58% to 62% relative humidity is the target for curing cannabis, and 62% RH is the figure most growers use. Flower held in that window cures without mold, keeps its terpenes, and burns clean. Above 65% RH mold and rot take hold; below 55% the cure stops and the bud turns harsh and brittle.

Cannabis Dry and Cure Humidity Chart: Target RH by Stage

Why is 58% to 62% RH the sweet spot?

At 58% to 62% RH, water activity in the flower sits near 0.60. That level is dry enough to stop mold and bacteria, and wet enough for the enzymes that break down sugars and chlorophyll during the cure.

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Chlorophyll is what makes fresh weed taste like hay and burn harsh. The cure lets it break down. Terpenes also stay in the flower at this humidity instead of evaporating.

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What humidity should you run while drying?

Drying and curing are two stages with two different humidity targets. Dry first at 45% to 55% RH and 60°F to 70°F for 7 to 14 days. Small stems should snap instead of bending when the dry is done.

Will Low Humidity Ruin Drying Weed

If you skip the dry and go straight to 62% RH with wet flower, you get mold. Most jar mold starts with flower that went in too wet.

How do you measure humidity in a curing jar?

Use a small digital hygrometer that fits inside the jar. Calibrate it first with the salt test: seal it in a bag with damp salt for 8 to 12 hours and check the reading, which should land at 75% RH.

Cheap hygrometers can be off by 8 points or more, so verify before you trust the number. A quick check saves a whole harvest.

How do you hold 62% RH through the cure?

Two-way packs add or absorb moisture to hold the target. They do not fix wet flower, and they do not replace burping in the first two weeks.

What is the burping schedule?

Burping swaps stale air for fresh air and lets excess moisture out. Open each jar for 5 to 10 minutes, then seal it again.

  1. Days 1 to 7: burp twice a day.
  2. Days 8 to 14: burp once a day.
  3. Week 3 and beyond: burp once a week.
  4. Once the reading stays between 58% and 62% for a week, you can stop.

If the hygrometer reads above 65% at any point, leave the jar open longer and inspect for mold.

What happens if the humidity is too high?

Above 65% RH, mold and bud rot can grow inside the jar. You may smell ammonia or a wet basement note before you see fuzz.

A hay or grass smell is a different problem. It means the cure has not broken down chlorophyll yet, or the flower dried too fast before it went into the jar.

What happens if the humidity is too low?

Below 55% RH, the cure stops. The flower keeps a harsh, green taste and the smoke bites at the throat.

Terpenes leave dry air fast, so low humidity costs you flavor and smell. Once flower drops below 50% RH, a humidity pack can soften it, but you cannot restart the cure.

Does temperature matter during the cure?

Yes. Keep curing flower between 60°F and 70°F. Warm rooms speed terpene loss and give mold a better chance.

Light breaks down THC and terpenes, so store jars in a closet or cabinet. A cool, dark shelf does more for quality than any gadget.

How long does curing take?

Two weeks gives you a smokable product. Four to eight weeks gives you the flavor most people want. Some growers cure for three to six months and report more depth, though the returns flatten after about eight weeks.

FAQ

Is 62% or 58% better for curing cannabis?

62% RH is the safer start, and 58% works well for long storage or for humid climates. Both sit inside the cure window. Start at 62% and let the flower settle toward 58% over a few months.

Can you cure cannabis at 70% humidity?

No. 70% RH is mold territory. If a jar reads 70%, open it, spread the flower on a tray for an hour, and recheck. Repeat until the reading drops under 65%.

Do humidity packs replace burping?

No. Humidity packs hold a steady reading, but burping still matters in the first two weeks because it clears gases from the cure. Use both.

What if my cannabis went into the jar too wet?

Take it out. Spread it on a screen or tray at 45% to 55% RH until the stems snap, then jar it again. Mold can show up in 24 to 48 hours, so check each jar.