Start a new thread

101 to 116 of 116 replies

plant pauper

I love that you've made it your new hobby Patty.  Thanks for taking the trouble to update us on your latest "speriments".

Mine diminished a bit when I cut down the Roundup but I'm keeping a close eye for it's return. We've had less rain than normal this year so that has helped but I'm sure I haven't seen the end of this particular beastie!

Good bacteriocidal thinking with the Peroxide and the IPA. If you're ever looking for a job over here I'll give you an interview! 

We live in Kentucky and have a terrible problem with this green slime.

We bought 100 lbs of soda ash to dissolve in water and spray on our driveway.  My question should we apply when nostoc is active or inactive?  (Hope this works)

Also, what would you recommend to spray on the driveway in the future to prevent weeds and grass? I also used Round up in the past.

I am in Danville KY, it's just terrible need help desperately

Follow up:

We sprayed our driveway with soda ash.  We mixed up 25 pounds of soda ash with water to make a 25 gallon mix in our yard sprayer.  We had to do the mixes in small amounts to assure the ash was dissolved in hot water. Since our driveway is over 300 feet long we used  50 pounds.  After a week or so it rained.  We noticed it worked pretty good.  We repeated the process again with another 50 pounds, when we knew it was not going to rain for at least three days.  It rained again the day before yesturday.  We still have some slim left but I say we got rid of over 90% of it.

 This morning I went out and sprinkled about 30 lbs. of baking soda on the spots we had left . (I had tried the baking soda with a outdated box I had in my cabinet prior to the soda ash in a small area.  Put it on real heavy and it did work.  It has been several weeks and it still has not returned.)

Last note.  When you spray do it when the slim is active.

Thank you thank you Margaret Ibbs.  We drank a toast to you last night.  I used your suggested sodium carbonate solution last Friday on the horrendous nostoc commune growing on my gravel drive, and today, Monday, it looks totally dead.  I shall re-treat in a fortnight as you suggest, and hope to see the last of it for ever.  (Downside - no more glyphosate on the drive weeds, since several posts suggest this could be causing the problem.  However hand-weeding will be a small price to pay to be rid of this monster.)


I have joined this debate because I have NOSTOC too. It is growing within the clumps of alpine plants which prefer a well-drained soil (so perhaps I haven't got that right!), - I am in one of the drier parts of Wales. This means that drastic treatments (fire, for instance) are ruled out. If I 'caught' the nostoc, it may have arrived in a bought plant or two.

The recurrence of 'after Round-up' in your comments hints that perhaps there is a link. I wonder if Round-up kills something which otherwise would live off, or combat, the Nostoc? I mention this as while a link with Round-up may be proven (eventually) it does not mean that Round-up is the cause. Neither does it prove it isn't.

Next I will try Washing Soda (= sodium carbonate). This is a close chemical relative of baking soda, but cheaper. It does not have the formula quoted earlier (NaCa3) as I think this is a mis-keying. If you heat baking soda (sodium bicarbonate) it gives off carbon dioxide and turns into sodium carbonate. Leave this around and it will absorb some carbon dioxide from the air and turn into baking soda. Not completely, but this is to show how closely the two are linked as chemicals. And if the weather has done with being dry for this year, the glass sheet is going over the raised beds next weekend, until the daffodils are out again.

Keep in touch, I am interested in your soda results.

plant pauper

I rushed out after reading that  post and sprayed mine. I'm due to do a second dose next Monday so I'll report back when I have some results, +ve or -ve. 


You're right bobweight - some time ago I did mis-key the formula of sodium carbonate. Wikipedia confirms the formula as Na2CO3.

Wikipedia also describes sodium carbonate as the water-soluble sodium salt of carbonic acid. I wonder whether its application to the Nostoc in some way re-creates or releases the carbonic acid constituent which in turn destroys the dreaded stuff. (Fortunately) my gravel does not have the problem so (unfortunately) I can't put this to the test myself.


London Kentucky here...we have this crud EVERYWHERE & have had it for years!  This is the first time I've tried to research what it was since none of my family, who live within a rock's-throw of us have it.  

Its in the gravel & yard but never had it on our sidewalks or patio, thank God!  We will try some of this stuff to get rid of it.  But is there a consensus on what it is?? Fungus, mold, alien poop???  Argh!! 

Appreciate all the info!!

