David Hare-Scott wrote:
....
A photo would help but it's probably algae. There isn't much you can do
about it unless you want to spray a lot of chemicals that will have
substantial side effects. It will reduce in dry weather and grow in wet.

Instead of trying to eliminate the algae it would be easier to adjust your
expectations of what a garden should look like. Gardens are full of bugs,
bacteria, fungi, algae, spiders, grubs etc, the list is endless, which
superficially are not desired. Some turn out to be beneficial and all have
a role in the ecology. You can spend your life trying to beat them (and
inevitably fail) or recognise that is how the world is and reach a
compromise. The compromise might need to be more in your favour (say) where
a horde of birds are about to eat all the fruit that you wanted to eat but
it might be more in favour of the natural result in matters that are not so
important.

David

PS

South West of what? This is an international newsgroup.


i'd assume it was moss or algae, if it's spring
it could also be pollen.


only in the last case does washing do much
good. if algae, it will die back when it
gets dry again. if it is moss, leave it alone
and enjoy a beautiful mossy garden. well worth
leaving alone... if the climate is nice enough
you can find bits of other mosses and include
them in a patchwork pattern.

moss and algae are in the air so there's no
way to get rid of the permanently. chemicals
will knock it back for a while, but the
poisons or changes to soil chemistry are not
worth the use.


songbird