Indoor Does increase in relative humidity decrease water uptake?

[lunarman]

Growing indoors in an arid climate and my tent would probably be under 20% RH if I did not have a humidifier. I know it was before I added a basic average sized humidifier that got me up to on average 35% RH. I bought a big console style evaporation humidifier and currently sitting at 50% RH. Plants are looking lusher with the increase in RH.

VPD, CO2, sealed tents, are too advanced for my current grower level. I'm just interested in the basics of RH and temp and basic air in and out. Just having a big ass humidifier that gets me up to 50% or higher is a big improvement I think.

But I'm curious if a higher RH will change how much my plants uptake water.

 

[lunarman]

Bump.

In the last day by big humidifier went thru its two tanks. 9 gallons of water in basically 24 hours. That seems like a lot for an 8x8 tent and a steady 50% RH. And I pay for RO water for it. It's not that expensive when you do refills but it's going to add up and be a lot of manual work to refill every day. I was hoping to go 2 days between refilling. So adjusted the fan speed from med to low to see if that slows down the water consumption but still result in 50% RH in the tent.

 

[lunarman]

also getting back to the op, I noted that my coco medium seems to be moister. Not sure if that's a placebo or not. But when do the finger knuckle check the top of the coco feels more spongy compared to when it was 30% RH. So do I wait for the top part of the coco to dry out before watering, but it will never really dry out because of the higher RH and then I'll end up under watering?

 

[Proph]

Sorry that this was missed! Yes, RH affects uptake of water. The technical term is transpiration. If RH is to low.. The plants roots have to work harder to transport water. If RH is to high, they dont work enough.. The sweet spot for RH is 40-50%.

In non ammended coco, you water every day with nutes.. Some people push it to every two days, depending on the size of the pot.. Coco is basically hydro.. Its almost impossible to over water, but easy to under water. I don't wait for it to dry out.

 

[Simplicio]

Staying in the green will maximize growth.
Pick your preferred grow temp, then use chart to see acceptable humidity values.

 

[lunarman]

Staying in the green will maximize growth.
Pick your preferred grow temp, then use chart to see acceptable humidity values.

Ever since I got the console humidifier and up to 50% I've been running outside the green zone. Heat was around 80F. I don't want to run higher humidity, so to get in to the green zone I have to reduce temp down to 70F. I dropped it down to 70F and I'll see how it goes. I can't imagine I'll see some amazing results in the plants in 24 hours. Might just have to trust the chart,.stay in the green zone and let the grow run out.

One plus for lower temps is less electricity required and less cost, at least in the winter.

 

[lunarman]

Staying in the green will maximize growth.
Pick your preferred grow temp, then use chart to see acceptable humidity values.

if you run a perpetual grow with seedlings, veg and bloom at the same time in a tent what temp and rh values would u select off that chart that is in the green zone? right now my rent is 50% and 70F so its in the green but not sure its ok for seedlings.

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[islandgrower]

if you run a perpetual grow with seedlings, veg and bloom at the same time in a tent what temp and rh values would u select off that chart that is in the green zone? right now my rent is 50% and 70F so its in the green but not sure its ok for seedlings.

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55% humidity based on the chart to get in the middle of the green zone. 1.13 is what I would aim for . If you have good air circulation . You do not want to go too high humidity to prevent mold on the flowering girls.


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[lunarman]

55% humidity based on the chart to get in the middle of the green zone. 1.13 is what I would aim for . If you have good air circulation . You do not want to go too high humidity to prevent mold on the flowering girls.


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i have active high cfm 4 inch inline fan for fresh in and 6 inch exhaust out. and a nice large oscillating fan and a big floor model for circulation so i think i should be ok for no mold.

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[islandgrower]

i have active high cfm 4 inch inline fan for fresh in and 6 inch exhaust out. and a nice large oscillating fan and a big floor model for circulation so i think i should be ok for no mold.

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Sweet . Seedling can handle lower humidity then is made to believe anything above 40% should be good. @912GreenSkell may be able to chime in on that

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