In article ,
"David Hare-Scott" wrote:

tibbar wrote:
'songbird[_2_ Wrote:
;954136']tibbar wrote:
....-
My question is can I use limestone chippings for the ballas it
appears to be the cheapest aggregate unless you members know better,
I'd appreciate any information.-

chipped limestone will have very high pH.


songbird

Thanks Songbird for your reply, does having a high pH make them
unsatistactory for growing tomatoes?

High pH in soil will reduce the absorbtion of some minerals which become
less soluble. Most veges (this is a generalisation) like it about 6-6.5
that is slightly acid and IIRC tomatoes are in that group. The question
that I cannot answer with certainty is will limestone chips in the aggregate
layer have the effect of raising pH too high. I am guessing there will not
be very much effect in the time that tomatoes grow as limestone chips will
not dissolve readily.

I take it that there is water in the aggregate layer. If so test its pH and
you will know and nobody needs to guess. A dye indicator pH test kit is
cheap and accurate enough for the purpose and will always be useful if you
are going to grow veges.

David

PH aside, this strikes me as a very dumb idea. I presume you've read the
Royal Horticultural Society's suggestions for Ring Culture.
http://apps.rhs.org.uk/advicesearch/Profile.aspx?pid=437

They basically say that the Family: Solanaceae is best for this
technique, but they never recommend it. You will have to water 2 to 3
times a week and there is nothing to hold the nutrients, so you may need
to fertilize with each watering. This isn't like hydroponics where you
can recycle the nutrient solution. With Ring Culture you add your
nutrients, and then it is gone. Washed away with the following watering,
if nothing else. That's lots of money down the drain.

My suggestion is that either you go hydroponic, or plant in pots with
potting soil (which will hold the added nutrients).

If you insist on doing Ring Culture, do it right, not on the cheap. I
presume gravel is what you would need.