Watermelons everywhere!

I mentioned previously that I had found a watermelon sprout near the peppers. Well, more have popped up.

Apparently the perfect weather has arrived for these things because everywhere I look I'm finding watermelon sprouts. When I re-used the soil, I didn't expect that the seeds were still viable. At this late stage of spring (because it sure isn't summer here yet) I wonder if it's even worth it to keep these seedlings.