My sympathy Regenbogenschnecke,
i planted a bamboo over 2 years ago and realised it would be very invasive. I dug it out (or so i thought) and i am now still digging it out. However it is getting easier. When i see the new growth i pull it and the roots now seem to be nearer the surface. The roots come up quite easy now. I pulled a lot up at the weekend.
If you think you have got most of it out it shouldnt be too much of a problem. You can give it another good dig before you put your crops in around march april time.
Good luck with your veggies and i look forward to seeing how you get on.

__________________