Drying rooms are an integral part of cannabis production. Post-harvest flowers still contain approximately 80% water. This water needs to be removed before the dry buds can be sold or provided to patients.
Drying Rooms Need Humidity Control
Dry rooms are built to remove the excess humidity in plants, after harvest. Though the buds are no longer growing, they’re still alive and continue to evaporate massive amounts of water.
If gone unchecked, the buds’ evaporation will quickly raise relative humidity to 100%. Under these conditions the plants won’t be able to continue drying. This reduces the quality of the product, which in many cases won’t uphold regulations.
Untreated humidity can also result in mold development. Bud rot can break out post-harvest and even after packaging. Of course, moldy cannabis is illegal to provide to patients or sell for recreational purposes. Oils, edibles and topicals manufacturers can’t use infected cannabis either, turning the harvest useless.
One of the greatest challenges facing drying rooms is the need to remove large amounts of water quickly, especially when harvesting an entire grow cycle in a short period of time. When large amounts of produce enter the drying room at once, there’s a massive spike in humidity. This is the most dangerous period for the flowers.
Dehumidifier for Drying Rooms
Growers often turn to heating systems or HVAC in an attempt to deal with the humidity buildup, but the only efficient method to reduce humidity at a sufficient pace is with dehumidification.
While heating does reduce relative humidity, it’s very problematic in drying rooms, which require a cool environment to preserve terpenes and maintain the highest bud quality.
Cooling with an HVAC is another method growers use to reduce humidity. But HVACs don’t excel at humidity extraction. Though they’re able to remove some water vapor, as a side-effect of the cooling process, they’re inefficient at the task. Using HVAC for humidity reduction results in higher energy consumption and lower water extraction rates than dehumidifiers.
Drying rooms are unlike other environments and they face their own unique challenges. Not all dehumidifiers are capable of dealing with these challenges.
Most commercial dehumidifiers are designed to operate at higher temperatures. In common drying rooms temperatures these dehumidifiers won’t be able to remove sufficient amounts of water, resulting in persistent high humidity, molds and crop loss.
To achieve optimal results, growers should to use a dedicated horticultural dehumidifier, designed for the task of controlling humidity in drying rooms.
Optimal Dry Room Conditions for Cannabis
The optimal conditions for cannabis drying rooms are:
- 15-20oC (60-68oF)
- 50-60% relative humidity
- No direct light
- Air circulation to maintain uniform conditions
Maintaining these conditions ensures mold-free, homogenous, dry cannabis. Under these conditions, it should take approximately one week for buds to dry sufficiently for packaging.