Advice on Building Alpine House/Greenhouse

[Jan Jeddeloh]

After years of dealing with a too shady, too steep garden we're moving!  Our new place will have room for a sunny rock garden and a sunny greenhouse/alpine house.  I'm looking at one of BC Greenhouses (bcgreenhouses.com) Cottage style in the 8'7 1/2"x 12' 8 1/2" x 8' 11' 3/16" size.  So more or less 2 1/2 meter wide by 4 meter long.

The plan is to do a plunge bed along one side with benching on the other side so I can use it both as an alpine house and a cool greenhouse.  Supplemental heat would be turned on only when the temperature is expected to drop below freezing and only enough to keep it barely above freezing.  I do overwinter some non-hardy plants.  I would also use it for seed starting in spring.

I have some questions for all you experienced alpine house owners.

I can get vents which open about 45 degrees run all along both sides or I can get louvered windows.  The hitch is that I couldn't afford many louvered windows because they run $235 each versus $99 for the 45 degree vents.  Can I get buy with just vents?  I live in Portland, Oregon which is extremely humid in winter.  Think never ending rain and 7-8 C all winter long.  I plan to install a fan primarily for summer ventillation but I could probably run it in winter too.  When it gets really cold I'd close the vents.  Will I get enough air flow with just the vents? 

I can have either glass or twin wall polycarbonate for glazing.  I could also have a polycarbonate roof and glass walls.  Any advice on which to choose?  This greenhouse is going to be situated in full, blazing son.  I'm not sure there will be any shading.  The property was carefully chosen for SUN. 
I've been growing trilliums, erythroniums, cyclamen  and ferns for years and am itching to grow some sun lovers. 

Any and all advice will be greatly appreciated.  I envy all you Scots and English who can buy such things as ready made plunge beds.  I'm not sure much husband quite understand yet that he's not only going to be putting together the greenhouse he's also going to be building me plunge bed (topic for a separate post).

Thank for your help.
Jan Jeddeloh in Portland, Oregon

[Maggi Young]

Jan - first of all -  I wish you great happiness in your new house and garden!
I expect there will be much advice coming soon for your questions - but perhaps  these links to older threads may  prove interesting ....
http://www.srgc.net/forum/index.php?topic=5.0
http://www.srgc.net/forum/index.php?topic=2994.0
http://www.srgc.net/forum/index.php?topic=3046.0
http://www.srgc.net/forum/index.php?topic=5945.0

http://www.srgc.net/forum/index.php?topic=3393.0
http://www.srgc.net/forum/index.php?topic=6015.0
http://www.srgc.net/forum/index.php?topic=8605.0

http://www.srgc.net/forum/index.php?topic=8758.msg237910#msg237910 - describing some of the best  plunge staging available in the UK

[Jan Jeddeloh]

Thanks Maggie.  Our weather has been lousy today-pouring rain-so I spent a lovely afternoon with a cat on my lap looking at all your links.  A lot of these houses are truly impressive, even the ones that aren't "fancy" grow great plants.  It looks like a lot of them don't have vents all along both sides, just some additional venting on the sides.  At $99 a pop it adds put if you need five or six per side. 

I noticed someone mentioned greenhouses run east-west and alpine houses run north-south?  Is this necessarily always true?  The sun, such as it is, is shining up from the south in the middle of winter.  I've been so starved for winter sun my inclination is All The Sun.

Thanks again,
Jan

[David Nicholson]

Jan, I'm really surprised at the cost of louvre vents at your side of the pond. Here you can buy a kit for the frames for under £30 and the glass might cost you the same(ish)

http://www.amazon.co.uk/Two-Wests-Elliott-Greenhouse-Louvre/dp/B004TJHHS6

[Graeme]

Jan, I'm really surprised at the cost of louvre vents at your side of the pond. Here you can buy a kit for the frames for under £30 and the glass might cost you the same(ish)

http://www.amazon.co.uk/Two-Wests-Elliott-Greenhouse-Louvre/dp/B004TJHHS6

not that keen on them - they have no top or bottom rail - and no glass..............
Last time I had some like that I spent ages building top and bottom rails - I just wish I had spent £50 and had full four sided units with glass
http://www.amazon.co.uk/Elite-Blade-Louvre-Vent-Non-Coated/dp/B00CI6FZSG/ref=sr_1_17?s=outdoors&ie=UTF8&qid=1433438403&sr=1-17&keywords=Greenhouse+Louvre

[Jan Jeddeloh]

Hey, I don't know why the louvered vents cost so dang much either.  I think these are designed to fit exactly into BC Greenhouses product and they include glass.  They're also painted to match the framing which is likely to be green in my case.  I want my greenhouse to be not only practical but pretty since it's going to be really obvious in my backyard.  My real fantasy greenhouse has an entry vestibule and brick side walls but that's not going to happen.  Too expensive. My budget's about $10,000 as it is.   I'm going with this greenhouse company because I have one of their greenhouses at this place and it's held up great over the 18 years I've had it. 

So back to my question of ventilation.  Can I get enough ventilation thru side vents instead of louvers?  I can put in two side vents for the cost of every louver.  I'm also planning to put in a fan system.  I have one in my existing greenhouse, which faces west, and it will keep the outside temperatures equivalent to outside air.  I deliberately oversized the fan to move the air. 

Luckily I have a handy husband.  I don't think he quite knows what he's getting into however.

Jan

[Maggi Young]

I would think you'd be okay with the side vents and fans, Jan. Would  it be possible for you to take out some panes of glass in warm or humid weather to replace them with weldmesh, as many of us do in the UK?  Many of us take a whole row of glass out in that way over summer.  Will ask Ian  to look for a photo to illustrate that - but Andy Murray is playing tennis in France at the moment and the match is live on TV - this make take a while!