# Preparing to harvest



## screwdriver (Feb 24, 2010)

Ahh, who am I kidding?  I don't have anything to harvest but just to prepare I use a hygrometer throughout the process.  I use several of them so the need to check calibration is important.  Knowing the rh is kind of important to me so I periodically use a wet sponge and some salt in the check.  Each one reads a little different and the cheap ones you can't calibrate but you can see how far off the needle is and you just have to remember the dial is off.

The first check I make is the full scale because it is the easiest.  I take a sponge, saturate but not dripping off, then place the hygrometer on top of it and put it in a ziplock bag.  The hardest part of the check is the wait.  The extra air within the bag needs to be saturated with the water so you can read it with the hygrometer.  I try to get most of the air out of the bag but I don't want to squeeze the water into the hygrometer.   In the picture you can see there is moisture condensing on the bag so the extra air is saturated.  The hygrometer is off for the full scale and only reads 90%.  Thats why I put +10 on the dial.  I add 10 to what the dial reads when using. 




The next test I use is to check it at 75%.  I use a mixture of salt and water.  I put about a tablespoon of salt in a shotglass and add a little water.  Just enough to moisten not to make it soupy.  I usually fail at that and have to add more salt. Then place it in a jar with the hygrometer.  Again, the hard part is the wait. Patience is needed for this because there is a larger air volume in the jar that has to equalize the rh.  This will take hours so I will leave like this overnight and check in the morning.



All of this should be done at 70 degrees which is what the temperature happens to be in my house.  

Another way I check my small analog hygrometers is with the gel. The range should be between 70 - 74%.  I tape the hygrometer over the top the container.  This particular hygrometer reads about 5 points over.  If I put this in a jar to monitor something I would want to see it read in the range of 70-75%.  I'll put a -5 on the dial to remind me to subtract 5 from the reading.  Thats easier for me then to pop the lens cover off and try to stick the needle in the correct place.


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## screwdriver (Feb 27, 2010)

Here is one of my favorite hygrometers.  One of the more accurate analogs.
I like keeping my stuff between 65% and 70% rh and these fluff jars I use have a wide opening and can hold between 1 and 4 ounces depending on the type of tobacco.


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## BBFan (Feb 27, 2010)

Hey Screwdriver-

Interesting.  Thanks.

So the salt trick..... why does that produce 75% humidity?  How can you be sure that you have created a precise (or nearly precise) baseline.

Oh, by the way, not too many of us here grow tobacco


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## screwdriver (Feb 27, 2010)

I don't know the magic behind the salt but it seems to absorb moisture.  I assume it finds a balance with air at 75%rh.  The correct temperature is also important.  This is really a standard practice if you search the internet on calibrating a hygrometer.

I don't grow tobacco. Not enough room in my backyard and I really, really like my grass.  Also, I don't have enough room or light in my cabinet to produce anything.  It much easier for me to buy my tobacco even with the new taxes.

Tobacco is just another plant that is smoked and the methods of harvest and preparation and storage can be directly applied to other smokables.


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