Natural home herbicide

I need to remove a lot of wild parsnip and want to do it without chemicals.  Too much to dig, some will be mowed but some is in areas mower cant go.  What natural items can i spray on it to kill them???

Try some vinegar. It's a potent herbicide, especially if sprayed on a sunny day. Non selective, so don't get it on the plants you do care about.

If the parsnips are few and far between, you can chop them at ground level and put a spoonful of salt on the root. This method has been the death of many giant thistles at my place and it works on anything with a big taproot that tries to resprout.

They're a biennial so if you mow them before they set seed a couple years in a row it might make a big difference.  I assume...

Let them start to flower and then chop the flower spikes off, they flower and then die so do that a few times and you will get them. mowing takes several attempts but will do the same thing and kill them in the end.

I have a horrible "hay" grass that is invading my garden spot from the fields nearby for many years before I came along. Spreads by rhizomatous roots which can be as deep as 4 inches or more and still put up shoots because there is a green leaf somewhere feeding the whole complex mat!
Lasagna didn't work from last year because I didn't fully understand this habit. I did the best I could this year before planting potatoes and onions, but it's still coming up in there.
Will vinegar kill this? before it kills me!!