"Nick Maclaren" wrote in message
...
In article ,
Bob Hobden wrote:


Can't believe that there is so much difference in the soil in less than 2
miles and all within the Thames floodplain.

Your mind needs more exercise. Soil often varies in much shorter
distances than that - ESPECIALLY in such areas (e.g. here). What
happens is that an old river deposits some sand/silt/gravel/clay
or erodes some peat, and the next episode fills in with something
else.

Talking to another plot holder down there he said he put 5 cwt of lime on
his plot to bring it up to pH7.5 just to grow his brassicas (clubroot is
a
problem). That's an awful lot of lime, but then I haven't even started
putting on manure yet which will probably lower the pH even more if
that's
possible.

Heck, that's not even a trailer load. The stuff is dirt cheap,
the south of England being underlain by thick beds of it.

Mushroom compost is alkaline, and there is a mushroom farm locally that
advertise on our site, but I don't think it would make much difference to
this pH, it's so acidic. If it's not too expensive I will get a few loads
anyway, the soil needs some organic matter although it's full of worms
which
I take as a good sign.

That's because they add lime to it.

First job then is to buy a hand held pH meter as it's going to be an
ongoing
problem.

Well, maybe. I wouldn't.


It might help him to work out how much lime he wants to add in the first
place, and then check effectiveness.

As a rough guide, RHS recommends 190 gm/m2 Calcium Carbonate to raise pH by
half a unit (loam soil); 420 gm/m2 (clay soil); 140 gm/m2 (sandy soil). The
normal target is a slightly acid soil of 6.5. This time of year would be a
good time to dig it in. Probably not such a good idea to add manure at the
same time, because ammonia may be released, reducing the nitrogen content.

Me, I just chuck a few handfuls on and dig it in :-)