crushed oyster shells as potting soil additive?

 Wondering if anyone has knowledge of this.

I bought a bag of smashed oyster shell chicken grit from the farmers
coop.  Chicken grit has been recommended as a good way to increase
drainage for young maples in pots.  (I also use sepiolite or other
mineral cat litter to hold water, oxygen and make rougher structure.)
But they may be talking about gravel, not shell.

I'm worried about increasing pH or getting too much calcium to the roots
as some of the mix is quite dusty, although most pieces are several mills.

Am I worried for nothing?  I potted up 10 good 2 liter palmatums as an
experiment, but actually I'd quite like to use the stuff and not have it
sit around for a year...

Thanks,

-E

 

It is lime (calcium carbonate). Just keep it away from your azaleas.

 says...

  I use shell grit (from the beach, rinsed) but only on lime lovers like
clematis and brassicas.
  For potting acid lovers I buy a sharp grit from the gravel quarry.

  Janet.

 On 11/02/2011 07:18 PM, Janet wrote:

My hope was that the shell grit would be coarse enough that it would
only slowly leach into the soil.  I didn't look closely enough to see
that there was lots of powder in the bag...

Lucky you to have a gravel quarry at hand!  The shell is cheap, about
0.80 EU/kg, as opposed to fine aquarium gravel -- which would do the job
admirably -- at around 3 EU/kg.

Most maples, including the Japanese varieties, are not particularly acid
loving, contrary to popular opinion.  They do fine in neutral to lightly
alkaline soil.

Our soil is naturally quite acid, 5 to 5.5 depending on the spot.  So we
don't have a lot of lime lovers.  I guess I'll need to give the shell to
someone who keeps chickens.  Probably get a few dozen good eggs out of
the deal, anyway!

-E

 
  It's an interesting place to visit and see how they work and the
different grades of product extracted.They used to sell sand to Saudi
Arabia (for water filtration) :-)

   Janet