Posted: 13/01/2016 at 20:43
If it were me, I would dig out as many of the weeds with roots that you can, or wait until they start growing in spring and then spray them if you want to use chemicals.
I would cover half of it with weed membrane. You don't need to add soil to the top, but you can cut holes in it to grow lots of stuff through, whilst suppressing the weeds. I have done this successfully for courgettes, squashes, pumpkins, sweet corn, potatoes.
Any that you leave bare, keep weeding throughout the year, to get out all the weed seeds that germinate.
The beauty of veg growing is that it is all annual, so yes, weeds will grow, but as well as weeding throughout the year as the veg grows, you can also give it a good dig over at the end of every year to get any perennials out.