Last year I tested several different varieties of lettuce, plus a few other greens, to try and determine just how much cold weather they can take. I grew the lettuce and greens in my cold frames, which were covered with spunbonded polyester row cover fabric (like Reemay or Agribon). If you are interested in my cold frames, you can read about how I make them here.
The light row cover material works here in Southern Indiana because we rarely get a large amount of snow at one time. The material keeps out wind, and provides some protection against the cold. It also provides protection against deer, which are a real problem here in our garden in every season.
The results of last year’s trial were very encouraging. The lettuces that did well included Oak Leaf, Sea of Red, Radichetta, Winter Density, Ruby and Spotted Trout (aka Forellenschluse and Freckles). The tested greens all did well (Arugula, Komatsuna, Yukina Savoy and several varieties of Spinach). The survivors all endured repeated freezing and thawing cycles, and several periods of below freezing temperatures that lasted for days.
cold frames after December, 2010 snow (click on any image to enlarge)
Last year the varieties I planted were limited to what seeds I had on hand for fall and winter planting. This year I planned ahead when ordering seeds, and I have included some varieties I selected specifically for their reported cold hardiness.
And this year I have more cold frames to devote to the testing. Soil preparation included adding about a one inch layer of compost to each bed, plus some slow release organic fertilizer (5-3-3). I tested the pH and it was fine, so no lime was needed. The spinach was direct seeded, all others were transplants that were started inside under lights and then grown on in the greenhouse and outside. The seedlings were all about 3-4 weeks old when planted.
new cold frames added this spring
The spinach was all planted in one cold frame. I have the hybrid variety Space, and the open pollinated heirloom varieties Giant Winter (Gigante Inverno) and Viroflay. Seeding was done on 9/5 and 10/3. Spinach generally survives our winters with a little protection, so I am really interested in seeing which varieties perform best here. I was able to start harvesting some of the leaves in early November.
cold frame with spinach
The second cold frame (#2) is planted all in lettuces: Winter Density, Black Seeded Simpson, Flashy Trout Back, Radichetta, Kweik and Merlot. Flashy Trout Back is a Frank Morton selection of Forellenschluse with more uniform red splotches on the leaves. Kweik is a butter head with cold tolerance suited for tunnels and unheated greenhouse production. The lettuces were all planted in mid October (10/17).
cold frame #2 with lettuces
The third cold frame (#3) is a mix of Asian greens and arugula. I planted Ice Bred and Even’ Star Winter arugula, plus Mei Qing and Ching Chiang pac choi, along with Komatsuna and Yukina Savoy tatsoi. The Komatsuna is an open pollinated variety I got from Nichols Garden Nursery. Ching Chiang is a green stem pac choi supposedly with heat and cold tolerance. I will compare it to my old standby Mei Qinq, which does well in all seasons here. I will likely harvest both of the pac chois when large enough to use and then replant those spots with some Mizuna seedlings I have growing. This cold frame was planted on 10/25.
cold frame #3 with arugula and Asian greens
The fourth cold frame was just planted recently (11/19), and is mostly lettuces with a little tatsoi. The lettuces are Oak Leaf, Spotted Trout, Winter Wunderland, Hyper Red Rumple Waved, De Morges Braun, Rouge D’Hiver, and Ruby. The tatsoi is Even’ Star Tender Tat, which is actually a mustard and tatsoi cross that is supposed to grow more upright than tatsoi and be very winter hardy.
cold frame #4 with young lettuce seedlings
I also have a small cold frame (not homemade) that I planted with some Senposai seedlings. Senposai is a cross of Komatsuna and regular cabbage. I grew it this year in spring and summer and it was very promising. It has large green leaves with a mild cabbage flavor. It will be interesting to see if it can survive the winter here.
cold frame #5 with Senposai
I will report back on these trials in the weeks and months to come, and share the results. My main goal of course is to keep us supplied in greens all winter long, while testing the performance of different varieties. And of course I love to experiment!
I am trying a used yard sale aluminum and polycarbonate “Julianna” model cold frame for the first time (Fall 2011). I am trying “Mache” (or also called Corn Salad), and spinach. I have directly sowed both in mid-November. The spinach has already sprouted.
The purchased cold frame I have is made of polycarbonate and wood. It does a good job, I just wish it were bigger. It would be possible to build a cold frame using polycarbonate panels, I just haven’t gone that route yet.
Sounds like you have an excellent selection of test lettuce going into winter, I look forward to hearing how they perform for you. We also have a section devoted to winter hardy lettuce…fingers are crossed, but if we continue getting lots of snow that always helps with insulation so I have high expectations for the winter garden this season. I’m curious, if you could pick just one or two Asian greens for winter hardiness what would they be?
Lack of snow actually works against us here, as we normally don’t have snow cover most of the winter. Tatsoi (or Yukina Savoy) is super hardy here, while I think Komatsuna gives a higher yield in the same amount of space. The Komatsuna I grew last winter was a hybrid called Summerfest, and despite the name it lasted all winter. Hopefully this o/p variety will do as well.
I’ve yet to make a cold frame. I keep thinking I should some year as it would really help keep the ground unthawed. So far the hoops I use work OK, but some years we get so much snow they don’t hold up well.
I’ve yet to be able to a good crop of winter lettuce. Even the hardiest varieties inevitably turn bitter…except for Winter Density. Did you have a problem with bitterness last winter?
I’ll be interested to see how all your greens do. We routinely keep oakleaf lettuces going, both red and green, because they do will in winter, but they’re also bolt resistant when we get those odd runs of warm weather come mid-winter. We grew Mei Qing choi for the first time this year, and it did amazingly well. I don’t have any going right now, but I do have an overabundance of Mizuna that self sowed. Good grief, I swear Mizuna is borderline invasive. Good thing we can eat it! 😛
Sure would like to have some of those nice fresh greens in the middle of the winter but don’t think they would do well at -20 degrees for numerous days in a row. Also it is a little hard to find a cold frame under 50-100″ of snow. Nice to read that others can do it however.
I don’t have nearly as much lettuce growing in my grow tunnels I would like to have going into the winter. Unfortunately, my largest patch of mixed lettuces were mowed down by slugs as soon as they emerged. So I am left with an older planting of Arctic King butterhead lettuce that (thankfully) has been a strong cold weather performer – living up to it’s reputation. I will be starting some more lettuces indoors in about a week and they will be tucked into the greenhouse containers or under the grow tunnels once they are large enough for transplant.
You have some really nice looking cold frames and the variety of greens you are growing in them is excellent.