Drying Cannabis with Dehumidifiers

Rambo November 21, 2016 2
Drying Cannabis with Dehumidifiers


I’ve heard different opinions about drying cannabis with dehumidifiers. Some say it really helps the drying process and others say “don’t use them, they will ruin your harvest and turn your buds to dust”. What are your thoughts on using a dehumidifier to dry freshly harvested buds?


Dehumidifiers are a great way to speed up and control the drying process. Like many growers, I have been using dehumidifiers for many years. That being said, there is a right way and a wrong way to use any tool. Dehumidifiers are designed to lower the humidity but there are many factors that will determine how much humidity needs to be removed. Here are some things to consider when drying cannabis.

  • How full of plants is the drying room.
  • What is the humidity of the air outside your drying room.
  • What is the temperature in the drying room.
  • Were the buds wet from rain or dew when they were harvested.
  • Were the buds stripped of leaves or removed from branches.
  • Were the buds processed through a wet trim machine.

Tips on Harvesting Cannabis

I prefer to harvest large plants in 3 stages. In the first I take in all the largest buds from the tops of the plants. These buds usually ripen first and are most susceptible to mold since the buds are very dense. I try to cut these in 2 to 3 foot sections.

The lower branches are now exposed to additional light which now helps them ripen. When ready these branches are taken in a second round of harvesting. These branches are often shorter but still in cola form.

The very small flowers from the plants interior are now exposed and will finish ripening. These are usually to small to leave on the stems but can be cut one bud at a time.

It should be noted that from the time I take the first cola, as much as month may pass before I harvest the last bud from that plant. Some strains come down best this way, while others can be harvested all at once.

Tips on Drying Cannabis

When I bring buds into a drying room I try to fill it as completely as possible. By doing so, all of the buds will dry at relatively the same rate. If for any reason you bring freshly harvested buds into a room that has been drying for a while, this new moisture will bring up the humidity of the room and will partially re-hydrate the drying cannabis. This throws a monkey wrench in the drying process and should be avoided if possible.

There are two basic ways to harvest and dry your buds.

The first options is to line dry or hang the buds. This means the flowers are left on the branches and hung upside down in 1 to 3 foot sections. I prefer this method because the branches store moisture which is gradually sucked up by the drying buds. This slows the drying process and makes it easier to avoid over drying the buds.

The second method is screen drying buds. The flowers are removed from the branches while harvesting and since they can’t really be hung to dry, they are dried on screens instead. Screen drying is less forgiving and more susceptible to over drying. Since the stem is no longer attached to the bud, it can’t act as a moisture reservoir if the buds over dry. While I don’t think this method is ideal, if you are using a wet harvesting machine like the satellite, twister or centurion, you don’t really have any other options.

When I fill a drying room, I first run the dehumidifiers full blast and leave them on overnight. By morning the flowers will have a bit of wilt and the drying process is in motion. I then monitor the dry room closely and may turn them up or down depending on how quickly the bud is drying and how warm the room is getting. I also use fans to circulate air and keep the temperature and humidity even throughout the drying room.

The goal is to slowly dry the buds while staying ahead of any possible mold problems. If the outside temperature is warm I try to turn the dehumidifiers off and let fresh air flow through the room for a few hours each day. I do my best to hold the room at around 70F (cooler at night) and at about 40-45% RH.

By the third or fourth day, the buds should begin the feel a little crisp at the edges but if you try to bend the stem it will bend and not crack or break. At this point I “sweat” the room. To do this I turn off all the fans and dehumidifiers and seal the room overnight. By the next morning the moisture from the stems will have wicked into the flowers. The stems will be drier but the flowers will have re-hydrated some. I then turn the dehumidifiers and circulation fans back on but at a lower setting. The worst threat of mold is mostly gone since a great deal of the water has been removed. I repeat this process 3 to 4 times until the stems begin to crack when bent. From harvest to this point is ideally 7 to 10 days. The branches of buds can now be processed or stored.

If you plan to store the buds and manicure them gradually, these branches can be stored in large plastic Rubbermaid totes with tight fitting lids. These will keep nicely in a cool dry place but should be monitored for at least a week. If excess moisture remains it will sweat into all the plant material in the tote and may potentially ruin the buds.

You can also remove the buds from the stems and store them in this same kind of tote. Either way, the curing process takes place in the totes and they will keep nicely until needed. I personally find that flowers keep much better if stored on their stems without having been manicured. I avoid trimming until just prior to use and believe this preserves the flowers nose and color of the buds. I should point out that not everyone is of this belief.

Take your time, look for 7-10 days of slow drying before placing buds into sealed storage and always monitor the buds for a few weeks after storing.

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  1. Tracy December 8, 2016 at 12:53 pm -

    My plants are in the buding room ! The tops of plant is changing from green to a army green but still Cristals & sticky ? Rest of plant is green & buding ?

    • Rambo December 8, 2016 at 4:25 pm -

      I don’t understand what your question is or what this has to do with drying cannabis with dehumidifiers. If you have a question please be clear and ask in the appropriate place. Thanks!