Got near a hundred mini watermelon this year, the very late ones were no good but for a couple months they were glorious. Mini love variety, it was a brutally hot summer and they flourished, I let them take over the whole garden.
Two plants survived being overrun by watermelon, the asparagus and the hong tsoi. I'm sort of resting it until "spring" which is planted around Feb here.
I only planted about 6 seeds and got nearly 100 melons, this was an exceptional year for them. Probably 25% loss because it flooded eventually and of course a few tried climbing and they are too heavy for that. Usually I get maybe 25-30 over the whole season.
They are so sweet that even after it started raining daily they were still great. Such a sturdy variety.
One plant per sq foot I can't imagine. Compact for a watermelon but they still sprawl, and pollination gets better and better through the season, bees were still trying at the end.