Posted: 24/03/2015 at 09:25
Tomatoes are incredibly tough once they get going. The key to germination is warmth, preferably from beneath. An ideal temp for germination is in the mid-20s. They will germinate at lower temps but will take longer. Once germinated, temp is (relatively) less important, with light the key. As much as possible, preferably natural sunlight.
Bubble wrap is an excellent idea. I use it. If you have the seedlings in some sort of crate or tray, wrap the whole thing securely in bubble wrap. The bubble wrap will retain any warmth generated during the day, you shouldn't need fleece overnight unless it gets seriously cold.