[mdjlucan]

sowed 29/3 2012 the leaf is tall but beet root is small is it be-cos it was grown in mushroom compost or to much rain

[JayG]

I think the clue is "mushroom", but not the compost!

They look rather overcrowded so don't appear to have "mush-room" for the beets to swell to a good size.

If that is the case (rather than my interpretation of your picture) I would suggest thinning them out to give them more space (you can eat the leaves either in a salad or cooked like spinach.)

[Trillium]

Definitely too crowded in there and no room for the roots to swell up.

Also, mushroom compost is quite alkaline and could be holding back the roots as well.