After harvesting, industrial hemp has to be dried to get it ready for industrial use. Drying involves hanging or spreading out the hemp so that it can lose water and moisture. It can either be done by hand or by a machine when the operation is commercialized. Below we explain how to dry hemp by hand.
Before industrial hemp is dried, it is first harvested. To tell whether industrial hemp is ready for harvest you need to check two things: fiber volume and quality, and the yield and quality of seeds.
Hemp seeds start to mature (turn from green to brown) from the bottom of the seed head upwards. Don’t wait too long after the seeds mature as they may start to dry and shatter.
DIY Hemp Drying Room
Interested in building your own hemp drying room? Here’s a DIY how-to video from Greenshine Farmers.
Harvesting industrial hemp
Once the industrial hemp is mature the next thing is to harvest it prepare for drying.
Hemp flowers are easy to bruise especially when wet, wear hand gloves to protect your hands. You will also need heavy-duty shears, totes for storage and (wheelbarrows) for transport. Once cut, transport the hemp to a drying room that should have been prepared in advance.
The Drying Process
Industrial hemp needs to be dried as soon as it is harvested and the process should take the shortest time possible. Drying it over an extended period will increase the moisture content and affect quality.
Drying industrial hemp by hand
The first thing to do is to prepare the drying room.
Industrial hemp can be dried in barns, garages or anywhere else where environmental factors can be controlled. There needs to be sufficient movement of air. When the circulation of air is poor air fans come in handy to help out. The more the fans the better, this pushes wet air from the plants and replaces it with dry air to speed up the drying process. This is called wicking. However, you should be careful not to overdo it.
The next thing is to dry the industrial hemp. You can choose to hang dry or use a screen. If you are hang drying you will need to prepare hanging lines in your drying room and have pegs for hanging the stems. The room should be covered and well ventilated. The hanging lines or screen are arranged in rows with adequate spacing between the rows to prevent congestion.
For hang drying, cut longer stems to give enough room for hanging the stalks on the hanging lines. The main is cut into a “checkmark”- which makes it easier to hang the hemp.
If you are screen drying you can cut smaller sections to lay flat on your screen.
Regardless of where you dry your industrial hemp make sure that there is no dust. When too much dust accumulates on the plant it may affect the overall quality of the industrial hemp. If you are using a garage or anywhere with lots of dust clean it out thoroughly before setting up the drying room.
Drying Industrial Hemp Seeds
Heated air dryers can be used to dry industrial hemp seeds which are put in a bin. You will need to monitor the dryer temperatures as overheating may cause the hemp seeds to turn yellow and reduce the quality of the hemp. Fans can also be used to enhance the drying process. You will also need to turn the seeds to ensure even drying and reduce chances of mold.
Optimum humidity levels for drying industrial hemp
You should aim for a relative humidity of 10%-12%. If the industrial hemp is to be stored for a long time you should aim for 8%.
If humidity levels are high it may be necessary to invest in dehumidifiers. It’s best to place the dehumidifiers near the ceiling where warm air accumulates.
How to Tell If Industrial Hemp Is Completely Dried Out
You need to check the amount of moisture in the plants to know if they are completely dried out. The simplest way to go about this is to use a humidity probe (you can buy one on Amazon for about $30). You are looking for relative humidity that’s between 10%-12%.
An old school way to go about this is to carry out a stalk-bend-test. Try to bend the stalks, if they fold easily it means that there is still a lot of moisture. If the stalk snaps, the hemp is well dried out.
Once you are confident that your industrial hemp is dry, the next thing is to store it.