Your best bet for getting good results with parsnip seed is to buy fresh, prepare the seedbed well – they like a fine tilth – and don’t be in too much of a rush to sow.
If you can wait until the soil’s warmed up, in March or April, you’ll see better results. Germination can take 28 days, so you’ll need to be patient!
I like to use pre-sown seed tapes, they’re a brilliant way to sow veg which needs careful spacing in order to grow well, saving a lot of thinning out later on. Another easy way to grow parsnips is to germinate the seeds indoors, between layers of damp kitchen roll.
Once you see roots and shoots, transfer the whole thing into the garden. Space the seedlings 6” apart along the row, tuck the soil around them and pop cloches or fleece over for protection, until you can see those sturdy, true leaves pushing through.