Off-grid drying and curing

[cbdhemp808]

I'm growing off-grid in Hawaii in a tropical, warm, wet climate. I would like to build a small, closet-size drying room, and follow Ed Rosenthal's recommendations for drying and curing, to produce the best end product, maximizing terpene retention. Here are the parameters according to Ed's article:

Drying, 1-3 weeks
• terpenes start evaporating at 68º F (myrcene... one I would especially like to retain!)
• fungus and bacteria start germinating at temperatures between 50 and 70° F
• temperature about 68° F
• humidity 46-52%
• use oscillating fans
• dim light

Curing, 10-30 days
• temperature 65-70° F
• humidity 50-55%
• use oscillating fans
• dim light

Here are my parameters:

• outdoor, greenhouse grow; perpetual grow
• producing small buds
• very mold-prone environment
• off-grid, small solar power system (42 amps at 12 VDC = 500 watts; 1500 watt inverter)
• don't want to use a generator
• daytime ambient temperature between ~75 and 85° F (usually high 70s to 80°)
• nighttime ambient temperature between ~65 and 72° F (usually around 70°)
• closet-size drying room to be constructed
• have purchased a small dehumidifier: Pohl Schmitt, 2200 Cubic Feet (225 sq ft), removes 10 fl. oz. water/day max.
• very small budget

I would like to include the dehum and possibly an air purifier in the system. I'm stumped as to how to bring the temperature down to 68° and at the same time provide dehum and purification: not only because of the elec. power limitations, but also I understand that the dehum will generate heat, and an affordable, small air conditioner will generate moisture (evaporative system).

I'm looking for any advice. I'm thinking I'll need to get real creative on this – maybe it's not possible. One thought is to somehow take advantage of the overnight air temps, and insulate the room heavily to retain that coolness during the day. Another thought is to create some kind of heat exchange chamber (think plastic trash can) that brings in room air and emits cool, dry air.

Everything needs to be minimal power consumption, because the solar power system needs to still power the house, meaning primarily refrigeration and satellite internet (the two most power-consuming). During sunny days, the system is at max output, and there is plenty of extra power.

One question: Is it even possible to preserve myrcene in this situation?

 

[Braddah Waiheesohai]

It's pretty hard to get a great dry and cure in Hawaii without air conditioning.

If you run a fridge you could try fridge drying. There's a few propane fridges floating around that can be found for cheap.

Have any friends that live high up on one of the volcanoes? Once you get above 5,500 feet the temps and humidity are much more hospitable to terp preservation.

 

[cbdhemp808]

@Braddah Waiheesohai Thanks, brah... Your reply has sent me in the direction of looking at fridge drying, specifically the @DrZiggy method, or a variation of it, which has a long thread here on 420. I like the sound of what @Green Dreams posted, about buds in cardboard US post flat-rate boxes (I suppose paper grocery bags would work, too), and using an InkBird to keep the fridge at 38°...

@Green Dreams :

I was able to fill the fridge with approximately 70% of my "Grade-A" (i.e. best) colas/tops within the boxes. The boxes are directly stacked on top of each other. Fridge temperature is controlled by an InkBird temp/hum controller and is set for 38 degrees F, with a differential of 3 degrees F. Humidity is currently hovering between 60% and 70%. I will not open the fridge for at least 2 weeks. This fridge is a non-frost free model, however the freezer element was developing a layer of ice on the coils, thus I am relatively confident that it will serve the intended purpose of removing humidity from fridge compartment air, albeit without the self-defrosting convenience.

At first I was confused about this, i.e. where is the moisture going when it leaves the buds? but I understand the freezer element inside the fridge is absorbing the moisture and turning it into ice... makes sense. We are currently using a mini fridge in our kitchen – one of these dedicated to drying buds would work, because it has a freezer element up top, and is low power consumption. Maybe I could set the InkBird for a bit higher temp, maybe 45°, to use less power.

Regarding drying and curing ~ for the drying step in this fridge method, it seems that humidity isn't really a factor, since the temperature is below 50° which prevents mold and bacteria from developing. Or, is it the case that the lower the temperature, the less humidity is in the fridge – meaning that a 38° environment will have less humidity than a 45° environment? But it seems that, as long as mold is being prohibited due to cold temperature, we would want a higher temperature (e.g. 45°), so that moisture will leave the buds more quickly, thus causing higher humidity in the fridge... before, that is, it turns to ice. @GratefulBud says under 45°.

