Perfect example. Back in February (I think) when I was starting a large batch of seeds for the spring they included this Yellow Granex onion. Knowing it would need a good amount of space eventually I started the seed in a grande Starbucks cup (16 oz.), intending to transplant it to a proper container at some point.
Well, I had so many seedlings going and so much craziness, that several green children were...well neglected. I didn't have a place to put all of them, gave some away, put off transplanting, etc. A few others are still growing in larger temporary containers, a couple are still struggling in their original paper cups because just I never got around to making a place for them.
Flash forward to yesterday when I finally got aroung to cleaning up my back door 'patio' area where I store my seed starting stuff, intermediate transplant containers, empty pots, and young seedlings. While tossing out those who could no longer be saved and those who'd already passed on to make a place for starting my fall plants next month when I found the above onion. I'd completely forgotten about it. It only got water because it was below something else I was watering that drained down onto it. It was getting a minimum, if any, direct light. It was still in the original seed starting cup. And this darned onion still grew into something I can eat!
No, it is not the big 'ol yellow onion I was intending to grow, but neither is it something to sneer at. This baby is gonna make a pretty good addition to one of my meals. It also cements my desire to continue growing this variety of onion.
That's it. You don't have an excuse to not try growing an edible now.