Pairs well with
The Avert Terp Fresh Humidity Indicator Card is a passive colour-change RH reader for jars, storage containers, and curing setups. Drop one in, give it a few hours, and the inner circle shifts colour to match a relative humidity reading on the outer chart. No batteries, no calibration, no fuss. Designed to pair with Avert Terp Fresh 2-way humidity packs — the pack controls, the card confirms.
Specifications
- This is a reader, not a controller. It tells you the current RH. To actually hold a target RH, pair it with an Avert Terp Fresh humidity pack.
- Give the card a few hours to equilibrate after sealing the container. A reading taken seconds after the lid closes won't reflect the steady-state RH.
- Cards eventually lose responsiveness. If the colour stays stuck or doesn't shift when conditions change, replace it. That's why we sell them in 10 and 50 packs.
- Heat and direct sunlight throw the reading off. Read the card at room temperature, away from light, for the most accurate result.
How to Use
Pairs Well With
2-way humidity pack sized for small jars. Pair one with each indicator card to hold a steady 62% RH.
Avert Terp Fresh 28gQuarter-jar humidity pack — the workhorse size for serious curing setups. Pair with one card per jar.
Avert Terp Fresh 460gBulk-bin humidity pack for pound-scale storage. One card lets you monitor the whole bin at a glance.
Full Avert RangeCarbon-lined smell-proof bags, foil-fresh storage and the full Terp Fresh humidity range — same brand, every part of the workflow.
Frequently Asked Questions
Does the card control humidity, or just measure it?
It measures only. The card is a passive indicator — it reads the current RH inside your container and tells you what it is. To actively hold a target RH (e.g. 62%), pair it with an Avert Terp Fresh humidity pack.
How long does each card last?
It depends on conditions, but expect months of reliable reading in a steady environment. Replace the card if the colour stops shifting in response to RH changes — that's why we sell 10 and 50 packs.
How accurate is the reading?
Good enough for curing and storage decisions, not lab-grade. Cards give you the current RH within a reasonable band — accurate enough to know whether you're at 55%, 62%, or 70%. For precision monitoring, use a digital hygrometer alongside.
Can I put more than one card in a single jar?
Yes, but there's no benefit. The cards read the same air, so one is enough per sealed container. The 10 and 50 packs are sized for running multiple jars or replacing cards as they age, not stacking them.
Does this ship free?
Yes — free shipping over $499* applies. The indicator cards are small and light, so they ship standard parcel with no bulky-item surcharge.
Select Pack Size
Read It. Know It. Hold It.
Colour-change RH reading for every jar — pair with Terp Fresh packs to hold the line.