After having determined the correct time of harvest for cannabis (see also "Harvesting Cannabis 101") and cut it down. It can now be hung to dry in a dry, cool, dark environment with plenty of air flow and an ambient temperature of around 20°C (68°F), as THC can be degraded from heat and light reducing the quality of the cannabis.
The drying process for cannabis is
relatively simple however if it's not done correctly the quality of the
cannabis heads can be reduced dramatically and all the hard work of
having cultivated the cannabis is wasted.
A few simple steps should always be taken before simply hanging the cannabis out to dry. Firstly taking care not to over handle the cannabis to help avoid any loss of quality from the cannabis heads, remove all of the larger branches from the cannabis plant and then continue to remove all the large shade leaves.
Once the cannabis plant has been cut down to its single branches and all the large shade leaves removed, it will look similar to the hanging cannabis pictured to the right except fresh and green as the cannabis pictured here is nearing the end of its drying time if not finished.
Take the branches and hang them as mentioned in the first paragraph of this article within a dry, cool, dark environment with plenty of air flow and an ambient temperature of around 20°C (68°F). When hanging the branches take care not to place them too close together and neither too far, as too close may attract mould and too far will cause the cannabis to dry too quickly on the outside, resulting in a loss of potency and quality of the cannabis heads.
A space kept of half a foot (approx. 150mm) or so should be plenty of space between the drying branches to avoid any risk of mould. When drying in conditions that are below the optimal environment as mentioned above, the branches should be spaced further from each other to avoid any mould, and when the conditions are above the optimal environment keep the branches closer together to avoid having them dry to quickly as previously mentioned.
The whole drying process can take anywhere from one to three weeks or so depending on the environment it's being hung to dry in and the strain of cannabis. Cannabis that has completed this drying process will look very similar to the hanging cannabis heads pictured. To test if the cannabis has dried properly take a few random branches and bend the stems till they snap at 90° or less, if the stems fail to snap then it still requires more drying time.
Once the stem is able to be snapped the cannabis heads are ready to be manicured in preparation for the curing process (see also "Manicuring Cannabis 101" & "Curing Cannabis 101").
The below formula has been worked out to help predict the expected dry weight for an indoor cannabis garden harvest. However it should strictly be used as an approximate guide only as yields vary from strain to strain, and the cannabis growing environment may not always be optimal.
Indoor Cannabis Harvest Forecast Formula:
Approx Dry Weight *per M2 = 0.001 x watts x flower light period x days in flower
Example of Cannabis Harvest Forecast Formula:
0.001 x 1000watts = 1 x 12 hours of light x 56 days = 672 grams (1.4 pounds) *per M2
It should also be noted that generally once dried correctly cannabis will be around one third (approx. 25-30%) of it's original wet weight at harvest time. This is particularly relevant with cultivating cannabis outdoors when determining an approximate for a cannabis harvest forecast. However the sun and daily weather can be unpredictable and therefore trying to determine a harvest forecast on an outdoor cannabis plant is almost impossible. Until it's harvested and given it's wet weight before being left to hang and dry.
*A square metre is approximately 10.7 ft2
written by Oz