Are the seedlings still in a container, or were they transplanted under the cold frame?

The seedlings are in the container (a 10 gallon round bucket) which is where I intend them to stay, thinning out the weaker plants as they leaf out. Hopefully, I'll end up with one strong, productive plant in the bucket, which is wide enough to hold a cage support, and light enough to move indoors if fruit ripens late season, or the plant outgrows the frame.

I did move the bucket inside the cold frame (it's a vinyl tent top, actually) about 3 hours ago. The inside temperature is not that much warmer than ambient now, though it was 10-12 degrees warmer inside when the sun was on it. Humid too-I'll be keeping an eye on that.

All I know to do at this point is be patient, keep the plants warm and a little thirsty. They've only got the initial pair of leaf slivers, which is as far as I got when I tried setting them out in peat trays last year. Those withered and died without forming secondary leaves. Perhaps there was too much humidity, or not enough food to sustain them. This year's crop was started in potting soil and seems a lot hardier--leaves are a darker green and tougher looking than last year's. Is there something more I should be doing, like fertilizing?

Well, 10 gallons should be plenty big to grow one tomato plant, if the drainage is decent.

The trick with late-spring cold frames or coverings of any kind is to realize that 45 minutes of full sun will turn it into an oven. Best left open all day, closed at night. Note that a car parked outdoors is still getting toasty now even on overcast days.

More common terms are proto-leaves and true leaves.

The plants need to get bigger before adding any fertilizer.

Just spotted some true leaves on a couple of the seedlings. I'm thrilled!

Caught what you said about sun just in time yesterday--tomato house temp had gotten up to 85.5 F without my realizing it. Wouldn't a radio thermometer programmed to text message temperature warnings be an excellent thing.

That's a good temperature for tomatoes, but it may have been 20 minutes away from 100ð with continued sun.

Once tomatoes bloom, hot temperatures can reduce fruit set.
Best to keep below 90ð.

I'm taking your advice about keeping the house open during the 70-degree F no rain days we're going to be having for the next few. And I've started carefully thinning the seedlings a bit at a time.

Thought you might be interested in these remote temperature sensor relays that my hubby found on the Internet. They look promising, if a little more than I would spend. I'll be on the lookout for a generic equivalent.

http://www.treehugger.com/gadgets/monitor-your-world-these-tiny-wireless-sensors.html

Those are nice gadgets. But of course one has to be nearby to open the cover and rescue the plant (large elaborate greenhouses automatically open vents and turn on fans). A week or two of experience with your existing thermometer could make you as smart as the sensor and app.

It is far more important to keep the tomato plants warm at night rather than warm or hot during the day. Closing the house just after sun leaves the area for the day will retain the most warmth.

Purplethumbedles, I've been doing a bit of reading on the tomato forum and found myself wondering how your German greens were coming along...? Did you get some strong plants?

Thank you for asking. I've been meaning to post a picture.

The plants are 8-9" high now, and I've thinned them down to four sturdy ones. They are visibly larger each day and thriving. I'm going to be transplanting the three extra's to other containers in about 2 more weeks, once night time temperatures are staying above 55 F. Maybe they'll even make it. The centermost plant should continue to do well, but its good to have a spare. (The heirloom and the speirloom?)

Lol- how we become veggie pack rats ;) They are looking good. Keep us posted...

The first blossom cluster has opened on the German Green. Come on fruit! This is exciting.

Exciting, but this may become a house plant if you are to realize ripe tomatoes from it at this late bloom date.

Anything under 50 degrees can stop the process.

Yup. That's why it's in a container. Figure to move it inside near the gas water heater when nighttime temperatures dip below 55-degrees F again.

Promising! Looks like you've got this. Would some kind of green house or cover outside keep it warm enough as well as develop better tasting tomatoes than bringing them inside would? Rooting for you!

My goal is to have viable seeds to sow in the ground next year. So if there's baby fruit by the time this container plant has to be brought indoors, then the warmth inside may see it through to a mature seed tomato. I do have that plastic cover, but it still gets cold under there.
There's no question that a tomato grown in the ground through a hot season has alot more flavor and sweetness. I've got a few of those and have been picking when the fruit is still just a tiny bit green and will finish ripening on the sunny windowsill. OMG they're good. Saving the one Mr. Stripey I've got so far, and am impatient for more of the Brandywine's (pink-red toms toward top of photo) to do their thing. Yes: I've turned into a real TomatHo and there's no going back.

The chosen bush has produced 3 small fruits. This one ripened indoors while I wasn't paying attention; the other two are still hard and green.

I remember the original fruits being dark green with red streaks. Did a cuckoo get in the nest here, did my bringing the plants inside effect the color, or do the roots need contact with the ground in order for the plant to thrive?

Harvesting the seeds anyway, and will see what I get next year!