Carrot towers; an experiment in intensive growing

My little Purple Dragon carrot seedlings are growing up so fast so I thought it was time to start experimenting with ways to grow them.

We have no topsoil here at all (well a few centimeters in some places) so I have been thinking about raised beds for carrots for a while, then I came across this idea, called a flower tower and thought "Why not try it with carrots?"

As you can see, I built the frame as per instructions (see the 'flower tower' link)

Then I found a stray piece of PVC pipe and thought it would make a good water delivery system.

So out came my trusty drill

Dozens of holes were randomly drilled all over. I also plugged one end with a sink plug.

The pipe went into the middle of my frame, plugged end down.

Then I filled the lot with potting mix and compost.

I also added some PVC pipes through the bottom, sticking out about 25cm, to provide supports for the cover.

The seedlings were poked through the shade cloth into the potting mix. A job which took ages.

I planted a tomato and a love-in-a-mist in the top to provide colour and shade to the carrots (and maybe even tomatoes)

And marigolds around the base, for companion planting and for more colour.

The wire cover went over the whole lot and the seedlings watered in

Then I added an old sheet over the cover because it's a windy, hot day and the little seedlings need all the cover they can get for a few days.

The result so far is a mysterious, sheet covered mound. I have some concerns about this method;
If the carrots grow straight down, will I be able to harvest them?
Will I be able to keep the water up to them?
It is a time consuming business, putting the carrots through the shade cloth, is the yield worth the time?

I only planted 10 carrots in the tower as a trial run, but if it works there is room for 50 in just this little tower so the method certainly is space saving.

I will keep you posted on the progress of this experiment.