While the temperatures you post are not good for rapid germination of seeds, they should support moderate to slow growth of tomato plants. I would suggest you make sure the plants are well established seedlings before committing them to the "indoors". Keep the newly germinated seedlings warm until they have at least the firt set of real leaves - preferably the second set.

Ted

hi grrrr.egg no probs I go down below freezing. The first tomato last year was Marmande which set while others had their flowers falling off. This year I'm trying more cold climate varieties including pathenocarpic tomatoes that set at lower temps. many of these are available in Oz. Cheers Max

Greetings from very far away! The temperatures you quoted are outside temps, right? What matters is the temperature inside the hothouse. For myself, on a sunny February day in Illinois, which is our very early spring, it can be 7 degrees Celsius outside and yet still be 35 degrees inside. Solar gain should make it nice and warm inside, and you should have tomatoes as long as things don't freeze on a cold night. Good luck with everything.