At the school I teach at, we have a raised bed vegetable garden on the corner of the main field. I've just been given the project to handle, and even though I know next to nothing about gardening, I'm concerned that the beds are being over-watered because they are in the path of the sprinklers for the field. I've rarely seen the dirt dry in the year it's been there, and in some places there is a green algae-sort of thing growing on the top of the soil where it is perpetually wet.

I have to work around this somehow, but I'm not entirely sure what can be done because we cannot relocate the beds or change the sprinklers. Has anyone dealt with something like this before, or have any suggestions what I can possibly do?

Thanks!