It takes 1,800 grapes to weigh as much as one watermelon. Together, these grapes weigh 19.8 lb (9 kg) and form a heap about half the size of a 5-gallon bucket.

To weigh as much as a watermelon
about 1,800 grapes
19.8 lb (9 kg) each side
about half the size of a 5-gallon bucket
Sizes and weights are typical for an adult or standard grape; real ones vary.