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Humidity And Marijuana Plants

Humidity And Marijuana Plants

We are going to take some time to delve into some much-needed information to further you understanding of the importance of humidity levels when growing marijuana plants.

 

 

 

 

 

 

 

What is humidity

what is humidity marijuana

Humidity is expressed as the quantity of water vapor in the air. Humidity plays a necessary role in influencing how much evaporation occurs in cannabis plants. Your plant will take in more nutrition and water when the humidity is low. If for any reason the evaporation strain get to be too much, marijuana plants will guard itself against scarcity by closing its stomata. So naturally this will stunt the growth of your plant due to the lack of water absorption.

This is why you must have the proper humidity levels in your marijuana factory. When the plant is in the growth stage, it will need high humidity, unlike the blooming phase. This is mainly because the roots of baby plants are much smaller. Measure the humidity using a hygrometer. In the first stages of growing your plant, the humidity can be about 70%, and you can reduce it by 5 every week until it gets to 40%. Included in this article is a helpful schedule to assist you with the right information on humidity levels for both indoor and outdoor growing.

Read the article Structure and function of stomata for more information about evaporation

Relation to temperature

humidity and temperature in your marijuana grow roomBefore we go any further, we have to discuss the connection between temperature and humidity. First you must understand that the percentage of absorbable water is determined by the temperature. At the temperature of 68 degrees Fahrenheit, air can take in up to 7.2 ml of water. In this case, air has a corresponding humidity of 100%. With temperatures and humidity such as that you are guaranteed to see absolutely nothing because the water vapor is very high. At 32 degrees Fahrenheit, the air will take in around 5 ml of water. For this reason, air is much drier during the winter time than the summer months.

Download my free marijuana grow guide at this link for more growing tips

Since you will be airing out your grow room quite frequently, you will end up releasing the humidity as well. So you have to be sure that your marijuana factory is always moist so the humidity level goes up. Later in the article you will be informed of options for adjusting the humidity levels.

Clones

Humidity and cannabis clones

At first your marijuana cuttings will have very small roots so they are not able to take in much water yet. At this stage, you want them to evaporate a very small amount of water. Cutting will only evaporate a small amount of water when the humidity is high, and require fewer roots. Another way to reduce the amount of evaporation is chopping the bigger leaves halfway from the cutting. A humidity of 70% is exactly what you want when putting the cuttings in your marijuana factory.

Your cuttings will begin growing roots in a clone box when the temperature is around 71.5 degrees Fahrenheit in a very humid environment and fluorescent lighting. I suggest the cuttings go beneath a 600-watt HPS lamp in an environment with 30% humidity for good results. For as long as the 2nd or 3rd week of blooming the roots are going to grow the size of the actual plant. The roots must be durable for proper water and nutrient absorption.

Read the article How to make marijuana clones for more information

Seedlings

Humidity and cannabis seedlings

Seedlings require a separate set of rules since they have a taproot at germination that takes in moisture and grows fairly quickly. Never clip the leaves of a seedling. The leaves are necessary for absorbing light and evaporating water. To help the seedlings take in water and nutrition through its leaves, have the humidity at high levels. Begin at 60% and slowly work your way down to 40%. Click this link to buy marijuana seeds

Flowering stage

Humidity in the cannabis flowering stage

As your plant start flowering, you can gradually decrease the humidity level. At this stage the roots are very mature, so the plant is able to take in the most nutrients and water. You will want to reduce the humidity level in the flowering stage since mold has a tendency to flourish in high humidity environments. With age, there is a higher chance of your marijuana plant getting mold. As a result of the high humidity, water gathers around the tops and that when mold has the opportunity to develop. Bud rot is the most frequent type of mold.

Read the article Flowering stage for marijuana plants for more info

Schedule and levels

Follow this schedule to ensure you give your plants the right amount of humidity for optimum growth. Notice there is a difference in clones and seedlings.

Clones humidity level
Growth Week 1: 70%
Growth Week 2: 70%
Flowering Week 1:  65%
Flowering Week 2:  60%
Flowering Week 3:  55%
Flowering Week 4:  50%
Flowering Week 5:  50%
Flowering Week 6: 45%
Flowering Week 7: 45%
Flowering Week 8: 40%
Flowering Week 9: 40%

Check this complete Marijuana Grow Schedule with temperatures, humidity, watering and nutrients tips

Seedlings humidity level
Growth Week 1: 60%
Growth Week 2: 60%
Flowering Week 1: 55%
Flowering Week 2: 50%
Flowering Week 3: 50%
Flowering Week 4: 50%
Flowering Week 5: 50%
Flowering Week 6: 45%
Flowering Week 7: 45%
Flowering Week 8: 40%
Flowering Week 9: 40%

How to raise

Raise cannabis humidity

So, you have a few options for raising the humidity in your grow room. For starters, you can try spraying water on the walls and flower. Also, try putting the lights further up so the temperature will go down a little near the plants. This way you won’t have to turn on the extractor fan as often. If you put bottles or buckets of water around the grow room, or even wet towels, this will raise the humidity level.

