How to concoct "gravel with clay base" for cabernet vine?
I did a lot of research and found my Cabernet grape vine needs gravelly (quartz based) substrate, with a clay base. The roots go deep through the gravelly dirt part to get to the nutrients below. The clay drains but also retains moisture. I have a perfect all-day sunny spot and a proportionately taller pot to put it in.
But how on earth (pun!) do I make gravelly soil with clay? In your long container gardening experience, how would you do this?
Can you put it in paint-by-numbers terms? I'm stuck on the actual parts I need and how to put it in. I guess I will be getting things from the building materials dept at the home stores.
ps. If the vine already has tiny grapes all over it, should I wait until season's end to repot it? Or is now fine?