And, I just found this post by @420giirl ... seems she has dialed in the mini fridge technique! very cool, wink wink.

Regarding "washing", in my situation, maybe I could do this... harvest in the early morning before sunrise when terps are at their peak and outdoor temperature is at its lowest, hang the buds immediately after harvest in a sealed closet with an air purifier running, and oscillating fan, and spray them down with a peroxide solution (same one I use to prohibit mold during flowering, 6 fl. oz. -or- 12 tbps 3% peroxide in 1/2 gal. distilled water). When dry, bag/box them up (in the closet) and place in the mini fridge. The mini fridge could live in this closet. Hence my "drying room" has become a washing and fridge room. My little dehum could be running in there, too, for the wash/dry step.

So, what then about curing?

 

[Braddah Waiheesohai]

@Braddah Waiheesohai Thanks, brah... Your reply has sent me in the direction of looking at fridge drying, specifically the @DrZiggy method, or a variation of it, which has a long thread here on 420. I like the sound of what @Green Dreams posted, about buds in cardboard US post flat-rate boxes (I suppose paper grocery bags would work, too), and using an InkBird to keep the fridge at 38°...

@Green Dreams :


At first I was confused about this, i.e. where is the moisture going when it leaves the buds? but I understand the freezer element inside the fridge is absorbing the moisture and turning it into ice... makes sense. We are currently using a mini fridge in our kitchen – one of these dedicated to drying buds would work, because it has a freezer element up top, and is low power consumption. Maybe I could set the InkBird for a bit higher temp, maybe 45°, to use less power.

Regarding drying and curing ~ for the drying step in this fridge method, it seems that humidity isn't really a factor, since the temperature is below 50° which prevents mold and bacteria from developing. Or, is it the case that the lower the temperature, the less humidity is in the fridge – meaning that a 38° environment will have less humidity than a 45° environment? But it seems that, as long as mold is being prohibited due to cold temperature, we would want a higher temperature (e.g. 45°), so that moisture will leave the buds more quickly, thus causing higher humidity in the fridge... before, that is, it turns to ice. @GratefulBud says under 45°.

And, I just found this post by @420giirl ... seems she has dialed in the mini fridge technique! very cool, wink wink.

Regarding "washing", in my situation, maybe I could do this... harvest in the early morning before sunrise when terps are at their peak and outdoor temperature is at its lowest, hang the buds immediately after harvest in a sealed closet with an air purifier running, and oscillating fan, and spray them down with a peroxide solution (same one I use to prohibit mold during flowering, 6 fl. oz. -or- 12 tbps 3% peroxide in 1/2 gal. distilled water). When dry, bag/box them up (in the closet) and place in the mini fridge. The mini fridge could live in this closet. Hence my "drying room" has become a washing and fridge room. My little dehum could be running in there, too, for the wash/dry step.

So, what then about curing?

Putting curing jars in a cooler / ice chest in a cool place in the house works well. You can add a plastic bottle or two of frozen water to the cooler to keep temps down even further. That creates a perfect cool dark environment for curing and is cheap and easy to maintain off grid.

 

[GratefulBud]

And, I just found this post by @420giirl ... seems she has dialed in the mini fridge technique! very cool, wink wink.

Given the high humidity in your area I would say the fridge dry is a good choice. People think the inside of refrigerators are humid - they are really not (depending on the fridge and what you have inside).

 

[GratefulBud]

So cool story if I may. Back in the early 80's there were some great Hawaiian strains going around. Maui Wowie was one I remember and another was called Puna Buds. I was leaving a 7-Eleven at about 3am and saw a baggie on the ground next to my car. I picked it up and to my delight found about a half oz of Puna Buds! Small lime green buds with bright orange hairs. Tight buds - about the size of a quarter and shaped like little footballs. REALLY GOOD STUFF!

 

[cbdhemp808]

@GratefulBud I am drying some MW today, but quick-and-dirty style using a food dehydrator heater/fan base, and a small fan, in the oven. I vaped some Kush last night from this style drying, and it was kick ass. But, I sure do want to preserve terps and flavor, so... gearing up for mini fridge method for next harvest. Growers in Hawaii made a lot of money in the '80s – it's how a lot of homesteaders got started.

