Posted: 19/09/2013 at 12:58
Hi, re celeriac. They need lots of water and potash based fertilizer. It is not advisable to grow them near carrots, fennel, parsnips or parsley. Do not harvest before end October.When the tuber has reached the size of a walnut, remove so much earth around the tuber so as to expose the upper roots. The development of the tubers is stimulated by the drying up of the upper roots.
Can't help you with the beetroot I'm afraid. I grew them once and they were all bitter, so never tried again!