How to store vegetables overwinter

My Onions did pretty well this year, I'd even go as far as saying they are the best onions I've ever grown. Amazing to think that from that little bag of sets, I got over 25 kg of onions. These have been carefully laid out on a table in my shed to dry, with most of the soil rubbed off. I would like to tie them in strings, á la french onion seller, but haven't mastered this skill yet. They'll probably end up in one of those carrot string bags. Once dry the tops will be cut off, and we'll use the ones with thick stems first, as these won't keep as well.

Now to harvesting carrots and storage. They're not going to develop much more now, and want to get them before the slugs. I've heard that they should be stored in dry sand or peat, has anyone done this, and how long do they last?