I have battled this for years. However, This year I tried Pool Algae Cleaner. You can buy by the Gallon at Walmart ,etc  It is only about $7-8 a gallon. I waited for a rain and then as it started to dry out but still damp (12-24 hrs later ) I sprayed on through a garden sprayer. It turns a slight brown almost immeadiately and Within a few days you can really notice it dying out. You may need to treat a few times but at the low cost of treatment  it was well worth it. Good Luck!


I said I would reply when the rain showed me which of my treatments has killed the Nostoc (the green globby algae-like stuff that appears in gravel driveways after application of glyphosate to kill weeds). I could not use everything that might have worked because I had to find something not toxic over time to pets if they got it on their feet.

Only THREE treatments have worked, so I'm going to ignore the accounts of everything else I have tried. The three treatments are:

Fire, using a propane torch to burn the Nostoc when it is crispy and black and dried a few days after a rain. This gets rid of it right away.

Washing soda (sodium carbonate, obtainable in the laundry section of a grocery store)

Slightly diluted concentrated bleach (sodium hypochlorite, also obtainable in the laundry section)

When applying either of these chemical substances, wear pants and wear shirts with sleeves and wear socks, shoes, and gloves. Also wear a mask so as not to breathe any fumes or get chemical splashed on your face. Wear goggles so as not to get it in your eyes. Keep the treatment as far away from your face as possible. 

At first I did not think the sodium carbonate had worked. I applied it as powder and as a solution (1.5 cups of powder dissolved in 1 gallon of water and applied with a sprayer like one would use for weed killer). I did not think it had worked because even though it killed any accompanying moss and turned the Nostoc (the green globby stuff) a sickly yellow, it appeared to return after the next rain. But after the third rain, the areas treated with sodium carbonate were finally clear.

I got the concentrated bleach (it has the word "concentrated" on the jug) and mixed it 3 parts of the concentrated bleach to 1 part tap water. I also used a sprayer similar to a pump weed sprayer. It turned the Nostoc a sickly yellow. The globby masses were gone by the next rain. 

Each solution worked best when applied to freshly swollen Nostoc just after a rain. Also, picking up as much dried, crispy Nostoc as you can before a rain really helps the treatments to work. DO NOT rake it as this crumbles it and acts like spreading seeds. 

Last edited: 06 September 2017 00:45:04

plant pauper

I applied my washing soda and that seemed to knock it back a bit but I haven't had a long enough dry spell to re-apply to the stubborn parts and the parts that I may have missed. 

It's top of my list of jobs-to-do as soon as there's a dry day.

Congratulations on your success Patty  and do let us know if it continues. 

Hi all,

I have been following this thread for a few months and I have finally got round to trying out Margaret Ibbs washing soda solution. It has been very wet here the last few weeks so this Nostoc Commune has taken over the gravel driveway, especially bad along edges and certain spots where I know I used round up/ weed killer in the Spring. 

So I checked the weather today, dry all day for once. The Nostac Commune is still damp and active so thought it was a good time to blitz this thing. I used pretty much the same solution as Margaret Ibbs (if not a bit extra washing soda... for luck!) And sprayed the driveway with a fine sprayer (same one I would normally use for killing weeds). All I can do now is wait it out and repeat the process in two weeks time. I will update you soon. 

Also, can anyone recommend what can be used to kill weeds now that we are fairly sure that round up/ glyphosphate is causing this stuff to appear. Hand picking weeds in theory is the best option I know but it would be near to impossible to do this, there are weeds everywhere!!! Would this washing soda solution kill weeds too?

Wow...thank you so much to those who have put time and effort into this post.

For the 1st time EVER I have seen growth of this alien type gue on my hardcore near my shed. 

I can confirm I purchased "Roundup" spray ready made and sprayed weeds near my shed about 3 weeks ago (never used roundup before). I'd be confident in saying that this is the route cause.

I will be burning the area today and will treat using methods in this post. Will keep you updated on progress.


This awful slimy,slippery  stuff has appeared on the sloping gravel path  which leads to my front door.I think it has been there about 4 weeks and and I am concerned about people,including me,slipping on it.I don't want to use anything toxic,as I garden organically,and also because my cat sits on the path.I would be really grateful for any ideas of how best to eradicate it!..Thank you.


Sign up or log in to post a reply