Now, the best way to accomplish your goal is using a humidifier. Humidifiers transform water into water vapor and shoots a constant mist consisting of high humidity into your room. Depending on which one you buy it may come with a humidistat (wiki) to monitor the humidity level and will even turn on if it goes beneath the value you set it to. Buy a humidifier at this link

How to decrease

Decreasing humidity in marijuana grow room

Once your marijuana plant starts flowering the humidity will need to be decreased, so it is necessary to dehumidify. Try using the extractor fan on a higher setting than usual or even you can even shoot cold air into the room. Dehumidifiers are most certainly your best option. It has the capability of taking moisture from the air and draining it or holding it in a reservoir. Make sure to get a larger humidifier because the smaller ones fill up quickly.

Download my free marijuana grow guide at this link for more growing tips

Keep in mind that the humidity outside may influence the humidity in your marijuana factory. For instance, if on a rainy day the humidity increases quickly, you can shut off the extractor fan or turn it to a much lower setting. Make sure the temperature doesn’t rise too quickly, because you’re getting less cold air from outside.

How to measure 

How to measure the humidity

Hygrometers are used to measure humidity levels (wiki on hygrometer at this link). All you have to do is put it over the plants, so long as it is in an area that easily aired out. The analog hygrometers cost $5 and you can buy a digital one for $10. The higher priced hygrometers are usually of better quality. For ease of use, get the one that has a wire attached to it. This makes it easier to see the humidity without having to turn the lights on in the room. These devices have a built-in storage bank that tracks the highest and lowest values, to help you determine how well you stayed within the preferred range. Buy the best hygrometers at this link.

Water

Watering cannabis and humidity

Watering your plants causes the humidity to go up quite a bit, which is fine when in the growth stage because you just spray the floor and walls to raise the humidity. During the flowering stage, humidity levels often go up way too much after you water your plants. Once the lights are no longer on in the grow room, the temperature decreases and extracting a lot of hot air is unnecessary, which usually is the cause of humidity increases.

Nourish your plant with water once the lights are on, that way they will evaporate most of the water throughout the day. Understand that spraying water on top of the buds is pointless because you will raise the possibilities of the humidity rising and leading to mold.

Outdoor plants

outdoor humidity cannabis

Humidity is much less of an issue when growing your cannabis plants outdoors. The springtime and the start of summer offer higher humidity which works just fine since there are no buds present on the plant for moisture to gather. Any moisture on the plant from morning dew will easily evaporate throughout the day.

Once Summertime ends, the flowering stage starts and there is a shift in the climate, resulting in cooler days and more rainfall. This usually makes the humidity higher. In the cooler months, the morning dew could be an issue since the sun is not guaranteed to come out and the temperatures are sometimes too low to evaporate it.

Luckily a tad bit of rain will not cause the buds to rot, but just in case you may want to be on the lookout for this. In the last of the blooming stage, it might be a good idea to brush the dew off your marijuana plants in the mornings. If you notice that rain in expected, go ahead on move your plants to a location where they will be kept dry, away from the rain. It is always best to take the necessary precautions.

Thanks for reading. Please leave comments or questions below.

Robert Bergman

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Comment Section

20 thoughts on “Humidity And Marijuana Plants


By Stu on 13 August 2014

Thank you! Perfect info at the perfect time 🙂


By Mick Malkemus on 14 August 2014

Robert, are you certain the growth aspect is only two weeks? My plants take at least 4-6 weeks of growth.


By darcman on 14 August 2014

thanks robert was wondering why my plants seemed to stop growing. I have amnesia haze in 7th week of flower and it looks like they just stopped growing. I am going to alter the humidity like you said and see what happens. I will let you know how it works out . Thanks from a newbie keep it green !!:]


By Mark Kubin on 12 December 2014

me learned alot


By Lori Pacheco on 17 June 2015

I have a plant that is buding n has been for 12 weeks. Mostly orangey brown but I don't know when it's read? I need ur help..MAJORLY..


By John Henry on 17 June 2015

Thanks. I just moved to Arizona and there is no humidity here.


By CarolJune Quandt on 18 June 2015

You rock!!! I'm sharing you with my friends & my children.


By Mike on 18 June 2015

I am starting my seedlings with 19 hrs. Of light 8-9 hrs outside the plants seem to love it but it's 90-98 degrees everyday. I use fluorescent the rest of the time. Isn't the high temps bad for them even though the sun is Nat.


By latewood on 18 June 2015

Lori. I suggest you join our support forum, and post us a picture in order for us to see what your issue is. I am sorry, but I did not really understand what you are asking. 🙂

Mike. I suggest you invest in a shade cloth. 50% should do.


By Attic Flowers on 23 June 2015

Great info really helped me alot, now i can have a strong finish.


By Foirx on 27 August 2015

I have been exploring for a bit for any high-quality ateiclrs or weblog posts in this kind of space . Exploring in Yahoo I eventually stumbled upon this site. Reading this information So i'm happy to convey that I have a very good uncanny feeling I found out just what I needed. I so much indisputably will make certain to don?t forget this website and give it a look on a constant basis.


By k capoferri on 1 September 2015

hi, so far this is the simplest to understand info on raising and lowering the humidity in my grow box. thanks.


By Mark on 11 March 2016

Bob,

FYI... When viewing your site with a Mobil device, plastered across the top of the web page is a large view of your logo. Not a big deal unless one is attempting to read your comprehensive compilation of info. in public places I.e on a 2 hour flight, ect. ..
Thank you,
Mark

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