Humidity during the dark period

I noticed the max humidity reading on my hygrometer got up to 77% last night. During the day when the light is on and drying out the air it stays around 55 to 60%. I am running a fan 24/7. Should I turn off the humidifier at night? Will it hurt the plant to have lower humidity during the dark period? I am running 18/6. I am in the beginning of the veg stage at 16 days above soil.

I would shut it off at night if it gets that high. You want the same rh 24/7 according to the vpd chart…or at least close. Use the vpd chart and keep it close. That will really tell you if you need to shut it off or not.

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I found a chart and since my temps are pretty steady at 70 to 71 degrees at night with the light off I would need to maintain 60 to 65% humidity. I will try turning off the humidifier tonight and see how low it gets but I am guessing it will go down to around 50%.

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Your light lowers rh some during the day so at night it might be right where you need it.

Humidity doesn’t really matter during the vegetative stage but it matter when you start getting big buds as this can give you Bud rot if your humidity is too high

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One thing that sucks is my whole house is too humid now. It is 64% in my bedroom which is pretty far from the grow room in another part of the house. It has been just the right temp outside for the past few weeks (50 at night, 70 during the day) that neither the heat or A/C run. I am starting to worry about mold throughout the house because I know it can grow at RH over 55%.

Fortunately I can somewhat control the output of the Vicks Vaporizer by adding less salt. It is a pain because I have to add a little bit of salt at a time or I end up with too much steam. I could potentially dump the reservoir and add very little salt for the late night fill up. I would then have to add more salt to the morning fill up and hope I got enough to steam properly without being home to monitor it.

By the time the plant starts flowering it should be hot enough where I live for the A/C to be running frequently which will lower the humidity. I also have a large dehumidifier if needed. Definitely don’t want to grow a healthy plant and then ruin everything with bud rot. What is your ideal RH for the flowering stage. I have been told 30 to 40%.

I agree. 16 day old plants will love the higher RH.

So do you think 77% RH is ok at night?


That young I wouldn’t sweat it for a minute.

Mine runs between 35 and 60 depending on how much AC or heat is going. I don’t pay that much attention to it except for:

When they are young I want RH >50%, and when in the latter half of flowering I want it <40%.

I do run a dehumidifier and run it down as low as I can get it the last 2 weeks in flowering to promote terps and to prevent WPM or any kind of mold on my buds. The only problem with running a dehumidifier constantly is that a dehumidifier will add quite a bit of heat to your tent as it does its thing. I have to crank up my air circulation when running a dehumidifier 24/7 to keep the temps down.


Exactly what I’m looking for.



Check this ok ?

Manicuring, Drying, And Curing [marijuana]

Right after all the plants have been harvested, it is time to manicure them. Manicuring is simply cutting off the leaves that were growing from the buds. Cut off all the leaves surrounding the bud, so that just the bud remains.

Work over a glass table or some kind of smooth flat surface. This will make it easy to collect all the material that has been cut away from the buds. It is lower in THC than the buds, but rather than throw it away, you can use it to make hash oil.

When manicuring the buds, use a pair of scissors with small blades (to reach hard to get leaves) that is comfortable on your hands. If you have a small crop, you can handle the plants with you bare hands. With a large crop, wear powder free latex gloves.

The latex gloves will collect trichome resin in a similar manner to the way live [marijuana] plants are rubbed to make hashish. The latex gloves have to be powder free or the powder will get mixed into the resin.

Do not touch anything other than the plants once you have put the gloves on. If you have to do something, remove the gloves you are wearing and put them in a plastic bag, prior to doing whatever it is that has to be done.

When finished, put on a pair of new gloves. Material on the first pair can be collected later. When you are finished manicuring all the plants, remove the gloves and place them in a plastic bag (to catch resin that drops off).

Put the plastic bag with the gloves in a freezer for 2-3 hours. The trichome resin can easily be peeled from the frozen latex gloves and consumed the same way you would use hashish.

If absolutely necessary, you can wait to manicure the buds. However, the job will take more time if you wait. Manicuring right after the plants are harvested will also speed the drying process.

Instead smoking [marijuana] directly after it is harvested and manicured, it is best to dry and cure it. Some new growers might be in such a rush to try the [marijuana] that they don’t want to dry the crop, or they might be tempted to put buds in a microwave oven to dry them out.

Drying [marijuana] After Harvest

You probably don’t want to smoke [marijuana] that is harsh and bad tasting. If you do not take time to dry the bud, you will not get the best possible smell and taste your crop is capable of producing.

Proper drying and curing will also ensure maximum potency of the [marijuana] you have grown. [marijuana] is not potent just after harvest. Some of the THC is in a non-psychoactive acidic form. Drying [marijuana] the right way will convert the non-psychoactive acidic compounds into psychoactive THC.

The area where the drying is done should be dark. Light and high temperatures (higher than about 80 degrees) will cause THC to break down into less desirable chemicals, this will lower the potency of the finished product.

A good way to dry the crop is to hang the buds upside-down by the stem, from some string or wire. The drying [marijuana] must have some circulation blowing over it at all times. A gentle breeze that circulates over all the plants is necessary.

A fan or two will circulate air within the drying room. Fans will aid in drying the plants evenly, and reducing the chances of mold.

