I'm trying it this winter. I planted spinach (maybe in August) but it was pretty slow growing. Thanks to the warm winter, I was able to pick some in early December just to show off. It was very sweet. I have not provided any protection but here in NH zone 5-ish, we have a snow cover right now. Might be gone by the end of the week.

We already have a hoop house on the agenda for DH to build this year so next winter I expect to be able to harvest greens all winter.

I've had some lettuces here and there over-winter without protection. I grow parsnips so they stay in the ground all winter. Tnis year I left some rutabagas in the ground to see what happens, also some kale.

I plant my spinach around Halloween. And then I get a crop in early spring. I just noticed today that I have some spinach sprouts out there.

This year I also tried planting some lettuce seeds at Halloween. I did get some lettuce (and spinach) sprouts back in November or December - one of those unusual warm spells. But I don't see any lettuce sprouts right now.

When we lived outside Philadelphia, we used to grow turnips during the winter. I think we sowed them in September, and then cut the tops when we got a warm spell.

We've managed to establish a self-sown kale patch here. I haven't been down there since the last snow, but before that there was still food in that garden.

The thing to remember is that there isn't a lot of growing going on when it gets cold. So kale that we could pick daily and never make a dent in the patch during the summer is only good for monthly picking after the frosts hit.

Thanks everyone for taking the time to reply. You've all given me alot to think about.

defrost49, your comment about slow growth makes me think August is a reasonable time to plant. I've read that watering the soil and covering it to cool it down before sowing helps with germination in hot weather.

pixie lou, you don't plant until Halloween. An early Spring crop like you get is what I was thinking about achieving, but then mad gallica's observation that growth slows in cold weather makes me wonder if that might not be a bit late here in central CT. If I waited that late in 2011, I would have been shovelling snow off the bed in order to plant. But then back to defrost 49's comment that they have snow cover still in NH, and we here haven't really had much snow cover here all Winter, because Winter petered out after the Halloween blizzard. If next year is a milder Winter like this, lack of snow cover could be detrimental to the plants.

So I'm thinking I need to make successive plantings to see what works best, from August through October, which brings me to what I can remove from the Summer garden by August to make room. This is getting complicated!

I can't do a hoop house, but I can do row tunnels. Maybe I should mulch part of the crop and build a row tunnel over part of it and see how the two methods compare?

And kale. Hmmmm... No! I need to keep this entry into Winter gardening small to start with.......

I waited for the Halloween snow to melt before I planted this year - so I planted some time in early November. I wait until late to plant the seeds since I am trying to avoid sprouting before winter.

I use all raised beds. My "goal" is to get 2 crops per bed each year. Around Memorial Day I pull all my spinach and transfer the beds over to squash or eggplant.

I think there might be a little confusion over what you mean by over wintering. If you want a fall crop that continues into the winter, I think you need to plant by mid-Sept. The days are getting shorter. Even if you have some protection in a hoop house, there's not enough day light so plants go dormant until sometime in Feb. (I might have my times off, read one of Eliot Coleman's books to be sure.) There were other people in our area who picked spinach in December. I left enough for another meal but I also expect the plants to start growing again in the spring.
I expect that if you plant in Oct or Nov, your spinach won't actually germinate until spring. As pixie lou states, she doesn't want them to sprout before winter.

I planted sugar snap peas and spinach where I grew garlic so that bed was available. In October I planted garlic in the area where I had grown tomatoes.

What I originally meant was planting so that I would get an early Spring crop, and the reading I've done about that came from internet articles which I think were written by folks living in the Pacific Northwest, which is why I asked about doing it here.Those articles say to get a crop established and then cover it with mulch, which is then gradually taken off as the weather warms, so you have your spinach in, say, April.

I guess I wasn't clear because in my head I'm also turning over the season extension techniques Eliot Coleman advocates. I've read his stuff on Winter gardening and am hot to try them. I've also read an 1868 book by a gent named Peter Henderson who was a market gardener in New Jersey, and he describes a system of using big cold frames and hotbeds to do the same thing.

But I'm glad I was confusing, because you guys answered a question I had wondered about, which was what might be planted in Fall in order to have a crop start in Spring.

If I understand what you are saying, pixie lou does just that with hardier spinach and lettuce and then follows that with warm season crops in late May. That makes such perfect sense. I think I was mentally groping toward something like this, but am so over-thinking this that I missed it.
But defrost49, are you saying that you also plant peas in Fall which will germinate in Spring in the same way the spinach does?

biblion - I may be getting a bit off topic here. . . I have all raised beds in my veggie garden. And I'm trying to get 2 crops per bed.

In 4 beds I plant the spinach seeds in late fall - I target Halloween. I get a spring crop of spinach, then turn those beds over into squash or eggplant. In 2 or 3 beds - I used to buy lettuce seedlings (late March or early April) at the nursery, but this year I attempted to sow lettuce seeds in late fall. I'm hoping for lettuce sprouts in the spring. If I don't get sprouts, then I'll just buy seedlings again. I then turn those beds over into tomatoes.

In late March/early April I plant pea seeds. Since the pea seeds are so big they could rot in the ground if they were in the wet ground to long. Which is why I wait until spring to sow. When the peas start flowering, I then plant bean seeds under the peas. By the time the beans sprout and I have bean seedlings, it is usually time to pull the pea plants.

I also do a spring crop of pac choi - buy seedlings from the nursery. I've attempted radishes in the past - but I just dont' have luck growing radishes. Then I turn those beds over to cucumbers and chard. For the most part chard is the only "leafy green" I grow during the hot summer months. I haven't had much luck with lettuce, even when I try to shade it under my tomato plants.

I've thought about planting a fall crop of spinach - when I pull the summer squash plants. But have never really gotten around to planting the seeds in late August. Once I did plant a second planting of peas - when my beans were starting to produce. But my second pea harvest was minimal - enough so I could snack while out in the garden, but never enough to pick for a meal.

I hope some of this helps.

Two years ago some of my spinach self sowed, germinated and grew well into the fall. Those plants resumed their vigorous growth in the spring allowing us to enjoy wonderful early spinach. So, last September I intentionally planted spinach in several raised beds hoping to repeat. We enjoyed a few meals of spinach through late fall and early winter. And, because these raised beds have been covered with plexiglass over the winter and, due to the mildest winter I have ever seen here in Vermont, the spinach plants look great. Hopefully, they will take off as soon as the ground fully warms and we'll have lots of early tender spinach for cooking and salads.

No, biblion, I don't sow my peas in late fall. Sorry for the confusion.
This past fall we used a low tunnel to protect bush beans from frost. Our garden and house are in a low lying area so we get frosts earlier than some of our neighbors and it seems to hit around Sept 18 right when the beans are blooming. This time, with the low tunnel, they survived and we enjoyed several meals.
We toured the vegetable garden yesterday morning. The snow is almost gone. The spinach looks like it will revive once the ground thaws. Most of the leaves are yellow but the centers are a good green.
Last night the local farmer who uses high tunnels said they would have fresh greens for todays winter market.

Here is a link to a pic of the lettuce we overwintered this year under very low hoops - one layer of Agribon and one layer of white poly. We took the pic on March 11.

I read that Peter Henderson book as well which is what made me gave it a go.

I also have kale and parsley that are starting to grow again now that the snow has melted and spinach, lamb's lettuce and green onions that were planted fall 2011.

Here is a link that might be useful: Overwintered Lettuce

Very nice! I had hopes for my kale but apparently the deer thought it was tasty.