Police are appealing for witnesses after the eco greenhouse at Priorsford Primary School, Peebles, was damaged last Friday.
The incident is believed to have taken place between 4pm and 5pm.
Community Beat Officer PC Mark Halliday said: “This was a really upsetting for the children who had put such time and effort into creating the greenhouse.”
Anyone with information should call 101, or through Crimestoppers on 0800 555 111.”