The most effective solution, discovered by Margaret Ibbs on p.4 of this thread, was to dissolve 1kg of washing soda in boiling water in a 10 litre watering can, top it up with cold and water it on to "expanded" nostoc, on a dry day, through a fine rose. She used 3 cans on her 20' x 12' gravel, repeated once I think, and had no recurrence of the problem.
Since 2019 I've lived in east Clare, in the west of Ireland.
There's clearly a connection between the appearance of nostoc and the use of glyphosate. It seems to thrive in poorly drained, alkaline conditions.
It's on the council footpath (broken tarmac) between my house and the town - presumably the council sprayed the weeds... hope I don't spread it onto our gravel drive...
I'm with you, @Hazel-1 - congratulations to Margaret Ibbs! We should have a Forum Award for the most useful idea on any thread.
Since 2019 I've lived in east Clare, in the west of Ireland.
Have exactly the same problem here in west Co Clare. I have a very large back stoned area - approx. half an acre - and it's covered in this "algae" whenever it rains. Going to try the washing soda I think.
Without ploughing through all the previous pages, I can confirm the correlation between the use of glyphosate and this 'seaweed' slime. I saw on a different chat thread that using soda seems to be the best cure although I haven't tried it yet!
After reading ideas here, I used 1 lb. of washing soda to 2 gallons of water and sprayed the Nostoc when it was active (jelled). I made a second application 14 days later. The Nostoc has dried up, and even through heavy rain, has not revived! I am quite happy with the results and I will use it again on any Nostoc that springs up!
We get nostoc on the driveway here when there is heavy rain for a while and when the weather becomes drier it shrivels up and disappears. I couldn't read through all the different pages of how to poison your garden but am much happier to see a bit of nostoc every now and then than to consider so many toxic chemicals being applied to what I like to keep as natural an environment as possible. It fixes nitrogen from the air so is likely to be providing some free fertiliser when it breaks down and I read it can be eaten as well but wont be trying that. I could understand if it was creating a slip hazard where it is growing but moss, lichens and algae are very important to supporting life in the garden so I'm surprised to see so many people so eager to poison it.
I have been researching this problem with the Nostoc since it has become very bad here. I found Margaret Ibbs information to be most useful and I plan to follow her formula soon. I will report my findings after a few weeks. Yes, I have read every one of the comments and thought a great deal about how to handle the situation here. Thanks to everyone who voiced their results!
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There's clearly a connection between the appearance of nostoc and the use of glyphosate. It seems to thrive in poorly drained, alkaline conditions.
It's on the council footpath (broken tarmac) between my house and the town - presumably the council sprayed the weeds... hope I don't spread it onto our gravel drive...
I'm with you, @Hazel-1 - congratulations to Margaret Ibbs! We should have a Forum Award for the most useful idea on any thread.
Someone was asking about it this morning.
https://forum.gardenersworld.com/discussion/1047016/what-is-this-strange-slime-in-my-garden#latest
I live in west central Scotland - not where that photo is...
I live in west central Scotland - not where that photo is...