Diy Dry Box

I assume you are going to want moving air to prevent mold.
 
Maybe add a desktop fan as an exhaust?

 

Fishing line, cardboard box.
 
 
That's all you need, if you're making your own.  
 
 
I have a literal 'wall', of thirty or forty boxes, just like these.
 
 
 Just cut a few breathing holes on all four sides of the box. More holes if you're in a humid environment, fewer and smaller holes if it's very dry where your boxes will be placed. Then, almost as if you're sewing, punch holes and string the line through one side of the top, leading to the opposite side, creating a series of parallel lines for hanging. Leaf can go on the floor of the box below, which can be helpful in preventing the humidity from dropping too fast in an overly-dry environment (or it's just useful if you have no where else to dry them), and the buds get hung.
 
 
You don't want the buds resting on, or even against the box. The oils responsible for flavor, some of which even behave as solvents and can strip and carry cannabinoids (notice when your hands feel greasy/sticky after handling buds?) can and will seep into the absorbent cardboard, resulting in their loss, that and with all that contact you can lose whole glands as the bud dries, and you'll end up with flat, or worse, moldy buds if you don't rotate often enough.
 
 
 Hanging eliminates ALL of that, it saves potency, and it leaves you with a better looking finished product. 

 

I have seen grow boxes with one fan and it seems to do fine but I would add two just to make sure.

 

 
 Temperature and humidity are different things
 
 
  If you're on a budget, you can buy a non-digital $6 - $10 hygrometer-thermometer combination, that lets you know both the temperature and humidity. If you have a few extra bucks, a digital combo can be more accurate, they start around $20.
 
 
 I don't use one myself, not in the dry boxes anyhow (the batteries in the digital combo I keep in my main bloom room, have actually been dead for about a year, too, come to think of it ), but I've been doing this a while  I know my buds will dry faster during the dry season, late fall and winter, so I arrange the boxes to close off excess holes that are useful for the required aeration and circulation during the humid or muggy (now) season.
 
 
Regardless what your meters say, you still need to keep an eye on your buds... if they're drying out too thoroughly in under 5 days, the humidity is likely too low. But if by four or five days they've gone from feeling firm, to feeling somewhat soggy to the touch, you need to do something about circulation and lowering the humidity inside the box. This could just require extra 'breathing' holes, or the addition of a small fan to consistently pull out moist air, and force in more-dry air.
 Under normal circumstances the humidity in your box should (obviously ) be higher than the outside room. In rare cases, sometimes with larger crops or just in certain climates, dehumidifiers can be required to keep the surrounding room dry enough. If it's muggy, and it's just as humid outside the box as inside, there's a good chance you'll see mold.
 
 
 
 As far as numbers go... ideally, depending on your personal preference and the qualities of the bud (which you'll learn to tweak accordingly over time), you want a humidity between 45% to 55%,  50% to 60%..... much lower or higher would be leaving the 'comfort zone' you're looking for. Temperature wise, keep the boxes above 55 f and below 70 f if possible! Drying should take no less than 8 or 9 days, or better, at least two weeks. Any faster, or if it dries too much before jarring, and you risk losing much of the enzyme action that occurs during the cure.
 
 
 
 Hope this helps.