I planted seeds early couple year ago. They grew fine. And have also bought some plants. Put them out and covered with milk jugs. Had parsley mostly for the butterflies. I like to mix some with spuds and noodles.

Good question, Maude. I had poor luck with parsley seeds last year, but they were a couple years old so I blamed that. Now this makes me wonder if that was the whole story or not. Hmmmmm.... How does it reseed itself so readily but different times when I've tried to plant it, I've had bad luck?

One issue may be the quality of the seed. You might want to try a germination test on your seeds before you go to the trouble of planting them.

To make sure I get some plants I overseed the area where I want them either in early fall or early spring. If too many plants sprout I transplant the excess. I've never had luck with growing them in pots or trays.

Rhoda

Parsley takes a long time to come up 2 to 3 weeks. I don't do anything special for them. Just keep the soil moist by covering with plastic. I start some every year. They dislike transplanting___have a tap root, but I usually have plants big enough to start "stealing from" soon after setting them out.
Parsley is a biennial. On rare occasions I have had some winter over and flower and set seeds the second year.
Here, if you cover your plant in the fall when the first killer freezes occur____mine is up to the south of the house____you can have fresh parsley until Thanksgiving. At Thanksgiving I cut some and put it in a jar in the ref. with just a little moisture. Am still using from it now. It's a tough bird.
Last year the seed I used was 3 years old. Started it earlty in case nothing came up, but I didn't have to buy any new!!

I just ducked into this Forum to see what IronBelly was writing recently and saw this question. As a long time (former) northern grower let me suggest a method that always works. In the fall, stake the spot where you want to grow parsley. Then, as the last snow of the winter (hopefully) is melting down, toss the seed on top of the snow in the selected spot. Parsley is slow germinating. If you have sown fresh seed it will germinate. Give it a try.