prefer the full moon for picking fruit. Neither is backed by evidence. Harvest when crops are ripe and the weather is dry, which matters more for storage than any phase.
Is biodynamic gardening the same as organic?
No. Organic growing avoids synthetic fertilizers and pesticides. Biodynamic growing does the same, but adds its own preparations, a whole-farm philosophy and a planting calendar based on the Moon and stars, with separate certification.
Does gardening by the moon work for houseplants?
The same evidence applies indoors: light, water, temperature and potting mix are what matter. But if a monthly moon reminder gets you checking your houseplants, it's doing them a favor. Our new moon calendar makes a handy monthly cue.
