With the new signs in place, the old ones paused briefly for a photo op on their way to the trash:
That’s eight months of weathering on MDF covered with indoor urethane sealant and it’s not as awful as I expected: the MDF didn’t actually disintegrate, it just collected some mold / mildew / crud.
A closer look:
The black paint survived surprisingly well.
I hadn’t paid much any attention to the edges, so they got covered with random amounts of black paint and urethane. It seems that’s where the disintegration starts:
MDF definitely isn’t the right material for an outdoor sign and I knew that going in, but it’s cheap and readily available, which makes up for a lot.
For comparison, they looked nice right after installation:
Ya learn something new every year around here!
The Smell of Molten Projects in the Morning 
have you considered a spring-loaded gate hinge?
The whole affair is owned by Vassar College, so the facilities are what they are. I’m a tiny gear on the perimeter of the volunteers running the gardening plots.
Signs? Yeah, I can make those. [grin]