So, I decided it would be much easier to make markers of my own. What's cheap, plastic and will stick up out of the ground? Plastic knives, of course!
I used a sharpie to write the veggie names and then made markers. They are all stuck into my garden now but it was too dark for a proper picture outdoors.
Of course, you can mark the handle instead of the blade if you're worried about safety, but last time I checked, plastic butter knives had trouble cutting butter.