The white specks are reminiscent of spider mite damage. Check closely under the leaves for tiny moving specks, white chaff, and eggs.
Rust marks are usually calcium deficiency. Since you only have a few- it's hard to say for sure. I wouldn't worry about it too much yet. You bigger issue is the clay soil and always will be.
That (Ca def) can show up as white specks in its earliest stages as well, I believe, but the times I've had white specks from deficiencies, they weren't so small or so numerous- and didn't look so much like spider mite damage.
Rust marks are usually calcium deficiency. Since you only have a few- it's hard to say for sure. I wouldn't worry about it too much yet. You bigger issue is the clay soil and always will be.
That (Ca def) can show up as white specks in its earliest stages as well, I believe, but the times I've had white specks from deficiencies, they weren't so small or so numerous- and didn't look so much like spider mite damage.