I have been doing it for many years.

Great way to get a couple od months' growint time.

dcarch

Is it possible to start tomatoes in a cold frame?

Sure can, if you can get your soil temp up and keep it up.

If I would start the tomatoes indoors and once they germinate, take them out to a cold frame - would they survive and continue to grow?

That's how its done, but you have to keep it up over, say, 45ºF at night in spring.

I actually have one of those popup flower house green houses. Would that work as a cold frame?

If you are describing one of those 3-shelf things with about 10mil plastic and a zipper, you won't be able to keep it warm enough at night for toms, esp starting them. Most coldframes are wood sides and glass tops, preferably two layers of glass for what you want, and some way to vent in the day, either going out there and physically opening the top or having a vent opener do it. Then remembering to close it before sundown to keep in the heat.

Dan

Thanks for the information - I appreciate it. dan_staley, you said that you need to keep the temerature at least 45ºF. Is that possible in a cold frame if it is below freezing outside? It is not too uncommon to have below freezing well into March here at times.

Thanks again,
Mike

Thanks for that great idea kudzu9. All of this information has been very helpful. It has given me what I need to know to think about.

Thanks again,
Mike

I'm at 5700 ft and my coldframe is ~44ºF right now, outside is ~28ºF, yesterday not full sun. Today will be full sun and this time tomorrow it will be warmer inside. But that is because the sun is so intense at this altitude.

Nonetheless, there are coldframes and hotboxes, where the hotbox has added heat, usu by electricity. There are soil heating cables available thru the seed catalogues, or the germination mats described above, or a string of old-style Christmas lights for added heat. In March there most people use their coldframes to harden off their crops, taking them out there in the morning and bringing them back in for the night, usu for a week-10 days. If your temps are going to be below freezing a coldframe will keep the frost off and above freezing, but not much more, as kudzu said. One other thing: control leaks. Even several small holes mean heat loss, esp in wind.

Dan

Thanks for the additional information dan_staley.