Cultivators often don’t have a dedicated space to dry their medical cannabis. I can maintain ideal conditions for drying in my room, except for the darkness aspect (I’m never without plants). Drying cannabis needs to be dark so we can deactivate the chloroplasts (tastes bad) in the plant. Here, we’ll go through the steps to create your own expandable and collapsible drying cabinet, all for less than $50!
Step 1: Gather the materials you need as seen in this picture. I purchased these fans cheaply on amazon and 62 CFM (cubic feet per minute) is plenty of airflow for our small 2 CF containers. I believe the speed controller is a necessity, but we’ll come back to that later. You might also grab a sharpie, screwdriver, and/or small drill for layout and assembly. These fans came with the needed fasteners.
Step 2: We want to create airflow and will need to create an intake and exhaust port. I’ve used a sharpie here to trace and layout where/how I intend to make my cuts. The important part here is to ensure that your intake is at least a big as your exhaust port. My exhaust port is a 4.5″ circle, or 15.9 square inches.
Step 3: Once satisfied with the design, cut your ports and install your fan and controller. Your fan should be pulling air out of the container.
Step 4: Drop in a rack (to encourage airflow all around your cannabis) and assemble.
Viola! Within an hour you have a basic drying box. However, I know you’re an overachiever and will have a big harvest, so we probably need more room. Set this aside and let’s make an expansion, shall we?
Expansion Step 1: Turn a second container upside down and mark out some ports on the bottom of the container. Remember to meet or exceed the size of your exhaust port.
Expansion Step 2: Cut the bottom of the container per your layout. Then place the new lid under the container and trace the ports to match.
Expansion Step 3: Cut the ports in the lid and then assemble the full unit. Drop in the racks, stack the containers in the right order and you’ve just doubled your drying capacity! Repeat the Expansion Steps to further expand your cabinet to match your needs.
Be creative; a clever DIYer could rig the top box with a carbon filter to build in a solution for smell. I have a dark corner so I’m less worries about light infiltration, but you can take extra steps to really light-proof this box nicely. At 50+ CFM, this fan has the capacity for more containers than you can safely stack. I mentioned that it can collapse as well, right? Take the rig apart and nest the containers inside each other for ease of storage.
- This fan/controller has a short power cord. However, it only draws 8watts so an extension cord is a fine solution.
- I only used 1 fan in this kit but I ordered 2. I’m keeping the second for a backup because airflow is crucial.
- The purpose of the fan is to exhaust humid air and replace with the dry (<50% Rh) air from your larger area. When the buds are first set to dry they will put off a lot of moisture, after the first few days this slows. This is what the controller is for. After the first few days slow the air down a bit so that the drying will slow as well. You need to provide time for the moisture to wick from the inside of your buds to the outside where they out-gas. A schedule like this will work, but you may need to fine tune it to your needs and ability to control humidity:
- Day 1: Controller/fan at full speed @ 50% Rh
- Day 2: Full speed @ 50% Rh
- Day 3: 3/4 speed @ 50% Rh
- Day 4: 3/4 speed @ 50% Rh
- Day 5: 1/2 speed @ 55% Rh
- Day 6: 1/2 speed @ 55% Rh
- Days 7-10: 1/4 speed @ 60% Rh
- I prefer not to stack wet buds on racks because the trichomes are so fragile when wet. Hanging (without touching anything) is the best. However, due to space limitations I’ll make due with this and be extra gentle.
- Stack buds (still on stem) in a cross-hatch pattern so that air can flow through the stack. This will promote consistent drying.
- Depending on the performance of the drying cabinet you’ve made, you may need to rotate the order of the cabinets from time to time. The bottom-most containers will dry faster than the top because moisture accumulates (by design) as the air traverses the containers. I compensate for this by putting the biggest buds in the bottom container and the smallest material (which dries faster) near the top.
- You will want to fiddle with the cannabis as little as possible (so you don’t dislodge/destroy trichomes) so resist the urge to sift through he contents if you can – especially once you gain confidence in your setup and techniques.
Happy Harvests!
— The Lit Farmer —