 

[VeigarMid]

Interesting to find this thread. I've been struggling with these exact same problems myself haha. Drying on the big island can be challenging because it's always pretty hot and humid. Also, a lot of places out here aren't really build for air conditioning or closed spaces, and the cost of air conditioning is probably prohibitive for most people living out here.

I tried drying in the air, and it does work, but the flavor and taste kind of disappears. Some of my buds in the past have almost ended up smelling and tasting a bit like cigarettes or something, just not that classic cannabis smell. It's from bad drying procedure...

So recently I have also been attempting some fridge drying. I have a small mini fridge that does generate some frost on the top but it's manageable. I load buds up into individual paper bags and stow them in the fridge with labels. I've also got a bunch of larger desiccant packs in the fridge to help soak up moisture. I've ran into mold issues a couple times in the past with this method, like in the fridge as they are drying. The causes tend to be too much moisture right on top of the buds, or the buds clumping together. I originally tried putting fresh buds into clean jars with pantyhose over the top but it made the jars sweat quite badly and they quickly formed mold. Paper bags work much better, but mold can still sometimes form if the buds get really clumped as they like to do. So now I am shaking the bags lightly once or twice a day, at first, just to keep them fresh. The other issue I've ran into sometimes is staggered harvests, when some plants have to come down early due to bud rot infection (my number 1 issue by far!). If you toss in fresh harvested plants on top of already drying ones it can reintroduce all the moisture to them and cause mold.

I'd love to hear what you eventually decided on doing though! It's been a big issue of mine haha

 

[cbdhemp808]

Hey @VeigarMid and welcome to the forum!

Your reply is very timely!

I decided to skip the mini fridge idea and spring for a portable AC unit. I'm gearing up to build a kick ass little closet-size drying/curing room, with racks for wet trimmed buds. I have a small dehum already, and the AC unit is on the way and is a dry-type unit – it actually pulls moisture out of the air as part of the cooling process.

Cooling the small space shouldn't require a whole lot of power. However, the AC does draw a lot of power, so that's where I'm going to use some automated controls, to make best use of my limited solar power. I'm planning on using Inkbirds to monitor temperature and humidity, and power the AC unit and dehum.

I am also going to set up a custom sensor to detect the available power, and then automatically turn on power to the Inkbird(s). So, the automation will be 2-stage – the Inkbird(s) running the equipment won't get power unless there is sufficient solar power.

The room will be air tight and heavily insulated on the inside. My general goal is to keep the temperature at about 65° or lower all the time while the buds are drying/curing, and humidity at 50%. During the day with ample power, I'll push the temperature lower, so that at night when we're running off battery power, the temp won't get above 65°. It's possible the temp will get above 68° sometimes, but my intention is to minimize this. (68° being the threshold for terpene evaporation.)

There are some design details to work out, but I have located all the parts I need to make this happen.

 

[VeigarMid]

Wow, well good luck! this is the kind of thing I definitely did NOT want to get into, but it seems almost unavoidable here huh! My power bill is already creeping up towards $300 a month, I couldn't imagine what even a small AC unit would add over here! it makes a lot more sense to run such a system off solar.

It's also timely for me. I had to cut down a plant a bit early today because it was getting attacked by budrot and budworms. That's also around the time I start looking around the internet for all the tidbits I missed on how to dry in humid areas! haha

 

[GratefulBud]

Hey @VeigarMid and welcome to the forum!

Your reply is very timely!

I decided to skip the mini fridge idea and spring for a portable AC unit. I'm gearing up to build a kick ass little closet-size drying/curing room, with racks for wet trimmed buds. I have a small dehum already, and the AC unit is on the way and is a dry-type unit – it actually pulls moisture out of the air as part of the cooling process.

Cooling the small space shouldn't require a whole lot of power. However, the AC does draw a lot of power, so that's where I'm going to use some automated controls, to make best use of my limited solar power. I'm planning on using Inkbirds to monitor temperature and humidity, and power the AC unit and dehum.

I am also going to set up a custom sensor to detect the available power, and then automatically turn on power to the Inkbird(s). So, the automation will be 2-stage – the Inkbird(s) running the equipment won't get power unless there is sufficient solar power.

