In article ,
Indigo wrote:

I've got several quite old terracotta pots that were given me by an
elderly gent who'd once been a market gardener. They all have single
good drainage holes and I normally put a flattish stone or a bit of
broken pot or polystyrene packing in the bottom, mainly to stop compost
falling straight out or washing through, rather than for extra drainage.

Yes, that's why you do it. A bit of broken pot is much the best,
as you don't want to seal the hole.

Saw this: http://www.bbc.co.uk/news/blogs-maga...nitor-27126160
and wondered if I should really try something else - bit of old cotton
cloth or something? Used tea-bag?

This article from last year by biologist Ken Thompson is on the same theme:
http://www.telegraph.co.uk/gardening...otty-idea.html

It is they who are potty. Older pots had quite large holes, and the
soil loss could be considerable - indeed, if it were a sandy mix,
it could be near-total. Also, if used judiciously, a bit of curved
broken pot can increase the effective size of small holes.

Obviously, you can also block holes, especially when using flattish
items.

So do you crock or not?

When appropriate. But I also usually put a layer of lawn moss on
top of the crock (or bottom of plastic pots), which reduces mess
and increases drainage. As it also holds water, it is ideal for
the purpose, and I often find that the roots are thickest in the
moss.


Regards,
Nick Maclaren.