Less agriculturally-minded folk than Mitchell Posin might mistake the sign on South Road advertising compost tea for a joke, something dreamt up by kids searching for the world’s least appealing beverage to flog by the side of the road.

In fact it is there to promote the result of three years’ trial and error by Mr. Posin, the co-owner Allen Farm sheep and wool company: an organic fertilizer solution for the bespoke ecology of Martha’s Vineyard.

For those still trying to figure out what to do with all those leftover coffee grounds and egg shells, there is help. This weekend Felix Neck and the Polly Hill Arboretum are hosting a compost tea workshop with Ann McGovern, Massachusetts Department of Environmental Protection’s consumer waste reduction coordinator.

Wow, that’s a mouthful. Perhaps a bit of composting is in order for Ms. McGovern’s title. Like maybe, Lady Who Turns Garbage into Garden Gold. Yes, that’s more like it.