How to Season a Humidor: Step-by-Step, and How Long It Takes
Humidor setup · Seasoning · Updated 2026-07-22
Seasoning a humidor means letting the bare Spanish cedar absorb moisture until it stops stealing it from your cigars. With Boveda 84% RH seasoning packs the accepted answer is 14 days with the lid shut; with a damp sponge of distilled water on a barrier it is usually 3 to 7 days, checked daily. Either way you are done when the box holds your target band for a full 24 hours with nothing added.
The top results contradict each other because they describe different methods with different endpoints, not because they disagree. This guide puts the methods side by side, gives the day-by-day progression, and tells you what to check when the box will not hold.
Why an unseasoned humidor dries cigars out
Kiln-dried Spanish cedar leaves the factory well below its equilibrium moisture content. Put cigars in that box and the dry wood pulls vapour out of the air, the air pulls it out of the cigars, and the humidifier runs itself dry keeping up. That is why new humidors crack wrappers within a fortnight. Seasoning brings the wood to equilibrium first.
Seasoning method comparison
| Method | Elapsed time | Open the lid? | RH at completion | Main risk | Best for |
|---|---|---|---|---|---|
| **Boveda 84% RH seasoning packs** | 14 days | No - closed the whole time | Wood settles around 68-72% once packs are swapped for your storage RH | Slowest; tempting to peek and reset the clock | New desktop boxes, cabinets, anything you want hands-off |
| **Damp sponge, distilled water, on a barrier** | 3-7 days, sponge re-wetted as needed | Yes - checked and re-wetted daily | Hold 70-75% for 24 hours, then let it settle to your band | Over-humidification and standing water if the sponge drips | Desktop humidors when you want it usable this week |
| **Shallow dish of distilled water** | 5-10 days | Yes - topped up every day or two | Same 70-75% before settling | Slowest evaporation of the wet methods; spills if the box is moved | Larger cabinets and shelved humidors with room for a dish |
| **Propylene glycol solution in the humidifier** | Runs alongside any method above | N/A | PG solutions are formulated to hold near 70% | Alone it seasons the air, not the wood, so it is a supplement | Foam or crystal humidifier units already fitted to the box |
| **Wipe-down with a damp cloth** | 1-3 days | Yes | Rises fast, then falls back | Raises the grain, can buckle or crack thin cedar, and shocks the wood; Boveda and several high-end makers advise against it | Nothing - widely discouraged on unfinished interiors |
| **Tupperdor or wineador (no raw cedar)** | Hours to 1 day | Yes | Straight to your storage band | None significant; plastic and glass absorb nothing | Sealed plastic boxes and converted wine coolers with cedar trays only |
The water must be distilled. Tap and spring water carry dissolved minerals that crust and clog humidifier foam, plus the microbial load that turns a warm 75% box into a mould problem. The sponge also never touches the cedar: direct contact soaks one patch and raises the grain there while the rest of the box stays dry.
The distilled-water sponge method, step by step
- Calibrate the hygrometer first: A saturated sodium chloride solution holds a small sealed container near 75% RH at room temperature; the values are tabulated in ASTM E104, Standard Practice for Maintaining Constant Relative Humidity by Means of Aqueous Solutions (NaCl near 75.3% at 25 C). Salt plus a few drops of distilled water in a cap, bagged with the gauge for at least 8 hours and preferably a full 24, then note the offset. Digital gauges settle faster than analog ones, so give an analog dial the longer window. An uncalibrated gauge is the commonest cause of a humidor that 'will not season'.
- Wet a new sponge and put it on a barrier: Clean and unused, no soap or antibacterial treatment. Saturate with distilled water, squeeze until damp and not dripping, and set it in a small glass dish or on a sealed zip bag. It must not touch the cedar anywhere, including the lid tray.
- Charge the humidification device: Fill it now with distilled water or PG solution so it is part of the equilibrium, not a dry sponge you add at the end.
- Close the lid, check daily: Expect a fast climb into the 70s on day one. Re-wet the sponge whenever it is dry to the touch. Watch the shape of the curve, not any single reading.
