Need advice from cold-weather gardeners about harvesting through snow

I have been gardening in Wisconsin for 12 years. Every year I grow kale and other cold-hardy crops, and for the first few years I was always amazed at how long into the winter the plants would survive. Over and over, I'd think "Wow, maybe this year the kale will make it until spring!" and then over and over, there'd be some day that I go out there and find all the plants destroyed by cold. Then finally I read somewhere that kale can take temps down to ?15 degrees Fahrenheit (maybe that was 20) and then it dies. That explained a lot.

This year I have a bunch of collards, kale and brussels sprouts, and I successfully got them through a cold patch (low of 12) by covering them with sheets and blankets for a couple of days. I harvested all but one brussels sprout plant, lots of collards and all of the curly kale (small leaves because I had harvested heavily earlier) prior to our big snowstorm last week. Now, finally, here is my question:

My garden has been pretty well buried under snow since the 20th and I know it is a pretty good insulator. How good of an insulator is it? We've had very cold weather lately, with lows into the single digits. Do you think there's anything still green under there? I was busy with Christmas, and right now I'm fighting a virus, so I haven't had the energy to go out there and dig in the snow to try to harvest. I think I remember Eliot Coleman saying that he waited until afternoon when temps got above freezing to harvest crops in winter, but that ain't happening. The highs will be below freezing for at least the next week. I still have one brussel sprout plant, two Toscano/Lacinato/Dino Kale plants, and maybe three huge collard plants.

I'd love to hear from experienced winter gardeners--should I leave the buried garden be, or are my plants desiccating out there even with the snow cover? My impression over the years has been that what happens when they go from green to brown is desiccation, and being snow covered should protect them from that, but I'm not sure if there is some temperature below which they just up and die no matter what.

Just because there is snow doesn't mean that the temperature of the snow cant go into the negative degrees.
The snow also reflects alot of heat/sunlight and doesnot warm up.
It also takes alot more enerrgy to warm up than the earth.

The best option for you is to get a 2ft high poly-tunnel.
It warms up faster and absorb the heat, and protect from the drying winds.

This link has a list of winter hardy plants check it out and tell me what you think.
http://perennialvegetables.org/perennial-vegetables-for-each-climate-type/cold-temperate-east-midwest-and-mountain-west/

I think it depends on the type of kale. I have kale that was planted in spring 2011. It overwintered and grew well all this year and is still going strong. Here in Iowa the temperatures got down below zero last year and this. I did not water it this year either and it would not die. It is amazing. I just harvested some more buried in snow yesterday.

Fabrizia, that's interesting--what sort of kale do you have that has grown for over a year in Iowa? And, by zero degrees, is that Fahrenheit or Celsius? When you harvest the kale, do you make an effort to bury it in snow again afterwards?

"S," (odd to go by one letter, but there it is) putting up a poly tunnel at this point is a non-starter. The ground is well frozen. Have you any experience with harvesting kale or other vegetables through snow?

The link you shared is interesting--I've been to that website before, although I have not yet purchased that book. I'm interested in growing groundnut (Apios americana) and I think it would be good to plant some perennial brassicas, if I can find seeds.

While the tops of my Kale and Collards always die back once the grounds freezes solid, I have had some success keeping them "alive" through winter. One year I dug all the plants out before the freeze (roots and all) and threw them in the middle of a huge pile of fall leaves. When I took the leaf pile apart in the spring to add them to the garden, the collards and kale plants still looked like they did 6 months earlier. So for experimental purpose, I re-planted them in a new area. They produced the first salad greens of that year and once the warmer weather began, they bolted and produced a huge amount of seed that I was able to plant that fall. I wouldn't rely on them for a second season but when they do survive, save seeds and repeat the process. You're bound to get a super cold hardy plant eventually. Right?

I suspect if you have all your greens in one place you could just pile on a few feet of straw or leaves on them once they stop producing without digging them up.

If you're looking to harvest all winter then may I suggest a book " the winter harvest handbook" by Eliot Coleman. In it you can find a lot of useful info about growing greens and other veggies throughout the winter. A lot of it involves, row covers, cold frames, poly tunnels and greenhouses. In some cases a combination of those techniques has allowed him to harvest through even the coldest winter conditions. His farm is based here in Maine so I'm sure he knows all about cold weather growing.

Best of luck

i have a small unheated greenhouse but my pex from my wood furnace runs in the soil below it..i still have tomatoes growing in it..but they don't ripen well without much sunshine.

there is swiss chard growing in there and some other greens from a mixed greens packet..and they are strong and healthy...we have gone as low as about 15 overnights here..but usually it lasts all winter in the greenhouse (6x8 double wall plastic)

I have kale still growing outside, but the bunnies have eaten the bottom leaves off of it so it looks like lollipops..thought about cutting it down to the ground??

In the past I have had cabbage roots make it and regrow baby cabbage heads, but that was near my septic tank where there was some heat, haven't had it work in the garden where it isn't heated..so you might try some areas with some ground warmth..or a cold frame..or a small greenhouse or hoophouse

Check out Elliot Coleman. He harvests all year in a cold environment. Probably the simplest method would to get most things into a root cellar. Snow will accumulate on the roof which is fine. Shovel it away from the door and you're there.

what sort of kale do you have that has grown for over a year in Iowa? And, by zero degrees, is that Fahrenheit or Celsius? When you harvest the kale, do you make an effort to bury it in snow again afterwards?

Here is the story with this kale. My girlfriend planted it in my yard because her husband likes it and they don't have a good place to grow it where they live. She doesn't remember what kind it is. It might have even been a plant she bought at the supermarket. But then she kind of forgot about it and didn't pick much. I didn't like it so I didn't either. So it just kept on growing on its own. Then in the fall of 2011 I was really busy and so never got around to pulling it out in the fall. By the time spring rolled around it was still going strong. By that time I was pretty curious to see what it would do. I didn't water it because my water bill was already high and also because I found out that our water is treated with chlolormine and I didn't think that would be good to use on the garden. Both last summer and this one were abnormally dry. So as time went on I kept being more and more impressed with this kale and thought I should really try to get to like it. So I started using it myself and now I like it. It does taste better after a freeze.

Yes, I was referring to below zero Fahrenheit. I do not cover it or anything. It is just out there doing its thing and seems to be perfectly happy in the snow. If I was being fanciful, I would almost say that it is wanting to grow so it can convince me to eat it because it would be good for me, LOL.

I will try to attach a photo here.

In the past 2 weeks I have harvested thyme, rosemary, kale, cabbage and a few other Brassica.
However I am in zone 6/7 and other posters here might be in zone 8/9/10 so even if we have snow.
Its snow with a temperature of 30F-10F not snow at a temperature negative 10F, like what you have.

You could go with root crops they dont mind the snow.

Try lining the edge of your beds with rocks, big rocks, 50-100 pounds each, preferably dark in color so they warm up faster. I'm fairly certain I read that information somewhere in the permaculture forum.