Quick answer
For cured flower in a jar, 62% is the usual pick. It sits inside the 55 to 65% RH range that keeps buds springy and aromatic without inviting mold. Go lower, around 58%, if you prefer a drier, faster-burning smoke or live somewhere humid. Do not store above 65%. Size matters as much as the number: use one 8 g pack per ounce.
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The number on a humidity pack is the relative humidity it steers a sealed jar toward. A two-way pack gives off moisture when the jar is drier than that number and takes moisture in when the jar is wetter. So the real question is what humidity you want your flower to live at.
The safe window is 55 to 65%
The industry reference is ASTM D8197, which sets a water activity of 0.55 to 0.65 for stored dry cannabis flower. In a sealed jar that works out to about 55 to 65% RH.
- Below the window buds turn brittle, trichomes break off in the grinder, aroma fades faster and the smoke gets harsh.
- Above the window the risk of mold rises, and it rises quickly in a warm room.
Both 58% and 62% sit inside the window. The choice between them is about how you like your flower, not about safety.
58% vs 62%, side by side
| 58% | 62% | |
|---|---|---|
| Feel of the bud | Drier, snaps more easily | Springy, slightly sticky |
| Burn | Lights easily, burns faster | Slower and more even |
| Aroma | Good | Fuller, for most people |
| Often chosen for | Pre-rolls, humid climates, a drier smoke | Jar storage of cured flower, long keeping, dry or heated homes |
| Watch for | Flower that is already on the dry side gets drier | Flower jarred too wet: no pack fixes that |
Humidi-Cure for cannabis is made at 62% RH (±2%), the level most home growers and storage guides settle on for cured flower in jars.
Why not 65%, 69% or 72%?
Those numbers are made for cigars, which are kept much more humid than cannabis. A 69% or 72% pack in a jar of flower pushes it out of the safe window. If you keep cigars too, this guide covers 65% vs 69% vs 72% in a humidor. Keep the two collections apart.
Do you need a humidity pack at all?
Not always. A pack earns its place when:
- You keep flower for more than a couple of weeks
- The jar gets opened often
- Your home is dry, heated in winter or air-conditioned in summer
- The jar is much bigger than what is in it
If you finish a small amount within a week or two from a full, airtight jar, you can skip it.
One thing a pack is not: a dryer. It holds flower that is already cured. It cannot rescue buds that went into the jar wet. Check first with how to tell weed is dry enough to jar, and if a jar already feels damp, read what to do with moist weed.
The size matters as much as the number
A pack that is too small for the jar cannot hold its number, whatever is printed on it. Match the pack to the amount of flower.
| Flower in the jar | Pack size |
|---|---|
| 1/8 oz | 1.5 g |
| 1/4 oz | 3 g |
| 1/2 oz | 4 g |
| 1 oz | 8 g |
| 1/2 lb | 63 g |
For anything in between, use the pack size calculator or the guide to how many packs per ounce. Two more rules: keep one humidity level per jar, and do not mix different humidity products in the same jar.
Stock up for the jars you have
One 8 g Humidi-Cure 62% pack per ounce jar. The plant-fiber core has no liquid or gel inside, so there is nothing to leak onto your flower.
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Any 2 boxes save 10%, and U.S. orders of $40 or more ship free.
Frequently asked questions
What percentage humidity pack is best for weed?
62% is the usual choice for cured flower stored in jars. 58% suits people who prefer a drier smoke or live in a humid climate. Both sit inside the 55 to 65% RH range used for storing dry flower.
Is 62% humidity too high for weed?
No. 62% is inside the 55 to 65% storage range. Trouble starts above 65%, or when flower is jarred before it is dry enough.
Is 58% or 62% better for curing?
Most home growers cure and store at 62% for a fuller aroma and a springier bud. Choose 58% if your flower tends to come out too moist or you like it drier.
Will a humidity pack dry out wet weed?
No. A pack holds flower that is already dried and cured. Wet flower needs to be dried properly before it goes into a jar with a pack.
When should I replace a humidity pack?
See when cannabis humidity packs expire and when to replace them.
Buying for a dispensary, a cultivation site or a brand? See wholesale and custom-printed packs.
