Curing begins only after the marijuana plant has been harvested and sufficiently dried. You cure the dried flowers—not the living plant.
The usual sequence is that you harvest the mature plant, which can be read here (link to our article). Then you want to hang the whole plant or individual branches in a dark, ventilated area. After that, the plant needs to dry slowly–usually about 1 to 2 weeks. After the flowers feel dry outside but remain slightly springy inside is when curing may begin.
Best Readiness Test
Place several representative flowers in a sealed glass jar with a small digital hygrometer for 12–24 hours As the plants are in the jars, we are checking for their relative humidity. When the flower is at 58% to 62% relative humidity it is at the ideal humidity for curing to begin. At 63% to 65% humidity, the plants would be slightly moist. You can open the jar frequently and monitor carefully. If the measure is above 65%, the plant is too wet. Remove the flowers from the jar(s) and continue air-drying. If the relative humidity is below 55%, then your flower is probably overdried, and curing may be limited.
Small stems snapping can be a useful preliminary sign, but jar humidity is more dependable. Large stems may still bend even when the flowers are ready.
How Long to Cure
Keep the flowers loosely packed in airtight glass jars, generally no more than about three-quarters full, in a cool, dark place. From there, open the jars once or twice daily during the first week. Then open the jars every few days during the next two or three weeks. The cure itself should be at least 2 to 4 weeks.
To get some air circulation in the jars, you can very slightly open the jars and shake the flowers inside. A 4 to 8 week cure often produces a smoother aroma and more even moisture. Research describes traditional controlled-air drying as lasting roughly five days to two weeks, with curing following the drying stage.
If the flowers smell like ammonia, feel damp, or show white or gray fuzzy growth, remove them immediately. Ammonia indicates excessive trapped moisture, and visible mold means the material should not be consumed—particularly by anyone who is immunocompromised. You should always be watching your plant from beginning to end. You want to use it to the best and fullest extent that you can.