Thanks all for your thoughts & stories. I know that most greens should survive, but I'm glad to hear others have tried seeding in winter as well. The fold frame is 36 right now, so i think I'm going to create a heat-sink with some bricks and add some weather stripping under the windows to increase the temp. In a few weeks I'll direct seed some beats and let you know how it goes. For now, I'll start some seeds inside and transplant them in the cold frame and hoop. I'll be sure to take photos soon! I'm a former zone 5 resident, and I know I couldn't germinate anything this time of year up there, but the snow would mean lots of stuff survived that otherwise wouldn't.

I dont have access to scientific data but have planted tomatoes in the past when night lows had dropped to low 40s and hi 30s. And my plants did fine that season. More than air teperatures, soil temperatures are important. When soil temperature measure over 60, during the day, it is not going to cool down considerably (at roots level at night) even when air temperature goes down to 30s.This is especially true, if the plant is mulched well. But as mentioned above, surviving is one thing and growing another. That is why , in my experience, late planted tomatoes catch up with the early one, very fast in warmer soil and air temperature.

If that were the case I should have stopped growing tomatoes all together. Why do you assume it is an either/or situation? You keep insisting that for you the choice is either plant them out so early exposed to much colder than recommended weather or don't plant at all. That simply isn't true. And then you go even further by repeatedly pontificating about it and recommending this approach to others when they ask. All because you are trying it with a few tomato plants in your location it is ok for them to do it too? If it works for you fine - good luck. But why are you so insistent that others do it too? Why do you insist on restating your claims about this over and over in so many threads? It is only marginally interesting, it applies only to you, and it is misleading to others. So why? Is it just to prove that all the research and all the experiences of so many others are wrong and only you truly understand how tomato plants tolerate cold weather? Now that would be arrogance. Nothing in any research done or in any common practice says you cannot grow tomatoes when the outside ambient air temps are below 50 You simply (a) delay your planting when possible or (b) when it isn't you adjust the environment by providing cover so that the air around the plants is at least that warm. There is a whole range of ways to accomplish it without any risk to the plants by simply growing them under some sort of cover. Lots of people do it. So could you. If you choose not to, that is your choice. But that choice in no way makes your methods correct or something to be advocated when it directly contradicts so much evidence. You insisted on links. You got them. Many many more are available. So now you dispute their validity simply because they disagree with your claims. Then I and others can dispute your claims simply because there is so much scientific and anecdotal evidence against it. The OP got their answer many emails/posts ago and so has anyone else who read this thread. There is no way you will be able to prove your claims about tomato cold tolerance are right and everyone else is wrong so it is way past time for you to let this issue go and move on. Dave This post was edited by digdirt on Sat, May 24, 14 at 18:49

I'm not familiar with midwest weather Randy but in North Tx I must plant at the very earliest date after frost,plant two weeks early and cover when frost threatens or use cold frames to give plants a head start. The time between last frost and 90 deg F where blossoms no longer set isn't long enough for tomatoes varietes over 70 days. Most people plant two weeks before last frost and cover as needed. The problem with that is if you are delayed in removing covers plants can be shocked or killed from overheating. My answer is in my cold frames. My frames are much taller than conventional. I am both curious and frugal so I repurpous,recycle and experiment at every opertunity. I will explain one frame that you are familiar with so that you can see how I build a frame from scratch. i rescued a supermarket reach in dairy case which is about perfect. I cut a 6" vent near bottom and installed a 3" flexiable hose at top. Hose runs down 18"to connect to a box containing fan from dairy case. The descending hose prevents heat lose by natural convection (warm air rises,cold air drops.) The thermostat has one set of contacts that make on temperature rise above an adjustible 32F to 55F and break as temperature drops which in turn control cooling compressor. There is a secound set of contacts which make and break inverse to first set. When unnessary components were stripped,I retained defrost heaters and connected them to the secound set of contacts which make on temp fall turning heaters on then break when temp reaches 45-50F. Another salvaged t-stat was mounted high in case, internally altered to perform in the 80F range and connected to fan. I save and raid gas station island trash for black oil,trans fluid and anti-freeze jugs. Jugs are filled with weak mix of water/anti-freeze then placed inside case where solar heat is stored then released during night to miniumize energy used by defrost heaters. A chime is connected parallel with heaters and a buzzer with fan to allow me to dial them in. Plants sit near top in colder weather then decend to lower shelves as they grow and weather milds. When plants are removed from flats they go into 1 gallon pots. Cumulativly, years tinkering has shown as cu ft space inside frame increases, maintaining temperature becomes increasingly easier. Gallon pots ease moisture and nutrient maintainance, reduce transplant shock and alow plants to hit the ground running. I hope this was relivant to your question.