Hi Hank so long as it is sharp sand and no builders sand should help - can't guarantee you'll get decent carrots of course.

Yes and no!

The sand is basically inert and mixing soil with it might not be the answer,it will depend upon the ratio of soil to sand.

Personally I would sieve/ riddle the soil to remove any stones etc, and mix it fifty fifty with the sand, but more soil to sand is better as this will hold fertilser better, say two to one!

Sand alone won't hold fertiliser for the simple reason when you water it you will just wash the fertilser out!

The other way is to do as suggested in this link;

http://www.thegardenersalmanac.co.uk/Data/Carrot/Carrot.htm

Thanks "both," I mean to end up with decent carrots eventually if it's the last thing I do !

How deep is the raised bed?

I aim for a bed at least 15" deep for my carrots, but if you grow the shorter nante types then depth isn't as important.
The eco friendly types will crucify me now but this is what I'd do.

Take out the top 6" of soil from your raised bed.
To the soil left in the bed work in 100 litres of peat that has been sieved to get rid of the lumps and then made into a potting compost mix with chempak potting base, or similar, and 100 Litres of your sand. Once thoroughly dug in, repeat the process using 100 Litres of each of peat, sand and top soil at a time, and keep on repeating until the bed is filled.
You will then end up with the ideal soil structure for carrots.
You then need some sort of netting structure to go over the bed to keep out the carrot root fly.
For following seasons, Teegee's web site says it all.

Not easy, but you said you wanted good carrots :)

Well I 'could' crucify you Scrmpyg. but just because I think it is wrong to use peat doesn't mean you can't suggest it! Teegee I've always understood that carrots, and parsnips for that matter, need a lean sandy soil - hence they grow them in huge numbers commercially up here. So why the need to fertilise? The book I tend to follow suggests not doing so and we generally don't - unless Bulba forgets and digs in compost in the autumn.

Mathematically speaking, if you have 1kg of fertiliser naturally present in a certain volume of soil and you mix in an equal quantity of inert sand to the soil, then you end up with half the natural fertiliser per volume. Not a good idea.
I'll let Teegee explain to you a bit more about soil structure as the sand in soil is not the same as that found in sharp sand, and why Scottish sandy loam is different to Norfolk Sandy loam.

Well first of all, let's get back to the question asked;

We are talking "long exhibition" carrots not commercial carrots.

Regarding fertiliser; because we are planning on growing in man made soil( for want of a better description) then we will need fertilisers!

With the sand based soils; there are basically two ways of growing exhibition carrots and they are;

Note; I use barrels so I will relate to them,but the same can be applied to any form of container, and I would term a raised bed as in this situation...'a container'

Method 1; fill container with sharp 100% sharp sand!

Form a series of conical holes in the sand by rotating a crowbar or similar to form the hole around 3"-4" in diameter at the top and roughly 6"-8" apart.

Once the hole/s is formed fill it with a pre- prepared sieved compost, many growers have their own secret recipes!

This can take the form of a slow release fertiliser this should satisfy each carrots needs for the season.

I can't remember the recipe I used,will look it out sometime.

Do not add extra nitrogen as this can cause hairy fibrous root systems!

All that should be required from then on is to ensure the SAND does not dry out, particularly if grown under cover!

Only water the sand, to water the core will wash out the fertilser!

Moisture will be transferred from the sand to the compost by capillarity

Method 2; this is basically what we have been discussing i.e. mixing sieved peat and sand!

Like method 1 fertiliser will have to be added, as peat and sand for all intents and purposes are inert!

The disadvantage of this method is; because the whole container is fertilsed compost the carrots can vary in width and length, whereas in method one only the core formed by the crowbar contains fertilised compost so this generally restricts the width of the carrot and increases the carrots length as it searches for sustenance.

Again do not allow the compost to dry out, but unlike method one where you watered the sand, this time it doesn't matter so much as the whole mix contains fertilser!

To answer Mg's comment on fertiliser, her idea of not adding fertilser is correct simply because the 'natural' soil will most likely contain some fertiliser from a previous crop.

However it is advisable to add a small amount of a high nitrogen fertiliser to replenish that that has leached out over the winter months.

This will be needed to encourage healthy foliage, without which you won't get your carrots!

So that's my slant on growing "long exhibition" carrots.

BTW mg this information was not taken from a book ;o))

It never fails to amaze me the quality and depth of the information available on this site - what wonderful and comprehensive advice, and not a book or a google in sight! Who needs 'em? :o)
My carrots too have had loads of very healthy, exuberant growth above ground level this year, but you need a microscope to see the orange bits! I shall arm myself with this, and do better next year! Thank you everyone, and thanks to you, too, Hank, for your timely question.

As with G above, I too am amazed ! Who'd have thought my question about the simple carrot ( which is obviously far from simple) would have deserved all this info ?
But to get back to S's question re my raised beds - they're about 18 ins deep and have never been trodden on.
But again- thanks very muchguys, i may just have enough to go on !

Do forgive me, TeeGee, but a fragment of your advice above had me smiling:

"Do not add extra nitrogen as this can cause hairy fibrous root systems!"

I (dreadful sense of humour, I admit) just conjured up the possibility of having to take a razor to the carrots before cutting them up for the stewpot.

Sorry.