[AlaninCarlisle]

I have two main veg patches. One in front of my polytunnel that is really reclaimed pasture, quite clayey, despite copious amounts of manure over the last six years since I created it. The soil is just about a spade-spit deep and below that is clay and pebbles

The other is good loamy soil that has supported veg growing since we moved here 35 years ago. It has also been well manured. The depth of soil is around 2 ft.

Both plots get approximately the same amount of sunlight and rainfall

However the growth habit of everything in each of the two plots is totally different. The newer bed by the polytunnel produces veg such as leek, parsnip, celeriac that are far squatter than the other bed. The crops are much fatter and shorter than those in the older and deeper bed.

Is this an obvious result of differing depths and types of soil?

[New shoot]

I reckon it is.  Underneath the main edible part of all of those crops is a tap root or small feeder roots.  If they have deep soil to go into, they will willingly grow into it. 

Show growers use very long planters full of compost to grow their monster veg.  I know that is an extreme, but when you see the extended length of the root on a show parsnip, it it amazing.

[snowdrops]

It sounds like over the years you have proved your own theory so I see 2 options, either make the veg beds by the tunnel into raised beds, how high is up to your budget & how much Work you want to undertake or alternatively plant crops with less need of the deep soil. Have you tried beans,lettuces,onions etc there?

[AlaninCarlisle]

Oh, I'm happy the way things are. Not growing parsnip etc to show, just to eat.
I was just intrigued by the marked differences in appearance of root crops between the two beds

[Yorkie]

It's probably also worth considering varieties of root veg that produce shorter, more stumpy roots naturally if growing them in that space.

[snowdrops]

Oh, I'm happy the way things are. Not growing parsnip etc to show, just to eat.
I was just intrigued by the marked differences in appearance of root crops between the two beds

Ahh sorry I misunderstood, I’m always intrigued by how much a row of something can vary, from little or nothing in places to great big produce in others. I once grew a huge swede with a girth of I think 19 inches in a row of quite small ones, never knew why, thought it must have had a dead dog under it lol

[Mr Dog]

I've never really observed much difference in shape or size (apart from those mentioned by snowdrops), but taste yes. On my old plot tomatoes were definitely much sweeter than those from my new and unlike the side by side taste test I was able to do with those I have no direct comparison on potatoes but am pretty sure they had a much better, stronger flavour from the old.

[jambop]

The top soil in my garden is very shallow over nearly all the area some time only a spades depth but I still manage to get great crops out of all the areas. I actually think that the sub soil is quite good in terms of its fertility because deep planted vegs like leeks do very well, it is however very compacted compared to the topsoil. The soil here is, I think left from glacial times and can be full of round polished stones of varying size. The old houses here are built from these stones and weak lime mortar made with earth. My garden has been part of a very old, but small, farm for about 150 years ... there is not a stone in the ground... but you don't need to go far to find fields where every year tonnes of these stones are ploughed up. What my veg plot actually needs is a deep digging to break the sub soil and create some new fresh top soil ... a deep ploughing would be better but it is not going to happen in my time here