I am planning on building a cold frame that will be either 6 feet by 2 feet
or 4 feet by 2 feet. I would also like to install a solar activated vent
opener on the box. Most commercial units of this size seem to have 2 - 3
lids (vents). Is it possible to have only one vent in the middle that is
about 2 foot by 2 foot in size....is this enough ventilation. My main goal
is to get away with only buying one vent opener.

To reply directly, please remove "_nospam" from my email address.

--Shannon Hughes

In article k.net,
Shannon Hughes wrote:
I am planning on building a cold frame that will be either 6 feet by 2 feet
or 4 feet by 2 feet. I would also like to install a solar activated vent
opener on the box. Most commercial units of this size seem to have 2 - 3
lids (vents). Is it possible to have only one vent in the middle that is
about 2 foot by 2 foot in size....is this enough ventilation. My main goal
is to get away with only buying one vent opener.

My 4x4 cold frame has a single vent opener, which raises the entire
lid. The key is the weight that the opener has to lift -- which should
be specified for the opener.

An amazingly high temperature can develop in a cold frame on a sunny day,
so I'd be wary of trying to use a small vent on a large cold frame. I
once baked (killed) some sweet peppers when a vent was improperly re-attached.

-frank
--

Frank Miles wrote:

In article k.net,
Shannon Hughes wrote:
I am planning on building a cold frame that will be either 6 feet by 2 feet
or 4 feet by 2 feet. I would also like to install a solar activated vent
opener on the box. Most commercial units of this size seem to have 2 - 3
lids (vents). Is it possible to have only one vent in the middle that is
about 2 foot by 2 foot in size....is this enough ventilation. My main goal
is to get away with only buying one vent opener.

My 4x4 cold frame has a single vent opener, which raises the entire
lid. The key is the weight that the opener has to lift -- which should
be specified for the opener.

An amazingly high temperature can develop in a cold frame on a sunny day,
so I'd be wary of trying to use a small vent on a large cold frame. I
once baked (killed) some sweet peppers when a vent was improperly re-attached...



a 2 x 2 foot vent should be ok for a 2 x 6 foot cold frame if it opens
wide enough. If the vent is heavy you could try adding a counterweight
on it to make it easier to open.

The vents are not solar activated, but thermally activated. They don't
depend on the sun (except that the sun heats the air in the frame). They
will open on a warm night.

Not Familiar with a thermally activated vent. Who sell them?

Thanks Bobby

I've built a cold frame where the entire glazing opens when the inside temp
rises. The key is not to use glass over wood frames but Lexan glazing sheets
you can find at any big home harware outfit. Amazingly lightweight, all
clear. Minimal frame needed.
The openers are British and can be found at LeeValley.com in the gardening
section. if the link is wrong do a search for LeeValley Tools in Canada. I'm
sure the gizmo is available in the US
They open progressively so the "lid" will not be "fully opened" or "fully
closed". They react to temp so more temp= more travel. Max travel is 14" or
thereabouts. Load is something like 15 pounds. Their "sensitivity" is
adjustable so you can keep more or less heat in.
Would gladly supply more info if required. Might be able to sketch then scan
something for anyone interested.
No pics 'cause up here a strange white powderee stuff covers everything for
another couple of months!

Mitch from Montreal
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"Bobbyc28" wrote in message
...
Not Familiar with a thermally activated vent. Who sell them?

Thanks Bobby