Moss Killer

[Dave Liquorice]

Nice house wall painting weather, patching up the few places the paint has failed. One patch I *know* I wire brushed and repainted last year. It's failed again, because there must be moss embeded into the stone/old lime mortar.

So how to kill the blasted stuff, preferably in one hit and permenantly. Will Roundup do it? The weather looks set fair for a day or two so I could squirt it tomorrow and leave it for a couple of days to get down into the roots before removing the top growth and repainting.

[David Hill]

Not a hope in hell, You will need something like Formaldehyde, foul stuff to use and will want a couple of weeks to kill it properly

[Janet]

No you need a specific moss killer. Shed sells something for treating mossy roofs or you could use ferrous oxide in water, the active ingredient in lawn moss treatments. When it's dead brush it out of the crevices with a wire brush.

Talking of moss killer I posted a query a few weeks ago asking advice on about dethatching the "lawn" which had become so mossy it was sodden and unusable, grass rapidly retreating.

I borrowed an electric lawn scarifier to try, which was so effective I went out and bought the same model (£60 in Dobbies GC, same in B and Q). It raked out enough moss to fill 16 cubic-metre builders bags. Then I treated the lawn with a moss, weed and feed gritty stuff. Huge black patches where it had been pure moss.

However, weeks later the moss is all gone, the ground is not nearly as wet and spongy and and the grass is rapidly growing back into the gaps and looking good. Lots of work but worth it.

Janet

[Tim Lamb]

In message , Janet writes

Might be a good idea to *spike* the mossy bits with a garden fork to try and improve the drainage otherwise it'll be back:-)

[harryagain]

You can buy algecide at your builders merchant. Give it a few doses. Roundup doesn't kill moss.

[polygonum]

Sounds like Biggles and Co. should be very wary of that. :-)

[Chris Hogg]

Along with what the others have said, Jeyes Fluid will kill moss, but the smell lingers for a week or two and I doubt if it's permanent. Creosote may also work but I have no experience. As Janet was thinking, ferrous sulphate is traditionally used to treat moss in lawns, but this will slowly oxidise, will probably give you a brown stain, and having oxidised may lose its effectiveness, but I don't know about that last bit.

Another thought, and I don't know how well it would work, comes from the idea that if you run a strip or wire of bare copper along the ridge of your roof, the very slow bleed of copper as it corrodes prevents moss from growing on the roof. Perhaps you could try painting the patch on your wall with a dilute copper sulphate solution, or a copper-based fungicide such as Bordeaux Mixture. The latter is unlikely to leach away in a hurry, so may remain impregnated in the lime mortar and be a permanent solution (but not a solution, IYSWIM!).

[Brian Gaff]

I don't think that works, least not on a wall I have here it didn't. Gave up.. Brian

[Martin]

black!

If you apply too much moss killer you can kill the grass as well as my wife proved earlier this year.

[Dave Liquorice]

I had a niggling doubt in the back of my mind that moss was a "different plant" and glyphosate didn't affect it...

Ferric chloride any good? Got some of that for etching PCBs... From the ground there are only two small, as in a few inches long, places with moss. A squirty spot treatment would be ideal.

[Janet]

Next on my list; and application of sharp sand.

Janet

[Chris J Dixon]

Though, sadly, it is no longer permitted to be sold for this purpose. However, I doubt the environmental police can nick you for it .

Chris

[The Other Mike]

Pressure washer?

[Janet]

Well, not if you send us all a five pound note

Janet

[fred]

Cold water bleach plus a drop of vinegar. Despite having this ridiculed by a 'chemist' here, I have tried it and it works. It is the only thing that I have found to be effective. Tried numerous proprietary liquids and while s ome worked for a while moss always came back. Not with this.

Its used by laundries and I understand swimming pool cleaner is a similar p roduct.

I have also used chlorine tablets which are as effective if a bit of a nuis ance to dissolve.

I have only used it on a tarmac drive so do not know if it stains. It is ce rtainly toxic and gloves, mask and eye protection are recommended.

[Martin]

Serves Chris right for pretending he was Lobby Ludd when he bought the Jeyes Fluid.

[Dave Liquorice]

Nawp, the wall was pressure washed two years ago to remove the old flakey paint before being repainted. Last year one of the spots was scraped out and wirebrushed before being repainted. This year the damn stuff is back and the paint failed...

The moss must be well emeded into the stone/mortar so the treatment needs to get right down into the roots and kill them.

[David Hill]

That's why in times past graffiti was painted onto walls using liquid cow dung,it caused moss and algi to grow and couldn't be removed.

[Andrew Gabriel]

Well, Pathclear (a similar product) kills moss pretty instantly, much faster than it kills the plants.

Doing it permanently means changing the conditions to be unfavourable to growth, e.g. repointing and stopping gutters overflowing down it.

Lawn moss killers usually have warnings against getting them on stone/brick/paving, as they can stain permanently.

I found (by accident) that setting the mower one stop lower than usual caused it to rip out tonnes of moss, a much larger volume than the amount of grass cuttings normally collected.

I have used the combined lawn moss/broadleaf weed killers and fertilisers in the past. They used to be very effective, but the broadleaf killer in them is now much less effective (moss killer still works instantly).

[Jim Hawkins]

What is 'cold water bleach' and where do you get it ? How much vinegar per gallon of cold water bleach ? How many square yards will a gallon of the stuff treat ?

Jim Hawkins