Here in the Mid Atlantic the winters are normally mild compared to the rest of the country. Therefore many plants are easy to grow as late fall crops or for over wintering for early spring harvest.
The USDA Plant Hardiness map has Richmond VA at a Zone 7A (temp lows are 0 to 5 F). The map can be found at http://planthardiness.ars.usda.gov/PHZMWeb/
To increase my winter plant's chance of survival and harvest, we cheat nature a bit.
We have a hoop house that fits over the regular garden area and a hard poly-vinyl sided greenhouse. I typically use the poly-sided green house to start seeds and the hoop house for growing larger plants. This is because the hoop house is larger and having the plants in the ground gives them more insulation and more room for roots. Meanwhile the poly-sided green house is mostly shelves and a gravel floor. But the shelves are great for seedling trays.
I have had good success in prior years with a variety of plants in the hoop house in the winter. Interestingly these plants have proven hard to grow in the hot summers of the mid-Atlantic. These include many cold hardy plants such as kale and cabbage. Bulbs such as garlic and onion do very well in the hoop house too. Chard and spinach do not seem to grow during the winter. However, the plants benefit from the early start they get from being inside the hoop house. The hoop house will help ensure early spring chard, spinach, garlic, and onions.
The hoop house normally goes up the first week of November. My earlier posts recalled the first year mishap with the wind. (The hoop house was upside down on the patio at 2 am). Learning from this we had the stakes ready this year. The first night we had the hoop house up we again had gale force winds like the year before. This year the hoop house went nowhere!

Please note the big stake in the front of the picture!
We also improved the door. Last year the door was a simple flap with a frame to help keep it sturdy. This year the hoop house has a hard sided end with a sliding door. This door stays shut allowing for better insulation and reducing the wind that can get into the hoop house.
It is important to make the swoosh sound when opening and closing the door.
It –uh-- makes the plants grow more efficiently?
No that - um - makes the hoop house look more high tech?
Below is a picture from the outside.
And an excellent example of how to reuse broken shovel handles!
This year we also had a plan for planting! I will admit that the hoop house last year was placed over plants already in the ground. This had some drawbacks later as we noticed some plants prefer different areas of the hoop house.
So this year I started the seedlings in the poly-sided greenhouse and then planted them in the ground inside the already in place (staked down) hoop house. Cold loving plants like Kale are on the outside while the chard and spinach are on the inside. The cabbage has plenty of room in the back of the hoop house.
Below from left to right are:
garlic sprouts
kale sprouts
onions
red cabbage sprouts
So this year I started the seedlings in the poly-sided greenhouse and then planted them in the ground inside the already in place (staked down) hoop house. Cold loving plants like Kale are on the outside while the chard and spinach are on the inside. The cabbage has plenty of room in the back of the hoop house.
Below from left to right are:
garlic sprouts
kale sprouts
onions
red cabbage sprouts