Cold Frame

wannabegardener
Herbaceous Perennial
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wannabegardener
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Joined: 10:30 PM - May 23, 2003

8:15 PM - Aug 19, 2003 #1

Hm. Okay .
How much difference is there - approx. - between outside air and that of a cold frame ? Generally speaking .
Like for example , if it is 0 Celsius , 32 F , Cold frame receives 4 -5 hours sun maximum - majority in morning .
I'm trying to figure it out in my head instead of with my hands - Theresa
The only reason people get lost in thought is because it's unfamiliar territory.
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Nehlad
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Nehlad
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Joined: 6:00 AM - Jun 30, 2003

8:46 PM - Aug 19, 2003 #2

Hi wanna, lets put it this way, if a thermometer is placed in a coldframe which is then sealed but left in open sunlight it will blow the mercury out of the the thing. It happened to me by accident. There is no answer that I know of as there are too many variables. nehlad.
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wannabegardener
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10:03 PM - Aug 19, 2003 #3

Nehlad , I guess what I was wanting to know if it is possible to have the temperature in a cold frame to be 20 degrees - 30 degrees F. warmer than outside temps.
Now where my question stems from is often the temperature here in March is still very much in the 30's F. Is it possible for me to jump start my growing season by starting in January and February in cells then transplant to a bigger pot and place in cold frame . Would the temperature in the cold frame be able to maintain a minimum 55 F ?
Would 4-5 hours of sunlight be sufficient to warm up the cold frame 20 degrees above the outside temps ?Theresa
The only reason people get lost in thought is because it's unfamiliar territory.
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scotia10
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Joined: 2:12 AM - Jun 24, 2003

12:16 PM - Aug 20, 2003 #4

Lots of questions here Theresa,
Now there are cold frames and there are cold frames.
There are single glazed,double glazed, glass sides,solid sides, heated, not heated, or any permutation of these.
I think the answer is in the name...COLDframe.
Usually these are used as a transition area from the heat of the greenhouse to the cold of the outdoors. As such they are basically protected areas from the worst of the elements.
>> is possible to have the temperature in a cold frame to be 20 degrees - 30 degrees F. warmer than outside temps.
>>Would the temperature in the cold frame be able to maintain a minimum 55 F ?
What is the point? if you have a heated greenhouse, or for those without, a warm windowsill or airing cupboard.
Most plants only require heat to germinate, say 18C (65F) there after you only require temperatures of around 7-8C(40-45F) i.e. just above freezing, hence the cold frame.
Basically what you are saying here is; can you turn your coldframe into a greenhouse. Yes! you can, with a heating system, but then you have lost your coldframe.
>>Would 4-5 hours of sunlight be sufficient to warm up the cold frame 20 degrees above the outside temps ?
Yes! for the four or five hours, but then the temperatures will plummet as the sun goes down.
Heres a few tips for getting the best out of your coldframe;
1) Keep your compost your plant are in as dry as possible without going bone dry.
This will increase the temperature at root level by about 2-3C (5-6F)
( its the water content that get cold, not the porous compost)
2) Depending upon the size of your frame, light a candle/s place on a saucer (nightlights are ideal) and surround it with a tin can with the top and bottom removed.
This will give off enough heat to keep your cold frame just above freezing point overnight.
I have known people use electric light bulbs for the same purpose. But water & electricity don't go hand in hand, so beware if you go down this road.
3) During the day, when conditions become slightly warmer you will find lots of condensation dripping from your cold frame lids.
It is better to lift the lids slightly to keep the air on the move.
As another precauation to keep moisture to a minimum cover your plants with an agro fleece, this will soak up the moisture.
Depending upon your method of heating (don't want to set it on fire) you could leave the fleece over your plants at night and this will give a micro climate a few degrees warmer.
4) You could always place a soil cable in your coldframe and this will transmit heat to where you want it, the root system.
You may recall a week ot two ago I pointed out to the forum on how I heat my greenhouse, and basically my 'high heat'is in a propagator roughly 26"x14".
My 'intermediate heat' is a hot bed.
And my basic air temperature is controlled with a fan heater, which I must say has rarely come on this last couple of years.
To sum up; If you can get? firstly; a soil cable, (ideally with a thermostat) secondly; a thermostatic propagator, you will find you will cover most of your needs.
Hope that covers all your questions.Scotia
http://www.thegardenersalmanac.co.uk
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wannabegardener
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1:52 PM - Aug 20, 2003 #5

I wasn't going to bug you again . But yes , that answers it. It means I am stuck for the time being with biennial Hollyhocks .
Biennial everything .
The best I can do for the time being is get an early start on plants by a month - 2 tops .
The cold frame will serve it's purpose for tender perennials . And it will allow me to have a safe place for tomatoes and such from frost damage .
Peter had shown one before , Scotia , that consisted of landscape timbers placed on top of concrete blocks with a glass raiseable top .I have all but the glass door top and thermometer so that is the route I'll be going .
Greenhouse is a dream but not for a few more years . Too much on my plate now as it is.
Thanks for the info .Theresa
The only reason people get lost in thought is because it's unfamiliar territory.
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