In article , wrote:

It depends why it is damp. Dig a hole a foot or two deep and check
the soil. You can actually measure the proportions of sand, silt
and clay quite easily. Fill a transparent, straight-sided plastic
or glass bottle 1/3 full of soil, and top it up to 2/3 with water.
Add a small amount of washing machine powder to deflocculate the
clay, and shake it well. That means thoroughly for some minutes,
until it is all suspended.

The leave it to settle. If I recall, sand drops out in under
a minute, silt in under 30 minutes, and clay drops out over the
following hours or days (yes, days). So measure the soil heights
above the base after a minute, 30 minutes and when the water is
clear. Anything floating is organic matter.

Make it 30 seconds for sand. In all cases, the boundary between
gravel and sand, sand and silt, and (slightly) silt and clay is
arbitrary. The clay situation is complicated by the fact that
it is both made up of smaller particles and has a different
chemical composition.


Regards,
Nick Maclaren.