I probably should provide an update to this thread... I've now completed my third year of transitioning over to using Kincaid metal markers (stainless steel posts and plates) labeled with Brother PTouch TZ tape (outdoor rated).
I can't imagine using anything else now. They are easy to read. The 3-year-olds don't show the slightest bit of fading or wear. I do put the posts deep into the ground (so the plates are close to the ground) but they have all stayed in place, resisting movement by small animals and frost heave. I haven't had any problems with them whatsoever. Really like them a lot.
I've been using them for seedlings too. To save money I on average use one marker for every two seedlings. There's room for two lines of text on the plates so I typically use the top line for the first seedling and the second line for the second seedling. I put the marker directly behind the first one and I use a "<" or ">" in the second line as an arrow to indicate where that second seedling is relative to the first one. Can get a bit tricky when one of the two is composted but I've been finding ways to deal with that...
