Any idea for DIY soil mix for growing parsley?

I purchase an organic blend from a local nursery. Any good bagged potting soil will work. They will state for herbs and vegetables on the bag. Here are a couple links.

https://www.gardeners.com/how-to/herb-garden/5068.html

https://bonnieplants.com/library/you-must-use-a-good-potting-mix/

I use one of the better potting soils with peat moss added for all my potted veggies, herbs and flowers with good luck. I also add this to the holes I dig in the soil when I plant in my garden. I double the size of the hole and mix this in with the soil to give the roots an extra boost.

1 part each topsoil, peat, compost and pearlite, add fertilizer according to package directions if not using to start seedlings.

There are commercial mixes for herbs, vegetables, and things at your local nursery! Go, look, see what's in those, and just mix up your own! Try GOOGLE -- dirt requirements for PARSLEY ... happy harvesting!