perlite turning rusty orange

my sprouts are about 4 days old and all the exposed perlite on top of all the pots is turning an orangy rust color. this happened with my last grow (which i had ph problems with but turned out ok) and on my last grow i used ff ocean forest. this stuff is some random off brand starter soil and the plants are doing ok but I was wondering if the perlite was trying to tell me something. its only the exposed parts. when i turn the peice of perlite over it is still white underneath. i found some ancient thread about it but the question never got answered and then the thread died. i'm using plain tap water and it out of faucet ph is always hovering at 7.0

I wouldnt worry about it lol. it probably soil sticking to the water when you water and sticking to the perlite.

Yea thats weird man! For real! That happened to me too but only on 1 of my plants pots..... And I was using the same perlite in the other pots and it didn't happen. All turned out fine tho, so I wouldn't worry much.

Your water supply may have a high iron content dissolved in it. That color could be iron oxide aka rust. Since perlite is white, I could see that possibility.

You should see the pre filter on my RO setup. That thing turns from pure white to nasty orange/brown from the crap that comes through the tap...And the town is rural and gets its water supply from a town well.

Dirty Harry said:

Your water supply may have a high iron content dissolved in it. That color could be iron oxide aka rust...

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bingo.... especially if your watering from a hose or sink that hasnt been used in awhile

IAm5toned said:

bingo.... especially if your watering from a hose or sink that hasnt been used in awhile

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that makes quite a bit of sense. i do run the water thru a brita filter after running the tap for a minute but i don't know how much of a difference that makes. is there a way I can test this inexpensively with some kind of kit? would this explain why when i turn the perlite over it's still white?

Total Head said:

that makes quite a bit of sense. i do run the water thru a brita filter after running the tap for a minute but i don't know how much of a difference that makes. is there a way I can test this inexpensively with some kind of kit? would this explain why when i turn the perlite over it's still white?

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dont worry about it. the same thing happens to my plants. For some reason its only on the surface and when you cultivate the soil on the top of the plant all the perlite below is still bleach white.

I would imagine it is just dirt particles and possibly metals that get trapped on the top when watering.

i find that cultivating the soil about a half inch down between waterings makes thing much more visually appealing.

I notice no ill effects from the brown on the perlite after 3 grows.

It's iron.

If it was iron it would be on both sides. It's most likely the start of a bacteria mold, or red algae. Shouldn't hurt anything.

But that is where the water is drenching it....from the top. Perlite is a craggy son of a gun and will pick up all kinds of particulates.

But you are right in that it shouldn't be a problem.

I got the same thing when using perlite. I assumed it was algae?

Orange algae? I don't know...it's possible. It does exist, but usually only underwater, as in aquariums.

I would think it would kill the weed (the water) to have the soil that saturated 24/7.

Maybe I'm wrong... (gasp). I have never encountered it myself. Just iron deposits, and sulphur.

I have the same rust appear on my perlite.
I simply rinse it off with the next watering and have seen no ill effects.
In fact, Cannabis is real tolerant of high Iron levels.
The only feasible downside is excessive iron can make it difficult for a plant to uptake Phosphorous.

Yes, that's true enough. You can get a brita and filter out the iron if you feel the plant is getting too much. Mine just get green as heck. I must have Goldilocks well water.

I have three wells to draw from, and I use the stinky water (sulphur) always. Not near the iron content (you can taste the difference).

I just let my water sit in 6 gallon containers for 24 hours to let the sulphur gas out. then it tastes as good as any store bought.

I know this thread is old, but thanks RIU for keep all this info on hand for Newbies!!!

EasyPound said:

I know this thread is old, but thanks RIU for keep all this info on hand for Newbies!!!

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Seriously, still being used to this day to answer my question! Thanks RIU community!

rusty old pipes for the water coming in your house?

Thank you guys !! Almost had a heart attack when I saw this on my pearlite . Crazy this forum is 10 years old lol

Rylew304 said:

Thank you guys !! Almost had a heart attack when I saw this on my pearlite . Crazy this forum is 10 years old lol

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Yeah lol this forum helped me get past my “WTF is wrong with the perlite?!?!” scare I had a few weeks ago

Same thing happened with some royal gold soil I used. Perlite turned orangey color. I don’t see the correlation with Iron since I’m using RO water at 7 ppm. So curious as to what might be causing it because i don’t think it’s iron.