Perlite is turning green on the surface


Some of my perlite in my 70/30 coco perlite mix is turning green, is this algae something to worry about?
I water when the top starts to dry a little.
60-65% humidity
Plants are 4weeks from seed and growing very good.
I do have some path off I was thinking about adding a little to my next water to see if it clears it up.
Any recommendations?


Does your water sits prior to use? The green is algae. If algae is present other nasties could also be breeding. Drooping would be the symptom you are on the lookout for. Adding a microbial innoculant that contains trichoderma or Bacillus Amyloliquefaciens may help, but if you keep your water clean and use fresh well oxygenated water, you shouldn’t need, although good microbes can also help with nutrition of the plant.

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It happens to my perlite also. I use a 50/50 coco perlite mix and the top layer of perlite is always greenish. Never has caused me any issues. Just make sure you allow adequate dry time between waterings and you should be fine.


It’s over watering u need to make sure ur pots dry out in between cycles.


I was going to say it’s from over watering as well


Also great for root development(makes them search for water. @Countryboyjvd1971 Just had to beat u to the punch lol.


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I use tank water that comes in at 5.5ph and 6ppm, I did think i may have over watered them the other week because my run off ppm was a bit high so I gave them a flush to bring it back down.
I’m now letting the top completely dry out and the pot get really light before watering.
Does it sound right to last around 3-4 days from a watering?

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@Uncle-edd that’s sounds about right
You say tank water ? You talking fish tank if so it may be from any organic material in the water from the. Fish


I’m confused. I thought if you were growing in coco you watered every 1-2 days. If that’s the case aren’t you pretty much always keeping the coco wet? Especially if this is the guidance:

1.) Aim to give water every 1-2 days

Cannabis plants grown in coco tend to do well when they’re getting water every 1-2 days.

2.) Give enough water to always get at least 10-20% runoff water out the bottom


the green is definitely algea. You said ppm is high. What is it? I would re-pot with clean soil.


@Countryboyjvd1971 sorry I ment rain water, and ok thanks for your help! First time using coco and perlite.
Well my ppm broke so while I was eating on my new one I mixed a batch of Dutch fest a&b plus seasole (sea weed) I mixed half the reccomend amount and the run off was just over 500ppm so I flushed it then and a couple days later got the ppm down to 250 ish and the green came a couple days later.

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Damn auto correct, I was waiting for my new ppm meter to arrive

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Stop eating your meters you savage, lol


There’s your over watering situation :+1:
You’ll be fine my friend