When to Plant Onions by the Moon: Traditional Days for 2026 and 2027

According to almanac tradition, onions go in the ground during the third quarter of the Moon, the stretch from full moon to last quarter, ideally while the Moon sits in a sign this convention labels fruitful or semi-fruitful. The nearest Traditional days are October 26-27, 2026 (Moon in Taurus) and October 30-31, 2026 (Moon in Cancer). No effect of the Moon on onions has been proven.

What the tradition says about planting onions

The quarter rule

Moon-planting almanacs sort crops into types and tie each type to a quarter of the lunar cycle. Onions fall under the root type, which also covers other root crops, bulbs and perennials. The almanac rule is that this type is planted in the third quarter, after the full moon and before the last quarter. That is the waning half of the cycle, which is why you will see the same advice described as planting in a waning moon. The whole system is laid out on the main page about planting by the moon.

The fourth quarter, from last quarter to new moon, is set aside in the same tradition for rest: weeding, pruning, turning the soil and composting. Nothing gets planted then.

What the Moon can and cannot do

A second layer sits on top of the quarters. Many gardening almanacs also sort the twelve zodiac signs by how fruitful they are, and the Moon passes through a new sign roughly every two and a half days. This convention labels Cancer, Scorpio and Pisces fruitful, and Taurus, Libra and Capricorn semi-fruitful. Aries, Gemini, Leo, Virgo, Sagittarius and Aquarius are labeled barren, though sources differ on Virgo, Sagittarius and Aquarius. A Traditional onion day, then, is a third-quarter day with the Moon in a fruitful or semi-fruitful sign.

Whether any of this matters to an onion is a separate question, and the evidence is not there. The Moon’s tidal pull at the Earth’s surface, calculated from NASA’s lunar constants, peaks at about 1.1 millionths of a meter per second squared. That is roughly one ten-millionth of gravity, far too small to move anything as small as a seed or a root. The phase cycle itself is real and precise (29.53 days from new moon to new moon). The link between that cycle and a bulb in your bed is tradition, and this page treats it that way.

Traditional onions planting days, 2026 and 2027

The table lists every month in the planting range for onions, from October 2026 through 2027. Each row gives the third-quarter days when the Moon is in a sign the convention labels fruitful or semi-fruitful. All times are Eastern (ET).

Reading the rows

The months shown are those when gardeners in much of the country plant onions. Your state may start earlier or later, so only the rows that fall inside your own state’s window count. If your window opens in February, the October rows are not for you, and the reverse is also true.

Days are read at noon ET, and the Moon changes sign during the day. Treat the first and last day of any run as approximate edges. Where a row says Libra/Scorpio, the Moon crosses from one sign to the other somewhere inside that run, and both signs carry a fruitful or semi-fruitful label under this convention.

Month-by-month detail, with the full phase and sign picture for each day, is on the October 2026 moon calendar and the November 2026 moon calendar. Those pages are useful if you want to see how a traditional onion day sits next to the days around it.

Check your state first: when to plant onions where you live

The order of decisions matters more than any single date. Start with your state’s planting calendar for onions. That tells you whether the crop can go in the ground at all, and which weeks are open. Only after that does the Moon come in, and only if you want it.

The full answer for your location lives on the page about when to plant onions where you live. It owns the planting windows, the soil conditions and the frost considerations, so none of those numbers are repeated here. Your state’s cooperative extension planting guide is the other place to look. Planting guides are written for local conditions in a way a lunar table cannot be, because the same calendar day arrives in very different weather in Maine, Georgia and Washington.

Frost dates and soil temperature decide whether onions can go in the ground. The Moon, if you follow it, only chooses among the days that are already open. A traditional day that falls outside your state’s window is not a reason to plant. It is just a date on a table.

In practice, that means laying the two calendars side by side. Mark the weeks your state guide allows. Find the rows in the table above that land inside those weeks. If a row overlaps, you have a traditional day to pick from. If none do, the options are to plant by your state’s calendar alone, or to wait for the next cycle’s third quarter. Both are reasonable, and the tradition itself would not tell you to skip your local season for a lunar date.

One more practical point. The table runs through November 2027, which means a gardener planning ahead can mark a full year of third-quarter days now and sort them against the state guide later. That planning step costs a few minutes with a printed calendar.

A fair way to try it

Gardeners who plant by the Moon often swear by it, and gardeners who don’t often shrug. A home gardener can judge it for their own plot without taking anyone’s word, but only with a design that compares like with like.

1. Split the planting in two. Put half the onions in on a traditional day from the table, and the other half on an ordinary day inside the same week, so weather and soil stay as close as possible.
2. Use the same variety, the same bed or matching beds, the same spacing and the same watering for both halves.
3. Label both halves with stakes or tags that record the planting date and whether it was a traditional day.
4. Keep notes. Write down when seedlings or shoots first appear in each half, then record the harvest date and the results for each.

One season will not settle anything. Weather, a bad patch of soil or a single pest can swamp any difference between the halves, and with a small bed a few onions either way can look like a pattern. Repeating the split over several seasons gives the notes some weight. It is still the only way a home gardener can judge the tradition for their own plot, because no almanac can speak for your soil.

Questions about planting onions by the moon

Does the tradition say to plant onions in a waxing or a waning moon?

A waning moon. According to almanac tradition, onions belong to the root type, which is planted in the third quarter, from full moon to last quarter. The waxing half of the cycle, from new moon to full moon, is assigned to leafy crops in the first quarter and to above-ground fruiting crops in the second.

What if the traditional day falls when my state says not to plant?

Your state’s calendar wins. The tradition only sorts days, it does not override local conditions, and nothing in the almanac rule asks a gardener to plant outside the season. Check the guide on when to plant onions where you live, then look for the next traditional day that falls inside your window, or plant by the state calendar alone.

Do I need to follow the Moon sign as well?

Not for the basic rule. The quarter rule on its own is the simpler version of the tradition, and plenty of almanacs stop there. The sign adds a second filter, and it is the part where sources disagree, so it is the more optional layer. A different school, the biodynamic calendar associated with Maria Thun, ignores fruitful and barren labels and uses root days instead: Taurus, Virgo and Capricorn. That system would count different days than the table above, which is one more reason to treat all of this as a convention you choose to follow, not a fixed rule.

For a closer look at how phases and signs combine across a whole month, the November 2026 moon calendar shows the cycle day by day.