If mold starts and is allowed to grow, it might ruin all of your crop. Mold looks like white fuzz and has an odor that is unpleasant.
You will have to keep the temperature and humidity within a certain range for optimal results.

Conditions should remain constantly somewhere within the following ranges, temperature should be between 65-75 degrees F, relative humidity should be between 45%-55%.

At temperatures lower than 65 degrees, drying time will be lengthened. At temperatures higher than 75 degrees, the heat will cause the outer portion of the bud to dry quicker than the inner part, and the taste will suffer.

At humidity levels lower than 45%, the [marijuana] will dry too fast and the taste will suffer. At humidity levels higher than 55%, the [marijuana] will take a long time to dry, and it will be prone to mold.

Keep a hygrometer and a thermometer in the drying area, close to the plants. A hygrometer will allow you to keep an eye on the relative humidity level in the room and a thermometer will display the temperature. Some hygrometers have built in thermometers so you can measure the temperature and humidity together.

Depending on the time of year and your location, a heater or an air conditioner may be necessary to adjust the temperature. To control humidity, a dehumidifier can lower humidity and a humidifier can be used to raise humidity. There are warm mist humidifiers and cool mist humidifiers.

A warm mist humidifier will raise the temperature while a cool mist humidifier will not affect the temperature. There are also humidifiers that allow you to switch between warm or cool mist. If you are going to purchase a humidifier for this purpose, take your climate into consideration and buy an appropriate humidifier.

Warm mist models will actually heat the water and release warm humidity. Cool mist water isn’t cooled, it just means that water is not heated. In most cases a cool mist will work best. To be safe you can get a humidifier that lets you switch between warm and cool mist.

Curing [marijuana]

It will take at least a week or two to dry the crop with temperatures between 65-75 degrees F and relative humidity between 45%-55%. You will know when the [marijuana]is dry if the stems snap or break (rather than fold) when they are bent.

Try smoking a small bud (1/2 gram or less) in a joint to be sure it is dry enough.

At this time, small buds will be dry enough to smoke. But larger buds should be cured (slow dried) to ensure that the [marijuana] is as potent and tasty as possible. If necessary, you can set aside buds that are less than 1/2 gram for smoking, while larger buds cure.

The cure normally lasts a week or two but some strains will do better if left longer. The aim of what you are doing is evenly finishing the slow dry process, so that mold will not grow when the buds are stored long term. Also, by the end of the cure, any remaining inactive THC will be converted to active THC (that increases potency).

To cure the crop, you will need one or more containers made out of glass or plastic. Some people say plastic can impart a taste to the [marijuana]. Some say plastic containers that some types of roll your own tobacco are sold in, have no negative effect on the taste. You decide.

Containers that have a rubber seal work best, but any type of container with a tight fitting lid will do. One quart canning jars do a very good job if you are curing a few pounds or less. They have a rubber seal and hold 2 or more ounces of [marijuana]
per one quart jar.

When curing quantities in excess of a few pounds, large (over 40 quarts) plastic storage boxes are recommended. They are not air tight, but will do the job when smaller air tight containers are not practical.

Gently place your [marijuana] in the containers (cut buds to size if the are too big to fit in the container) and put the top on.

Store the containers in a dark area where the temperature is between 50-65 degrees and the humidity is between 40%-60%.

You will have to open the containers for a few minutes to allow moisture to escape by fanning with your hand. If any moisture builds up on the inside of the cap on your container, wipe it off. Do this preferably 2-6 times daily, at regular 4-12 hour intervals.

You should also re-arrange the buds by giving them a quarter-turn once a day. This will ensure that different parts of the buds are exposed to the air in the container.

Keep up this routine for 7-10 days.

When properly dried, [marijuana] will burn evenly when smoked in a joint (if stems are removed). The taste will be as good as it can be, and the THC will have reached a point where it is ready to be ingested or stored.

You can keep any [marijuana] that will be consumed within a few months (1 year maximum) in the same containers used for curing, without having to keep opening them to release moisture.

If the [marijuana] is to be stored for more than a few months, you can use a vacuum sealer (designed for storing food) to seal the [marijuana] in an airtight environment. If stored in a dark area that is between 40-55 degrees F, the [marijuana]) in vacuum sealed plastic will remain potent for up to 5 years.

Dry [marijuana] can be stored in a frost-free freezer, but some of the THC on the outer part of the buds may be damaged when frozen.

A refrigerator is in the right temperature range but they tend to be humid (unless you can control the humidity).

If stored in an area of high humidity for months or years, even vacuum sealed [marijuana] can eventually become as humid as the surrounding air. This will necessitate drying it again before smoking. But, unless mold develops, humidity itself will not degrade the THC or make the [marijuana]) any less potent.

Light will degrade some of the THC, so dark containers can be used for storage. If you place the [marijuana] in a see through container, it will have to be located in a dark area that is not exposed to light or high temperatures.

Always make sure to properly dry your [marijuana]) prior to storage, if you grow your own or if the stuff you have is very moist. And remember that to preserve [marijuana]( potency at a maximum level, keep any exposure to air, heat, and light at a minimum.


This was a great read and very informative since I am a looking at this next process.
Thank you from a learning grower.


Great read , and knowledge gained