06/08 - First day in week 5 in veg. I added some silica to the nutrient solution. Let's see how this work.
07/08 - Had some problems with the nutrient solution.
09/08 - Had to flush with plain water. The plant bounced back.
Only on one leaf of one plant. Is this some fungus or virus?
It looks a bit like coffee rust, but I couldn't find anything else like it.
How should I proceed?
Thanks in advance!
Pretty certain this is Leaf Spot Fungus otherwise known as Rust Fungus... and you'll need to jump on this quickly as it spreads fast... it spreads by spores that you can't even see so don't think you've got any time to waste here... I won't go into all the details of what you need to do as this article is very thorough.. Do give it a read and get going so you don't lose your entire grow...
https://www.urbanorganicyield.com/rust-spots-on-leaves-during-flowering/
Good luck!