On 10/11/2017 10:37, Chris Hogg wrote:
On Fri, 10 Nov 2017 09:44:45 +0000, Muddymike
wrote:

Is there anything that actually kills moss and prevents it returning 6
months later? We have a long tarmac drive and large back yard that is
20% moss covered!

Mike

Plenty of stuff he https://www.rhs.org.uk/advice/profile?PID=418

Watering with a solution of sulphate of iron will kill it. It goes
black, as do your hands if you get it on them.

Your hands and any paving you get it on will go rusty orange (or at
least they should do). Silver nitrate makes hands go black. If you
express the same primitive moss green chlorophyll in your skin then you
would also go black so Dane Dare's Venusian Treens would be in trouble.

Bleach is another
alternative, as are the chemicals listed in the RHS page, above. Jeyes
fluid also works, if you don't mind the chemical toilet smell
lingering for quite a few days.

Jeyes fluid isn't a bad choice on tarmac, but better would be sorting
out the drainage and shading so that the path doesn't stay damp so long.

Benzalkonium chloride is quite effective on algae and other green
slimy stuff, but I don't know about moss. Probably cheaper if you buy
it as a concentrate on e.g. Ebay rather than as a branded and diluted
algae killer. https://www.ebay.co.uk/sch/?_nkw=ben...ium%20chloride

The choice is between fixing the actual problem of bad drainage or
treating the symptoms regularly with fairly persistent chemicals.
(or learning to love moss as the Japanese gardeners do)

--
Regards,
Martin Brown