Cold frame?

Do-it-yourself projects such as greenhouse or shadehouse builds and related topics.
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ElieEstephane
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Cold frame?

Post by ElieEstephane »

I'm considering building a cold frame with wood and greenhouse plastic sheets until i build the greenhouse. However, winter is pretty rainy here and i would worry about high humidity and condensation inside. Is this something worth worrying about? I was thinking of leaving the bottom open for more air circulation since i don't have to worry about cold except maybe radiation heat loss on a cold night and a clear sky.
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keith
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Re: Cold frame?

Post by keith »

That's what I did built mini cold frames . I think as long as the roof covers the plants in a rain you're OK for Most species in an area that doesn't freeze often and is somewhat dry between rain. I get rain in the Winter none in the Summer and often windy in the Winter here. we just had a big windstorm first of the year. the wind after a rain dries the plants out which is good for cactus. Spring is tough for my cactus because it tends to be cool and foggy and that's when they want water and heat.

This spring I covered benches with plastic to keep heat up. As long as wind is done for the year I can do that. I'm looking for plastic sheets like maybe 2mm thick to permanently screw to the roof of my benches so the wind wont blow plastic off all winter. UV resistant plastic sheets only ones I find at local store are wrong size and super expensive.
esp_imaging
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Re: Cold frame?

Post by esp_imaging »

Sounds like you only need a rain shelter really, you don't need sides to enclose a space to retain heat.

It may not elevate the minimum temperatures, but a rain shelter should raise the average temperatures of the plants. They will be dry so any warmth from the sun will be heating the plants and the soil, not just evaporating moisture.
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DaveW
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Re: Cold frame?

Post by DaveW »

Even in the UK some cacti can be grown in unheated cold frames over winter, mainly to keep the rain off. Some of the Tephrocactus types do better in cold frames over winter than in heated greenhouses, or often cacti from the southern areas of S. America like Patagonia.
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ElieEstephane
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Re: Cold frame?

Post by ElieEstephane »

It seems the consensus humidity is nothing to worry about. I already got the wood and cinder blocks to build the greenhouse so i'm gonna use so of them to build several cold frames.
Keith i think i've seen your setup somewhere and that's basically what i have in mind only wider.
Esp the sides are also to keep the rain out because it's often very windy with rain or it rains at an extreme angle. Also sides will keep the wind from knocking tall cacti over. I will make it in a way that the top opens so they don't cook during the day.
Dave we grow a lot of cacti outisde here in clay soil like cereus peruvianus and forbesii, several opuntias, pachycereus marginatus... and they don't really stop growing in winter, they just grow slower. However, the sun can be out for a few days in a row in winter, it rains a LOT and hail is not a rare occurence so i'd rather keep my cacti dry and avoid the risk.
Thanks everyone for your input.
There are more cacti in heaven and earth, Horatio, than are dreamt of in your philosophy.
One of the few cactus lovers in Lebanon (zone 11a) :mrgreen:
DaveW
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Re: Cold frame?

Post by DaveW »

Yes Elie, I think some in violent hail prone areas also have some sort of roof above their plants to prevent damage to the plants. Though I have heard of some whose roofs have been damaged by freak large hailstones, but it still usually does protect the plants, even if the roof sheets themselves are damaged.

I think Borg mentions in his old cactus book this happening in Malta.

Thank goodness we don't get this in the UK as our glass greenhouses would not stand it.

https://www.youtube.com/watch?v=dtzoZSilZTQ
keith
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Re: Cold frame?

Post by keith »

Just make sure the whole structure doesn't blow over in a wind storm. Secure it to the ground . Will you make your shade house big enough so you can walk inside of it ? take pictures
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ElieEstephane
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Re: Cold frame?

Post by ElieEstephane »

keith wrote: Thu Oct 18, 2018 5:27 pm Just make sure the whole structure doesn't blow over in a wind storm. Secure it to the ground . Will you make your shade house big enough so you can walk inside of it ? take pictures
I'm thinking of raising it to around my waist on cinder blocks (cemented together) and laying the plants on perforated metal sheets. It will look like this but raised to around my waist and with transparent sides so just enough to fit the plants.
Frames1.jpg
Frames1.jpg (106.21 KiB) Viewed 6280 times
However, this is only temporart because i intend to build a greenhouse but i didn't buy polycarbonate sheets yet. I bought wood to build a 6x6m greenhouse (around 20x20 feet) but i'm thinking to only build a 12x12m so i'd have 144 square meters (1550 square feet) to play and walk around in and a small 3x1.5m greenhouse inside to keep my more sensitive plants (adenium, neoraimondia, pilosocereus...)
There are more cacti in heaven and earth, Horatio, than are dreamt of in your philosophy.
One of the few cactus lovers in Lebanon (zone 11a) :mrgreen:
keith
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Re: Cold frame?

Post by keith »

A sketch I made long ago for a small greenhouse on block. Original autocad file is no more.
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keith
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Re: Cold frame?

Post by keith »

Took a few minutes to remember what I was planning . Never built it at least not yet . It was designed around 12 foot polycarbonate panels available at Home Depot a local hardware store . it was a walk in design - probably just buy a pre hung door and screen the sides.
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DaveW
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Re: Cold frame?

Post by DaveW »

I have built 3 or 4 wooden greenhouses for myself and even more conservatories in my time being a carpenter, but in those days in the UK it was for glass since polycarbonate had not yet started to be used in the 1960's and 1970's for greenhouses or conservatories. Polycarbonate needs to have the appropriate suports and fixings in the centre of sheets over a certain width to stand snow load and also the wind suction pulling them off in a gale. Also twin wall polycarbonate sheets have a UV (ultra violet) protective coating on one side which should go on the outside (never the inside) to resist deterioration due to UV rays from the sun.

I found these if of any use?

This first one of for corrugated sheeting.

https://www.softwoods.com.au/blog/polyc ... o-install/

These are for twinwall but I would stick to clear as tinted could affect plants growth. You can always use shade cloth to cut down light, but you cannot increase light from tinted or opaque sheeting if it cuts down too much.

https://www.youtube.com/watch?v=p9ktZ3wIlxg

https://www.youtube.com/watch?v=BWTQhzA2uHY

https://www.youtube.com/watch?v=2Oq7-D8DqF8

These days in the UK unless cedarwood is used we prefer aluminium greenhouses as they don't rot in our wet climate. Also don't rip the plastic protective cover off the twin wall polycarbonate rapidly, peel it reasonably slowly as it can act the same as a Van de Graaff static generator and give you a shock from static electricity. My mate did that once and finished on his backside on the grass from a static shock. :lol:
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