Waxing or waning moon: when to sow, plant, and prune?

“Sown during a waxing Moon,” “pruned during a waning Moon,” “planted during a waning Moon”... This advice is found everywhere, but in reality it mixes up two completely different cycles that almost never overlap.

This is the number one source of confusion in lunar gardening, and it makes most of the advice read online unusable. Let's start by disentangling the two.

Two cycles, not to be confused

Waxing or waning—what you can see

This is the cycle of the phases, the one we observe in the sky: the illuminated portion grows from new moon to full moon (waxing), then decreases until the next new moon (waning). Duration: about 29 and a half days.

It is an illumination phenomenon related to the relative positions of the Sun, Earth, and Moon.

Ascending or descending—what you cannot see

This is a completely different cycle: that of the Moon's height above the horizon from one day to the next. Over about 27 days, it rises higher and higher in the sky (ascending), then descends (descending)—exactly as the Sun does over an entire year between the winter and summer solstices.

This cycle has nothing to do with the Moon's appearance: it can be full and descending, or a waning crescent and ascending.

The table that prevents mistakes

Because the two cycles are not the same length, they continually shift relative to each other. That is why one cannot be deduced from the other: you need a calendar. It is also why so much advice found online contradicts itself—its authors are talking about two different things while believing they are talking about the same thing.

Root, leaf, flower, and fruit days

A third division is added, originating in the biodynamic tradition: depending on the constellation the Moon passes in front of, the day is supposedly favorable to one of the plant's organs.

• Root days — carrots, beets, turnips, radishes, potatoes
• Leaf days — lettuce, spinach, cabbage, herbs
• Flower days — flowers, broccoli, artichokes
• Fruit days — tomatoes, squash, beans, fruit trees

This is the division found in most commercially available lunar calendars. It combines with the two preceding cycles, resulting in a fairly dense system—which is why a ready-made calendar is more useful than calculations you have to redo.

What science honestly says about it

It is better to be clear about this than to leave room for doubt.

• The tidal effect on soil is negligible. Lunar attraction moves oceans because they are vast and fluid; in the water contained in a garden bed, the force involved is infinitesimal.
• Controlled studies have found no reproducible effect of lunar phases on germination or yield.
• Moonlight, on the other hand, does exist. It is very faint, but some organisms are sensitive to it — this has been documented in several animal species. In cultivated plants, no practical effect has been established.

Should you throw away the lunar calendar, then? Not necessarily, and for a reason that has nothing to do with mysticism: it provides a work rhythm. A gardener who follows a lunar calendar goes into the garden regularly, plans their tasks, and spreads out their sowing instead of doing everything on the same weekend. These are genuinely good practices — and they are enough to explain the results attributed to it.

Our position: use it as a planner and for enjoyment, not as science. And never sacrifice a factor that really matters for it — sowing in soil at the right temperature on the “wrong” day is infinitely better than the opposite. See How to sow seeds.

How to use it in practice

If you want to try it, here is the most sensible way to use it.

1. Use it to organize, not to decide. The calendar tells you which day is generally good for a given task; soil temperature and the weather tell you whether it’s possible. The latter always take priority.
2. Remember the simple rule: waxing moon for what grows upward (sowing, grafting, harvesting above-ground parts), waning moon for what goes downward (planting, transplanting, pruning, taking cuttings, working the soil).
3. Group your tasks. This is where the calendar is genuinely useful: it has you do all your transplanting on the same day instead of whenever you feel like it.
4. Don’t feel guilty about “missing” a day. Seeds sown two days later grow exactly the same.
5. Record your results. If you really want to know, test it: two identical rows of radishes, on different days, and compare them over several seasons. It’s the only way to form an opinion about your garden.

What really influences your sowing

In descending order of importance, here is what really determines success:

1. Soil temperature — by far the most important factor. A thermometer costing a few euros replaces all calendars.
2. Consistent moisture — a seed that swells and then dries out dies.
3. Sowing depth — two to three times the seed's diameter.
4. The freshness of the batch and the quality of the seed.
5. Light after emergence — the number one cause of leggy seedlings.

The lunar calendar comes after all this. If a sowing fails, look for the cause in this list before blaming the Moon.

Frequently asked questions

How can you tell whether the Moon is ascending or descending?

By observing its height above the horizon on two consecutive evenings, at the same time and in the same place. If it is higher, it is ascending. In practice, a calendar is much simpler.

Are a full moon and an ascending Moon the same thing?

No, and this is exactly the confusion to avoid. A full moon is a phase; ascending describes a trajectory. A full moon can be ascending or descending depending on the month.

Should you really avoid sowing during the waning Moon?

Nothing requires it. Tradition reserves the waning Moon for tasks focused on the soil, but seeds sown at that time will normally germinate if soil conditions are good.

Does the lunar calendar work for mushrooms?

No data establishes this. Mushroom fruiting depends on humidity and thermal shocks, two well-identified factors. See How to grow mushrooms at home.

Where can I find the up-to-date calendar?

We keep it on our dedicated page, with the phases, root/leaf/flower/fruit days, and the saying of the day: Gardening with the Moon.

Key takeaway

Waxing/waning describes what you see; ascending/descending describes a trajectory invisible to the eye. The two cycles are constantly shifting relative to each other, hence the need for a calendar. Use it as an agenda that gets you out into the garden regularly—that is its real benefit—and always let soil temperature have the final say.

To go further

• Gardening with the Moon: lunar calendar and sayings
• The complete month-by-month calendar of gardeners' sayings
• The month-by-month sowing calendar
• How to sow seeds in cotton, seed trays, or directly in the ground

To put it into practice: our spring sowings, our year-round sowings, and our vegetable garden seeds.