Having trouble raising RH: help please

[jimgriggs]

My tent does an passive negative pressure intake. The tent is inside a shop and the RH in the shop is at 70 ish. I have a Cool Mist humidifier. I run it and it barely touches the RH. I’d like to be at 55 but im at 42 and sometimes lower. Temp 78.

Yes, I know I’m in the range for flower. And yes I’m splitting hairs here. But my mission was this grow to get temp and RH dialed in.

Info below…All help and criticisms welcome.

Blue Cheese
4 plants
Day 18 F
4x4 tent
Happy Frog Soil 5 gal buckets
1000 w HPS
78 F
42 RH
Watering every 4 to 5 days

 

[KingJohnC]

How are you measuring the relative humidity in the shop area and inside the tent? Can you provide some photographs of the tent and area the tent is in so the equipment setup in use may be considered?

 

[jimgriggs]

I’ll have to wait to get the pictures when I get home. I’m measuring the temp and humidity with a Govee and my humidistat gives a second reading.

 

[KingJohnC]

Do you have another thermometer and hygrometer you can verify the accuracy of the govee units information with? I am attempting to first verify the accuracy of the measuring tools and with photographs may be capable of giving an opinion on the equipment location of selection alteration on either system setup or location placement to improve the use of the current equipment's ability.

 

[marcus611a]

My tent does an passive negative pressure intake. The tent is inside a shop and the RH in the shop is at 70 ish. I have a Cool Mist humidifier. I run it and it barely touches the RH. I’d like to be at 55 but im at 42 and sometimes lower. Temp 78.

Yes, I know I’m in the range for flower. And yes I’m splitting hairs here. But my mission was this grow to get temp and RH dialed in.

Info below…All help and criticisms welcome.

Blue Cheese
4 plants
Day 18 F
4x4 tent
Happy Frog Soil 5 gal buckets
1000 w HPS
78 F
42 RH
Watering every 4 to 5 days

If you say you're at day 18 a flower your humidity is fine

 

[marcus611a]

Honestly depending on where you're at and flower it's good to let humidity drop the 30% to increase trichome production. Lower humidity in flower has always worked for me

 

[jimgriggs]

Do you have another thermometer and hygrometer you can verify the accuracy of the govee units information with? I am attempting to first verify the accuracy of the measuring tools and with photographs may be capable of giving an opinion on the equipment location of selection alteration on either system setup or location placement to improve the use of the current equipment's ability.

I too questioned the Govee’s accuracy. I’m tested it against a few other Govees and the humidity read out in my house. It is within 1%. I will get some pictures to you guys after work on my set up. I appreciate all the help!

 

[KingJohnC]

You are welcome!

 

[732002]

Slow the exhaust fan down a bit, better RH is too low than high.

 

[jimgriggs]

Honestly depending on where you're at and flower it's good to let humidity drop the 30% to increase trichome production. Lower humidity in flower has always worked for m

Slow the exhaust fan down a bit, better RH is too low than high.

Agreed on that point. I have it dialed all the way down. I’ll try to post some pics of how I have equipment arranged when the lights come on.

 

[KingJohnC]

There is a better understanding on the effects of humidity and growing cannabis plants Vapor Pressure Deficit

The Downlow On Vapor Pressure Density - How Does VPD Affect Cannabis Plants?

 

[jimgriggs]

Do you have another thermometer and hygrometer you can verify the accuracy of the govee units information with? I am attempting to first verify the accuracy of the measuring tools and with photographs may be capable of giving an opinion on the equipment location of selection alteration on either system setup or location placement to improve the use of the current equipment's ability.

Here are some pics. Showing the set up. In-line draws air across the hood, cooling the light. I use negative pressure to draw the air from a bottom duct. I have a humidifier down low, and a small 4 inch fan blowing that around right next to it. A larger 12 inch hurricane is above the canopy.

 

[CultivationArt]

Use the online vpd chart. It was a serious game changer for me for my veg tent. Keep your plants in that sweet spot and they grow as fast as they would outdoors. I hope that helps at all. But def don’t be scared of humidity. Cannabis plants love high humidity in veg but as long as you have your balance dialed in correctly to chart between temperature humidity and surface temps.

 

[KingJohnC]

There are safety rules when using electricity and water in the same enclosed space. Electricity mounted only above the waist, water only bellow the waist. Any other arrangement long term proves hazardous or fatal.

Please make certain all electrical cords are a rated 12/3 Contractor Grade Extension Cord and properly secured.

Please secure the electrical extension cord to a tent pole support with either rubber lined cable clamps or zip ties. The electrical extension cord is a electrocution hazard when in any area or environment the eventual spillage of liquid will present great danger.

Your equipment is quite well managed. I like that you have included wooden trays for solidly mounting plant supports.

Below 16 Celsius or 62 Fahrenheit many plants metabolisms are not able to sufficiently assimilate nutrients for growth. Allow the plant to remain above 19 Celsius or 65 Fahrenheit. 23 - 27 Celsius or 73 - 80 Fahrenheit and 55% - 65% humidity is ideal for vegetative growth and 30% - 50% humidity in flower.

Please cover the light on the front of the fan as the red light affects cannabis plants. Is this the space heater located inside the tent? If this is also the space heater you refer to and it gives off visible light it will cause problems with light stress.

When using rope ratchets if you place a double knot secured with a trimmed zip tie at the highest travel point and lowest travel point you can easily change the height of the equipment without damage if the rope ratchet fails to lock into position.

A larger 12 inch hurricane is above the canopy.

Does the large fan oscillate and move the plants? You want alternating movement to stimulate the cannabis plants to create strong stem and branches for flowering.

I believe that the humidifier is undersized for the area, a larger output unit may be more suitable for the cubic feet of the areas to effectively raise the relative humidity level.

 

[jimgriggs]

Use the online vpd chart. It was a serious game changer for me for my veg tent. Keep your plants in that sweet spot and they grow as fast as they would outdoors. I hope that helps at all. But def don’t be scared of humidity. Cannabis plants love high humidity in veg but as long as you have your balance dialed in correctly to chart between temperature humidity and surface temps.

Yes, the VPD chart is what inspired me to be a stickler about humidity. My problem is about getting the humidity UP. I have no problems with being dry. Do you have a favorite infrared for leaf temps?

 

[KingJohnC]

Infrared will negatively affect cannabis plants growth and cause light stress.

 

[jimgriggs]

Infrared will negatively affect cannabis plants growth and cause light stress.

Thank you. That was an older pic, and another member pointed out the same. I wouldn’t have caught it without you guys and I’d be herming in a few weeks!

 

[CultivationArt]

Yes, the VPD chart is what inspired me to be a stickler about humidity. My problem is about getting the humidity UP. I have no problems with being dry. Do you have a favorite infrared for leaf temps?

I bought the 30 dollar one on Amazon.
benetech is the brand. It works very well from soil temps outside to how cool my drivers are running. Dab rigs. Not quartz unless seasoned/fogged. And even deep frying too. I can send you a link.

And I’m sorry For the wrong answer.

I just use a decent size cool mist humidifier for raising my rh.