Curious about humidity

Anyone ever have any big issues with humidity being too low? if so what effects were there?

With very low humidity, the plant is drawing water from the soil at a very high rate , and if the humidity is too low, the plant is unable to draw water at a rate equal to loss through the stomatal openings.

One of the reasons I mist my plants…


Thanks for the reply! Very interesting… I wonder coulld a humidity of 40% in a dwc grow cause a retardation of growth and even leaf death?

You might consider getting a humidifier. You might need both if your humidity climbs at lights out.

See how much you need to raise humidity— Plug your numbers into this: VPD Chart

One symptom of low humidity is stunted growth and under severely low humidity, the plant will wilt and die because even its protective mechanisms cannot offset the water stress imposed by the lack of atmospheric water. …but 40% isn’t all that bad is it?

1.7kPa very interesting stuff. Thanks gents

I’ve found I can bump the humidity up if I stuff the plants inside the closet and shut the doors… may play with a schedule of keeping them open and closed for different amounts of time etc.

I often run in low humidity… 35-40. With zero adverse effects. Soil and coco.


I wonder if it matters what modality you’re using to grow… hydro vs soil coco etc.

The only reason I’m wondering is because my plants went through something this grow that I still can’t really nail down but it was def my fault. As I changed multiple growing parameters at 1 time. Nute over load, burn, deficiency, plants got knocked over, changed my light to much higher power… plants turned crispy and never really recovered. I thought I was frying them with the new light buts it’s not even warm at the leaves. So it got me wondering about humidity…

Anyway thanks for the insight all.

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You can add a pan with water to raise humidity and/or mist your plants. Low humidity for me is below 33%. It may have been a Combination of errors.

Think you’re def correct a combination of errors!

Thanks again to all for sharing your knowledge .

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