In article ,
(Alan Holmes) wrote:


How long can I leave them in the ground before they go to seed?

I want some seed from the leeks, but I'm not interested in seed
from the celeriac.

If I have to dig them up, how do I store them?

(From a cached page on Google):

Leek -Seed Saving Instructions: Biennial. Leeks will not
cross-pollinate. Select only the best bulbs to keep for seed. Bulbs
will store very well at 32 degrees F. In milder areas they can be
mulched heavily and overwintered in the garden. Plant out leek bulbs
in early spring and allow them to form seedheads. As soon as the
seedheads start to dry, they should be cut off. Place seedheads in a
dry shaded area and allow to dry completely. Seeds can be easily
removed by rubbing seedheads between hands.

For celeriac, see:

http://gardenbed.com/A/400.cfm