Years ago, I was riding on a bus to downtown, and I wasn't sure how to find the place I was heading. I got into a conversation with someone who told me that my stop was right before his.
He told me to just get off one stop before him, and I would be fine.
I guess I was supposed to watch him get off, then get off one stop sooner???
This is kind of like when you read articles and they say, "Harvest your herbs right before they bloom."
Unless you are psychic, how do you know when is "right before they bloom?"
There are certainly some signs, that will help you to know, the stems will start to toughen up, you may see some buds forming, but you may also walk out one day and find out that your herbs are in full bloom, and you never saw it coming.
What do you do then? Is all your hard work lost?
Of course not.
Most herbs, and I stress MOST, can be harvested after they bloom as well. The difference is that once the plant blooms, more of the energy and nutrient of the plant goes into the flowers and less into the leaves, so you wont have quite as flavorful an herb.
Nettles will tend to get bitter once they bloom, and chives and other onion family plants tend to get tough and woody when they bloom.
After they bloom most herbs are still good, but the leaves aren't quite as tender, and aren't quite as flavorful. You may have a few tough leaves to discard.
But don't worry, don't despair, don't let a few flowers deprive you of the enjoyment of your herb harvest.
As you get to know your herbs, you will recognize the signs that they are getting ready to bloom. Until then, there is no reason not to continue to enjoy them.
Just take a minute to stop and smell the flowers.