This is my *best* soil:
http://i.cubeupload.com/ixJt7h.jpg
It's half stones:
http://i.cubeupload.com/czWmKi.jpg

Hence two questions ...
Q1: Is your soil rocky like this?
http://i.cubeupload.com/lEPHQG.jpg
Q2: If so, how would you fertilize it?

The wife wanted planters for the grandchildren to put their food in so that
the kids could revel in the wonders of tomatoes and melons and peppers
grown from their own leftovers.

So she asked me to get her a couple of 5-gallon buckets of "soil" (she
called it "dirt" but dirt and soil, I was told by my college professors,
are two different things - but no matter how many times I tell her the
difference - she still calls it "dirt").

I went to the lowest area of my property to find the most non-rocky soil I
could find (yes, "rock" is different than "stone", as outlined by the same
college professor); but even then, thousands of feet away from the
bulldozed areas, I still ended up with 100% Franciscan sediments currently
weathered to 50% stone and 50% smaller particles.

I sifted out with a quarter-inch grid the smaller particles, but the result
is still a coffee-colored mix of what seems to be relatively infertile
soil.

How would you fertilize this stuff sufficient for kids to grow plants?
http://i.cubeupload.com/KlXcvs.jpg