There is a watermelon farmer in Houhai Reclamation Area, Daitou Town, Xiuyu District, Putian City. The watermelon variety planted there seems to be called "American Landmine". I went there once last year. Small, but the skin is thin and sweet. You can take a bus to Daitou Station, and then ask the watermelon planting area in Moto Houhai. If the motorcycle knows, get on the bus. The fare is about 4, 5 yuan!

I hope it helps you!