- Run the 24-hour finish test: Remove the sponge, set the device to your storage RH, and leave the box alone for a day. Holding the target band for 24 hours untouched means it is seasoned; sagging more than 3 to 4 points means it is not.
Day-by-day RH you should expect
| Day | 84% pack method | Sponge / dish method | What it means |
|---|---|---|---|
| 1 | 70-78% | 72-80% | Air fills fast. The wood has barely started. |
| 2-3 | 76-82% | 70-76% and dropping between re-wets | The drop between checks is the wood drinking. This is the useful signal. |
| 4-5 | 80-84% | 70-75%, holding longer each day | Sponge method boxes are often close here. |
| 7 | 82-84% | Steady 70-75% for a day or more | Most of the moisture transfer is done; the rest is depth. |
| 10 | 83-84%, flat | Ready for the finish test | A flat line for several days is the real endpoint. |
| 14 | 84%, flat - swap to storage packs | Already in service | Wood settles to roughly 68-72% after the swap, then to your band. |
Worked example. A 100-count desktop humidor needs one 60 g 84% pack per roughly 25 cigars of capacity, so four packs. Day 1 reads 74%, day 3 reads 79%, day 7 reads 83%, days 10 and 12 both read 84%. Two flat days in a row means the cedar has stopped taking moisture. Pull the packs on day 14, drop in storage packs, and the box drifts to the high 60s over the next week. That drift is normal, not a leak.
Log one reading a day and watch the curve flatten. Guessing from memory is why people re-season boxes that were already done. In Cigar Humidor & Journal, Monitor logs a humidity and temperature reading per humidor, shows the recent trend with min, average and max, and calls each reading in band or out of band against the target band you set. Log once a day through seasoning, watch the trend flatten, then set the band before the first stick goes in. No account, works offline. Download Cigar Humidor & Journal on the App Store.
If it will not hold the band
- Re-check the hygrometer first. A gauge reading 5 points low has you chasing a leak that does not exist. Redo the ASTM E104 salt test and apply the offset.
- Dollar bill test the seal. Close the lid on a banknote and pull. You want friction on every side and at the corners; where a bill slides free is where your humidity is going.
- Drop test the lid. Let it fall from a few inches. A sealed box lands on a cushion of escaping air; a hard slam means the seal is not compressing.
- Check for lid warp. Sight along the rim in good light. A box that sat in a dry shop can bow, and several days at high RH often pulls it flat again.
- Look at the room. A humidor in a 40% RH air-conditioned room fights a far steeper gradient than one at 55%.
Setting the target band before the cigars go in
The last step is deciding what the box should hold, and writing it down. Most collectors settle between 65% and 70% RH; the humidor humidity chart covers how that interacts with temperature and beetle risk. In Cigar Humidor & Journal you set a target band per humidor, so every logged reading is judged against that box rather than a generic number, and drift above 70% RH raises an out-of-band alert. Once the box is in band, the Vault takes over: inventory and value per humidor, aging status per lot, and a tasting journal for the first stick out of a box you finally trust.
Frequently asked questions
How long does it take to season a humidor?
Fourteen days with 84% RH seasoning packs and the lid closed, or roughly 3 to 7 days with a damp distilled-water sponge checked daily. Thick-walled cabinets take longer. The real endpoint is the same either way: the box holds your target band for 24 straight hours with no intervention.
Can I season a humidor with tap water?
No. Tap and spring water carry dissolved minerals that clog humidifier foam and leave residue on cedar, plus microorganisms that can seed mould in a warm box at 75% RH. Use distilled water, or a propylene glycol solution in the humidification device.
Should I wipe down the inside of a new humidor?
Most makers now advise against it. Wiping soaks the surface only, raises the grain of finely sanded Spanish cedar, and can buckle or crack thin panels while leaving the interior of the wood untouched. Boveda explicitly rejects the wipe-down method, and high-end makers warn it roughens the finish.
Do I open the humidor while seasoning with Boveda?
No. The 14-day figure assumes the lid stays shut for the full period regardless of what the hygrometer says. Every opening dumps the humid air you have built and restarts the gradient the cedar is absorbing across.