The room will be air tight and heavily insulated on the inside. My general goal is to keep the temperature at about 65° or lower all the time while the buds are drying/curing, and humidity at 50%. During the day with ample power, I'll push the temperature lower, so that at night when we're running off battery power, the temp won't get above 65°. It's possible the temp will get above 68° sometimes, but my intention is to minimize this. (68° being the threshold for terpene evaporation.)

There are some design details to work out, but I have located all the parts I need to make this happen.

Awesome!

I read somewhere that ideal dry room is 62%RH @ 62˚F with a small fan for air movement. Not sure if that is accurate but seemed logical. Should be dry in about 7-10 days.

Good luck!

 

[cbdhemp808]

Wow, well good luck! this is the kind of thing I definitely did NOT want to get into, but it seems almost unavoidable here huh! My power bill is already creeping up towards $300 a month, I couldn't imagine what even a small AC unit would add over here! it makes a lot more sense to run such a system off solar.

I hear you. But the size of the room is key... very small closet-size space, not a lot of power required to cool it down. For me to do this on my small solar power system, I need to do some magic in terms of sensors, etc. That's what makes it possible. The AC I bought is the lowest-power of its kind, 8000 BTU. I think about 8 amps.

When the sun is out, I have used paper bags in the greenhouse, and that works well. Of course nothing like cold drying.

It's also timely for me. I had to cut down a plant a bit early today because it was getting attacked by budrot and budworms. That's also around the time I start looking around the internet for all the tidbits I missed on how to dry in humid areas! haha

I am also battling the bud rot... recently harvested 2 kush plants and lost 1/2 to 1/3 to bud rot... should have harvested earlier. Also harvested a maui wowie at the same time... it had only a little bud rot. I've got a blue dream ready, and keeping a close eye on it today. I spray peroxide solution on the whole plant and buds – 6 fl oz 3% peroxide in 1/2 gal water (6 fl oz is 12 tbs).

 

[cbdhemp808]

Awesome!

I read somewhere that ideal dry room is 62%RH @ 62˚F with a small fan for air movement. Not sure if that is accurate but seemed logical. Should be dry in about 7-10 days.

Good luck!

Thanks. I'm following the Rosenthal method for small scale drying & curing. He says humidity above 55% will allow fungi and bacteria to grow on wet material. Maybe 62%RH for the curing would be good. I will definitely have an oscillating fan in there.

 

[VeigarMid]

I am also battling the bud rot... recently harvested 2 kush plants and lost 1/2 to 1/3 to bud rot... should have harvested earlier. Also harvested a maui wowie at the same time... it had only a little bud rot. I've got a blue dream ready, and keeping a close eye on it today. I spray peroxide solution on the whole plant and buds – 6 fl oz 3% peroxide in 1/2 gal water (6 fl oz is 12 tbs).

Yeah, I had a guy at the growshop swear that White Widow from 420 was very good in the climate here so that's what I've been growing. What's funny is one of the plants has had bud rot issues, PM all over the leaves etc and it got to the point where I decided to cut 2 or 3 weeks early just so it wouldn't get worse. I know from experience that you end up losing more like half if you wait too long, as you say.. But it's sister, sitting right next to it, has had not one spot of rot, mold, PM, anything! it's baffling. I topped the resilient one and not the one that had issues, and one sat in a tray with overflow sometimes and the other not but that's it. I can't tell if its resilience or just sheer luck but its fine now!


I wonder if spraying your plants has an negative effect even though its got H202 in it, just cuz it keeps them wet?

 

[SmokingWings]

Sounds like it should all fall into place. A lot of planning and well organized A couple of things caught my attention.

• fungus and bacteria start germinating at temperatures between 50 and 70° F

Started looking into this sort of thing several years ago as it related to mildew, molds and bud rot and I keep coming across 40 F. We can get mold, etc in a fridge even though they are set at the upper 30s but they will be growing slower. Then they start growing a lot faster at 50 but I found enough info to make me keep the lower temp in my own plans.

looking at fridge drying, specifically the @DrZiggy method, or a variation of it, which has a long thread here on 420. I like the sound of what @Green Dreams posted, about buds in cardboard US post flat-rate boxes (I suppose paper grocery bags would work, too), and using an InkBird to keep the fridge at 38°...

