Celery was the hardest to get started. I tried starting it indoors first, when that did not work I decided to just plant the seeds in the garden. I sowed the seed at the end of March and when that pack did not grow, I sowed more seed in August for my fall garden, which still has not come up.
The celery in this picture http://fav.me/d3euq5h was from the first pack that was planted and did not come up until February while there was snow on the ground, almost one year later.
* The Monarch butterfly was added for effect in photoshop.