Much of the soil is aluminium-in clay etc. It is the most abundant metal in
the earths crust(8.1%) Above pH 5 it will be quickly weathered into the
soil, effectively becoming a mineral constiuent of the soil. It becomes
progressively more soluble at lower pHs where it becomes a toxic
constitiuent of acid rain-soluble aluminium amongst other things deposits
aluminium hydroxide on the gills of fishes and was suspected of causing
damage to the nervous system.
Aluminium at pH 3 to 4 is sprayed all over the place in antiperspirant
sprays. I guess aluminium sulphate (pH around 4) coalgulates the slime layer
on slugs.
regards
David T

wrote in message
oups.com...

Rupert (W.Yorkshire) wrote:
wrote in message
ups.com...

La Puce wrote:
H Ryder wrote:
Do you find it works?
haven't actually tried it here this year yet but it certainly worked
previously on my heavy, sodden clay in Cheshire. I was under the
impression
that slug pellets left poisonous slug remains which killed birds and
frogs
etc which I wanted to avoid so, after trying and giving up on all
the
various "safe to other wildlife barrier" methods, I tried nemoslug
and
found
it worked well, even when applied at slightly less than the
recommended
rate. I also found that it seemed to last longer than 6 weeks.

I'm waiting for my nematodes (megatoads as my son call them) to
arrive.
I thought it only worked on baby slugs not the adult ones?! Also
there's two applications and the Organic Catalogue will dispatch the
first lots and 6 weeks later the second lots so that I don't use it
all
at once. I thought that was really considerate of them )

I also thought some slug pellets are only ferrous phosphate and that
it
breaks down to iron and phosphate nutrients in the soil?! Are they
not?!

I use aluminium sulphate ones and you can get ferrous phosphate. These
work for me and are hopefully fairly harmless but I still use them in
small amounts and not near vegetables. The blue ones are metaldehyde
and possibly much more toxic but I do not actually know. I do not use
them anyway.

Des in slug ridden Dublin


I am having a crack with the Nematode things this year but AFAIK they
only
work on slugs and not snails.
The Ferrous phosphate stuff is fairly harmless and is used medicinally
for
folk with iron deficiency.
Aluminium sulphate. I don't know about the cumulative effects of
aluminium
in the soil /veg.
The dreaded blue pellet things are, as you say, metaldehyde. I thought
the
main objection to these was that the dead slugs get eaten by other
birds/animals and get ill/dead.
Here is the other side of the argument
http://www.gardenseeker.com/slug_pellets.htm


I am still wary of these pellets. Everything on that site was worded
so carefully that it reminded me of political spin. They could be
right but I would like to see independant work. They quote one
hedgehog who ate lots and was grand afterwards which does not fill me
with any confidence.
The alu effects on soil, I am wary of and that is why I use very little
and only for me cardiocrinums and a few other odds and ends. I woul
like to try the ferrous stuff since, as you point out, it is likely to
be harmless.
For the greenhouse, I am currently using beer traps and orange skins.
I left it too late to use mini-cloches as me tomatoes are now too big
to fit.