We have Sown and grown carrots and Parsnips in the same way for several years now. We create a shallow trench through weed control fabric. We then fill it with compost and sow the seed in a drill made in the compost. The sowing area is them kept well watered. These are then protected from carrot fly by creating an enviromesh tent. (This isn't really necessary in the case of parsnips but the length of mesh is such that it stretches the whole length of the bed. It also gives the sowing area some protection from any creature that would otherwise walk all over it).
We don't do any thinning out preferring a survival of the fittest strategy and we don't really mind bizarre shapes. We do, however sow the parsnips more thinly than the carrots.
Last year our parsnips - Gladiator - performed really well. Germination was excellent.
The parsnips Seedlings grew on to produce a good crop of healthy decent sized roots.
So some were odd shapes and none would win prizes but we grow to eat and these roots fulfilled our requirements. I'd say that it was out best parsnip harvest but have no idea what made them grow better this year.
Despite many plot holders on our site declaring that trying to grow carrots here is a waste of time, we always seem to manage to harvest a good crop which carries us through winter.
This year we started out as usual and even applied nematodes to the carrot bed as an extra level of slug protection. The carrot and parsnip seeds were sown on 21 April and all seemed well as they began to germinate.
Unfortunately Slugs moved in and mowed off the lot. The slimy pests seem to leave parsnips untouched. Not to be outdone we resowed on 26 May and exactly the same thing happened.
It looked as though we would have to resign ourselves to a carrot free year. We decided to make a final attempt to beat the slugs and bought a couple of early carrot varieties - Amsterdam Forcing and Early Nantes. The basis for this choice was that we hoped early varieties would mature quicker as at this point it was the end of June.
We also decided to sow in a different area of the plot. The seed was sown on 26 June and as time was limited, a piece of enviromesh was just laid across the seed bed. No nematodes were applied.
The Seedlings Grew quickly and the mesh was loosened to allow space for the seedlings to push it up as they grew.
This time the slugs stayed away and we eventually achieved a crop.
So now we are left pondering some questions.
Why was the slug attack worse than usual? Did the wet March have a knock-on or did the previous mild winter cause a population explosion?
Why did the nematodes have no effect?
Why didn't the slugs move in on the June sown seedlings? Was it because the enviromesh was close to the ground? Didn't they like the feel of crawling around under it?
If you are interested our sowing method for parsnips is shown in more detail here and carrots here.