Is the high humidity of seedling phase bad for the carbon filter and/or LED lights?

Hello my friends. So I’ve gotten my first grow kicked off and my seedlings have emerged! Yay! I read somewhere (maybe this forum, maybe reddit) that the high humidity of the seedling phase can have a negative effect on your carbon filter and possibly your LED lights as well.

I got worried about it and turned my fan off. The problem is now my humidity is stuck in the mid-high 80s. Before that I had my environment dialed in, which took some time and I was pretty impressed by, considering I’m using a cheapy humidifier (it does have a humidistat) and a tiny non-digital space heater.

Can anybody give input on this?

Too small for an exhaust fan anyways. Just turn it off, and let the humidity rise. 80% or higher is good for seedlings.


Led = fine
Carbon filter = No Bueno


High humidity not good for carbon filter but don’t need to be using it at this stage, save it for flowering.


Maybe I’m wrong here but I use the dome technique which I believe keeps the humidity within the dome and doesn’t effect the tent RH in general. Also think its easier to control dome RH than entire tent. My 2 cents.


I’m listening… Can you tell me if you are using a regular seedling dome, like I’d use for any plant? Is this a DIY thing…?

I just cut the rim off a clear solo cup, invert it on top of the base solo cup.

I use the plastic cup from a DQ sundae. take cares of my love for ice cream and growing LOL


I specifically use hose clamps with big convenient wing nuts on my exhaust line to my filters because I keep them disconnected until my plants are far enough along to start smelling. Good quality filters are expensive, there’s no point in wasting their life expectancy on seedlings. Just run your fan without the filter, and then simply connect the duct to it when the plants start smelling.


Ooo I like this solution :smiley:

This isn’t too humid?

I probably just spritz the cup before photo. This is her now

I like the DQ cup idea! I cut the bottoms out of these deli containers and they work great as well.