Difference between a green house and a cold frame?

alexemmersonuk

I know it sounds silly but I am still confused on the actual difference between a greenhouse and a cold frame. 

Is a greenhouse there to create WARMTH and a cold frame just to create shelter from wind? 

Is that it? 

(Thanks in advance for the clarification) 

fidgetbones

Cold frames do the same job for small plants. Greenhouses you can walk into and grow tall plants.

alexemmersonuk

@fidgetbones ok, so there is no actual difference in what they do? Is it just a matter of size? 
 

BobTheGardener

Yes, purely a matter of scale. In this context, cold = unheated, so an unheated greenhouse is a 'cold greenhouse' and an unheated growing frame is a 'cold frame'.

wild edges

I spent a lot of time confused about cold frames as a kid. My gran had one next to the coal bunker and I thought the word was 'coal frame' because they sounded very similar and it made sense because it was next to the coal bunker. I couldn't work out why other people called them coal frames though when they didn't have coal. It was years before I say the word written down and the penny finally dropped

raisingirl

Cold frames tend to be colder, just because they are smaller so they don't stay as warm at night. You can compensate by using paving slabs or bricks as the floor to the cold frame, which will get warm in the day and stay warmer at night.

SonnieB

Thank you @alexemmersonuk, I always wanted to know the difference, but was too embarrassed to ask. 

Posy

And you can heat greenhouses relatively accurately so that you can grow a much bigger range of plants over a longer period of time. Commercial greenhouses have controlled heat, light and humidity and produce tomatoes in February or strawberries for Christmas. The Eden Project is just a super-greenhouse. A cold frame can be quite large but is never on the scale of a greenhouse so planting is very limited.

Fairygirl

I'd agree with @raisingirl that a cold frame is generally less warm than a big greenhouse, simply because of that size. If you had both in a sunny spot, even on an average winter day with a little warmth of the sun, the greenhouse would be roasting compared to the cold frame. 
It's similar to the way a conservatory would be compared to a room with a standard window, when the sun comes in. The main thing to remember is that those temps can then fluctuate enormously too when that outside heat disappears. A cold frame is easier to maintain a steadier temperature, so it's important to ventilate greenhouses well, even in winter, but obviously depending on what you have in it. 
If you just need a place to overwinter small plants, a cold frame is ideal. 

LeadFarmer

Cold frames are usually used to prepare a young plant for living outdoors, and they make it easy to open the lid so the plant is pretty much 'outside', but the lid can be closed at night when the temperature drops.

Similar could be done in a greenhouse by leaving the door and windows open all day, but I think that would still be warmer than a cold frame with the lid fully open.

Plus in a greenhouse you might have other plants needing constant warmth, which might not like the door being open all day. So cold frames allow you to create multiple areas serving different purposes for different plants.

However I don't have any cold frames myself.

alexemmersonuk

Thank you everyone! I think I got it