Zucchini Explosion!

I thought my plants were acting weird because I had a bunch of little zucchini's and they weren't getting big fast. It seemed like last year, once they appeared, they grew to full size over night. Well, I was wrong because I didn't look at them for a couple days and now I have HUGE zucchini's!



I put an envelope in there as a point of reference as to how big they are:


The bottom one is a cucumber...