Start with the target, then buy tools
Cannabis curing works in a narrow humidity band. Aim for 58% to 62% relative humidity (RH). The midpoint is 60% RH. Hold temperature at 60°F to 70°F. Keep jars in the dark. Buy tools that measure the jar, not the room.
What to buy
- Digital hygrometer with stated accuracy of plus or minus 2% RH. Buy two. One can fail or drift.
- Glass jars with sealed lids. Half-pint to quart size. Fill each jar to 75% of volume. Leave 25% headspace.
- Two-way humidity packs rated 62% RH for cure. Use 58% packs for long storage after cure.
- Calibration kit or plain salt for a salt test. Saturated salt holds about 75% RH in a sealed container.
Parameters that matter
- RH: 58% to 62%. Below 55% RH, flower dries past the cure window. Above 65% RH, mold risk rises.
- Temperature: 60°F to 70°F. Stable is better than a perfect number that swings.
- Burping: First 7 days, open jars 10 to 15 minutes each day. Next 2 weeks, open jars every 2 to 3 days. After that, open jars once per week.
- Moisture: Dry flower to about 10% to 12% moisture before jarring. A small stem bends then snaps. Buds feel dry on the surface.
How to calibrate a hygrometer
Place the hygrometer in a sealed bag with a small cup of saturated salt solution. Wait 6 to 8 hours. A good meter reads near 75% RH. If it reads 70%, add 5 points to each jar reading. Repeat the test each season.
Optimizing Your Cannabis Storage with 62% Humidity Packs
Pitfalls
- One uncalibrated hygrometer. A 10-point error can turn a cure into mold or dust.
- Packing jars tight. Buds need air space. Fill to 75% and no more.
- Judging by touch. Use a meter and a calendar.
- Rehydrating with fruit or water. That adds sugar and mold risk. Use a two-way pack.
- Opening jars in a wet room. Do burping in dry air, 40% to 50% RH.
- Mixing batches. One wet jar can raise RH in the whole container.
Buying checklist
Buy two calibrated hygrometers, four to eight glass jars, one 62% two-way pack per jar, and a notebook. Record RH, temperature, and burp dates. Replace packs when they feel stiff or dry. Check jars at 58% to 62% RH before storage. If RH climbs above 65%, burp longer and check for mold at the bud center.