Sometimes you succeed and sometimes you don't. That's just the way it is with gardening and you might as well be prepared for it.
This 4' x 8' bed is at the back patio and is full of dirt, compost, and some decaying leaves and chips. I decided that I would broadcast lettuce and carrot seed to try and get a good harvest before winter. So, I broadcast the seed and watered and watered and watered. It's been hot so the babying was a necessity. Soon the seeds germinated and were "thick as hair on a dog's back." I was pleased, so I continued to water them. Eventually they grew to about 2" tall and I noticed they were fuzzy. They were TOMATO SEEDLINGS! Argh! We had tomato plants scramble across this bed for two years in a row.
I got rid of the seedlings with a hoe and planted some fall starts purchased locally. Here we have green and purple cabbage, kale, and bunching onions. You just have to roll with it.