A little while back, I planted six potatoes. They were all from the same bag, they were all roughly the same size, they all had about the same number of "eyes," they were all planted at the same time and in the same patch of soil within a couple of feet of each other, and they all received the same water, plant food, etc. at the same times.
Two of them never came up. One is large and in full bloom. Two others are about 2/3 the size of the large one and the flowers are about to bloom. The final one is about 2/3 the size of those and hasn't shown signs of flowering yet. Very strange.
Somewhat later, I planted some shallots and some winter romaine. The shallots just sprouted. The Romaine hasn't yet.
Today, I put in two hills of canteloupe seeds with three seeds each.