Mine have been out for about a week and are already nearly two feet tall, but I don't plant them in the ground. I just have two in big pots on my deck, but it's south facing and bakes all day long so they love it there.

I have been experimenting this year by putting a few cold hardy tomato plants out very early in a microclimate area. Results poor, plants just sitting there with no or very little growth.

I have re-learned very quickly that getting any tomato plants out early is simply pointless and I am finished experimenting. I will go back to my normal strategy of planting out in June. Soil temperature will dictate which week in June, but planting time for me usually averages around the second or third week.

In the past I have also tried to cheat ma nature by using ground plastic or wall o' waters and found both methods to be utter failures as well. A person simply can not warm up all that ground soil mass artificially or "trick" tomatoes into growing. Patience and warm temperatures - that is really all there is to picking the time for successful transplanting. A soil thermometer would be a helpful investment as well...

I wish things could be different. I love tomatoes but have to wait so long into summer to get the maincrop types. Rather frustrating but can't do anything about it. Makes a person appreciate and enjoy them that much more I guess.

Container tomatoes are a different subject, although they are still affected by cool soil temps in the pots. I have already been harvesting container cherry tomatoes, but they do not compare in any way to a vine-ripened beefsteak. And you have to make really tiny bite-size BLT sandwiches. ;)

Good Luck!
-Tom

Soilent... do you think that there might still be some root growth during the cool temps, even though there is no top growth?

"...do you think that there might still be some root growth during the cool temps, even though there is no top growth?" Possibly, but I do not know the answer to that personally. I know that all of a sudden the plant growth will take off so to me that says root growth is occurring prior. Guess I should dig up one of my early plants now to inspect. If I decide to do this I will take pictures and post. Should be easy to see because I planted deep to bury the stems, and those buried stems should show signs of root development by now.

The thing is, there are scientifically established optimal soil temperatures for commercial and garden tomato growing and my soil is still not there yet. I wonder if cold soil early will negatively impact production quantity or quality later on, even if it does not visibly cripple the transplants. My gut feeling is that it does but have no proof to back up that opinion.

That brings up another issue I have: Are cold tolerant tomato varieties developed for earlier plant-out or for more hardiness against late season cold weather, or perhaps both? Questions more relevant to the GW tomato forum or a separate MN Gardening thread than for here - I apologize to the OP for highjacking.

I can't speak for the OP, but I think all of your above comments are very relevant to the original question: "When to plant out" It does seem a lot more complicated that just worrying about a late frost killing the plants.

I'm 25 miles north of Brainerd, and I planted mine last Sunday. I have a large collection of 5 gallon pails that I can use inverted to cover the plants. I don't put cages on them until June. It looks like I may need to use the pails Thursday night.

My gut feeling is that this may be a cool, wet, short season.

This year, I am using a heavy (6 mil) black plastic over the tomato area. Plants are set in the 9 inch diameter holes that I cut in the plastic. The plants are all 4 ft apart in all directions to get more air circulation and sun coverage. I normally go with 3 feet apart in rows 4 ft apart. Blight has been a problem for me on cool, wet years.

Soilent, now I'm wondering if planting out early also increase ones risk of having more problems with blight later on? Induced by plant stress and wet, cold soil? This is all very complicated..... My head hurts.

If in fact, there isn't any root growth going on with an early plant out in cool weather, waiting until June does make a lot of sense.

I am relatively new to growing tomatoes. All the plants that I plant in the garden are grown by seeds. Tomatoes have been one that I seem to start too late. This year I was determined to have a successful experience. Started early, transplanted to larger container, removed from artificial lighting, fish emission as fertilizer, and hardened off seedlings. Worried a bit about leggy seedlings in the beginning, tried to figure out optimal height of seedling before transplant to garden and now it is nearing time to just make the move to the garden. I figure wisdom is gained with each gardening experience both successes and disappointments. I will be more than happy if I can achieve even (1) edible tomato through this process. Obviously more would be fantastic but it is all part of the learning process.

Glad to see the MN forum has had some more active postings -- Seems to be a relatively quiet forum.