I have not tried the cardboard box but have used the brown paper bags. From what others have mentioned the moisture leaves the buds and stems and the paper in the bags or boxes traps it. Then the air movement in the fridge removes it from the paper. Slow process but the results are worth it.

I remember asking about this one time and some of the members who had already started using the method did mention that the fridge should be a frost-free one that has the fan the moves the air from the freezer to the fridge otherwise it really slows down the drying. A few said it could stall the drying and did not recommend anything but a frost-free. The bad part is the fan adds to the draw on the electrical system.

Not sure how fast frost would build up in your environment and that would have to be kept in mind with a propane fridge. Not sure if any of them are made with a fan. Somehow getting around the frost-free fan issue and they are perfect for someone living off the grid.

 

[cbdhemp808]

Sounds like it should all fall into place. A lot of planning and well organized A couple of things caught my attention.

Thanks. I think maybe you were looking at an older post of mine. Here is my latest plan... Off-grid drying and curing

 

[cbdhemp808]

Yeah, I had a guy at the growshop swear that White Widow from 420 was very good in the climate here so that's what I've been growing. What's funny is one of the plants has had bud rot issues, PM all over the leaves etc and it got to the point where I decided to cut 2 or 3 weeks early just so it wouldn't get worse. I know from experience that you end up losing more like half if you wait too long, as you say.. But it's sister, sitting right next to it, has had not one spot of rot, mold, PM, anything! it's baffling. I topped the resilient one and not the one that had issues, and one sat in a tray with overflow sometimes and the other not but that's it. I can't tell if its resilience or just sheer luck but its fine now!

Yes, I have heard that about WW as well, but haven't grown it. There are many varieties that are mold resistant. I think sativa-dominant is usually more resistant than indica-dominant, generally speaking.

Did you grow the WW from seed? If so, that could explain why one did better than another... because of phenotypic differences.

WW was created from a Brazilian sativa and an Indian indica. Apparently, some phenos are more sativa-leaning, which could explain why some plants will be more mold resistant. The strain is listed as 60% sativa, so perhaps the sativa-leaning pheno is typical, and sometimes some indica characteristic are expressed, and hence some are more vulnerable to bud rot.

I'm currently growing a Gelato cross that is supposed to be very mold resistant, and it's 70% indica. So far, I'm not seeing much mold at all. So, I find it interesting that it's an indica-dominant plant.

I wonder if spraying your plants has an negative effect even though its got H202 in it, just cuz it keeps them wet?

I considered that, but I don't think it's an issue. My sense is that, as long as the wetness is there, so is the peroxide. My flowering plants are in a greenhouse that gets good warmth and air flow, so evaporation is fairly quick. The plants aren't getting rained on. The humidity in the air, and all the mold spores, is what causes the mold on leaves and the bud rot.

happy growing!

 

[TorturedSoul]

Someone once gave me a quantity of bud that had been done the "low and slow" way in a refrigerator. It wasn't cured; was still as green as could be (IOW, the chlorophyll hadn't been converted into sugars).

The AC I bought is the lowest-power of its kind, 8000 BTU. I think about 8 amps.

Are you talking about a portable type? Because window units are available in 5,000 BTU versions, and they are typically 3.00 to 4.35 amp devices, depending on their efficiency. They're also generally cheaper than the portable ones. Of course, you have to have a window (or a saw ).

I hope you find a way. The dry/cure is as important as, well, everything else.

 

[cbdhemp808]

RE: A/C unit

Are you talking about a portable type? Because window units are available in 5,000 BTU versions, and they are typically 3.00 to 4.35 amp devices, depending on their efficiency. They're also generally cheaper than the portable ones. Of course, you have to have a window (or a saw ).

I hope you find a way. The dry/cure is as important as, well, everything else.

Thanks. I'm talking about a free standing portable AC. The window kind didn't make sense to me, because I don't want any possibility of outside air coming in. Anyway, I don't know much about AC... never bought one before. But I figure my very small drying room size will be energy efficient to keep cool with this fairly compact unit that I ordered.

I'm very much looking forward to proper dry/cure. My buds are turning out plenty potent, but I def want the terps as well.

 

[SmokingWings]

Thanks. I think maybe you were looking at an older post of mine. Here is my latest plan... Off-grid drying and curing

Interesting .

I was pulling the quoted text from the first msg in this thread which is the one you linked to. Did not know about an earlier plan.