eric, your house and aspect reminds me of a demonstration house built by bill mollison and his students at a university in australia as relayed to our class, and it was the perfect situation of a home and attached greenhouse, needed no added heating and cooling (temperate climate)
so lucky to have the slab and the sun!

go for it!

I use the house as a greenhouse.  Many citrus do pretty well without that much light.  They get east and a bit of south and north and seem content with that. 

I love it when the grapefruit goes into riotous, pungent bloom at Christmas!  It so beats the whole pine in the house with fragile ornaments thing. 

I think of it as very permie that my 30-year old tree does the decorations for me.  The lime is also nearly 30 and happily yields limes if I fertilize enough and run around pollinating.  I'm a bee-like person anyway, and I love citrus fragrance. 

My mandarins have been edible skin and all. 

Worms frequently ride into the house.  I took one of the trees to table at a trade show for the permaculture guild, and when I got home, a worm jumped out and made a run for it.  There wasn't anywhere for he/she to go, so I returned her/him to the pot. 

Coffee grounds as top dressing attracts worms in.  Some years sow bugs have stowed away as well.  They munch rather noisily on downed leaves, but the aeration of their escape to the depths is probably work that I would need to do if they did not.

A bonus is that the plants like carbon dioxide, and they exude oxygen for wood stove and house mammals.

JadeQueen wrote:

Worms frequently ride into the house.  I took one of the trees to table at a trade show for the permaculture guild, and when I got home, a worm jumped out and made a run for it.  There wasn't anywhere for he/she to go, so I returned her/him to the pot. 

it is really quite easy to work out if the worm was a he or a she
she worms love to shop!
and that one was a little slow to the escalator!


your house sounds intriguing as a citrus greenhouse, perhaps post some pertinent pics

Any opinions on mike oehler's greenhouse book? I've read through a lot of it and as far as greenhouses go, it seems like a pretty good option in terms of a low carbon footprint. Especially if you could source some of the materials second hand. We're looking at building one using some reclaimed wood from an old boat storage, and gigantic windows from a government building.

We have had a greenhouse attached to our house going on 4 years now.  Actually it used to be a 6,000 square foot dairy barn that we turned into our living quarters and a greenhouse.  Since it is an old barn it has a concrete floor which supplies enough mass to keep it warm enough.  With -10F the coldest we have ever been is 24 under a second cover.  It's taken us 4 years to learn what grows and what doesn't.  From the end of October until the end of February everything stays dormant.  We really need 10 hours of daylight for growth.  Bugs are a huge problem every year no matter what we do.  We look at heat in the summer as a benefit, since we dry and cure alot of produce in there.  We have had stand alone poly greenhouses, and unless you're farming for a living you are probably better off getting perennials.  Between worrying about the wind, snow, and the rot that always comes with a dirt floor, it's alot of problems to deal with. We're zone 5, and by 3/15 sorrel ramps burdock and other stuff is coming up.  We used to post on alot of farm blogs when we were just getting started and hands down the one thing the most of the farmers wished they had done earlier rather than sooner was build a greenhouse.  They/we are farming for a living, having produce early or through the winter increases your income substantially.  If I was just looking for greens for the two of us, I would probably just grow micros.  All you need is one fluorescent light and you can get around 2 pounds of greens a week.
We have some pictures of our set up on our blog, along with the bermed house we are trying to finish up.
My 2 cents.
Ed
http://luckydogfarm.wordpress.com/
PS I love this site. Which I had found it a long time ago. BTW the Holzer links seems to be down. 

Jade you gotta let us see pictures of these old citrus trees in the greenhouse!

  You must have auto vents for the summer, put foil bubble insulation on north side to reflect light back, put door and small woodstove on north side as well! And yes no trees on south side.
  Study various plants that are way better for winter- root plants etc..
  If you can build a small riser wall with earth berming around it this can be a HUGE amount of thermal mass, and any sort of fish tank or 55gal barrels to raise catfish this can also store thermal mass and have fish to eat with your salad!
  Look up Glacial rock or pulverized rock from quarries this stuff is great! most soil in US is depleated~
  New CO2 generator and heaters for greenhouses that run on 100% Veg Oil, and cool Geo Dome greenhouses for max snowload  www.lodge-tech.net 

Pros:
I can isolate accidental cross pollination.
Ability to initiate earlier starts for the garden
Not only extend my local growing season but grow non-natives from warmer regions.

Pros of greenhouses:
   Extended growing season
   Make great airlocks to your home
   *sometimes* can be used to heat your home
   *if* build with reclaimed materials, earth friendly
   Growing locally reduces fuel needed to truck produce long distances
   A good place for your soul surrounded by plants and growing things
   Can be used for more than just plants: raise fish using aquaponics, rabbits could provide manure, keep chicks warm, treat gray water, etc.
   Mike Oehler says if you do it right, they can be super in his book THE EARTH-SHELTERED SOLAR GREENHOUSE BOOK

Cons of greenhouses:
   Cost
   Store bought requires a lot of resources
   Type of glazing can reduce different spectrum of light
   Cut off from natural systems such as rain, insects for pollination, etc. You must do nature's job of watering, pollinating, etc.  Not working with nature but against it
   Hard to regulate the temp (may need to heat it in the winter and easily overheats in the summer without vents & fans)  Even temp swings between day and night.
   Must be thoughtfully placed to gain the most amount of winter sun (site often not taken into careful consideration)
   High humidity inside can cause mold
   Building materials degrade quickly due to intense sun and humidity
   Sunlight can be blinding in winter
   Indirect sunlight (using solid roofs, overhangs, shade trees in attempt not to overheat) in the summer means plants leggy/don't thrive
   Severe weather (heavy snow, floods, hail) can easily destroy a greenhouse

Questions I still have:
   Did I miss any of your ideas?
   Has anyone ever put their beehive in a greenhouse for the winter? Is this a bad idea for some reason I haven't thought of yet?
   I am so confused about whether to insulate the floor. Some places I've read say to dig down to below the frost line. The heat from the Earth will keep the greenhouse a constant temp. When you do this, you want to insulate the walls down to the frost line so the Earthen walls do not absorb the heat. Other places I've read says that you need to insulate the floor even below the frost line. Which is it? And Why?
  What does Mike Oehler specifically say about the amount of glazing in greenhouses?

I'm curious about bees overwintered in a greenhouse too.

Robert, check out this website I found:  http://www.beesource.com/forums/archive/index.php/t-228717.html

One thing about greenhouses for winter growing or spring starts in northern climates -- get REVERSED low-e panes...makes it hot in the summer, so you have to ventilate, but it traps a lot of heat in the winter -- but only if it gets good sun, lie the man said...

Costco Canada has a sale on greenhouses at the moment and I'm thinking about buying.

Here's the link: http://www.costco.ca/Browse/Product.aspx?Prodid=10344941&search=os0317&x=mode+matchallpartial&Mo=18&No=1&Nr=P_CatalogName:BCCA&Ns=P_Price|1||P_SignDesc1&N=0&whse=BCCA&ViewAll=999&Ntk=Text_Search&r=P_CatalogName:BCCA&Ne=4000000&=os0317&Ntt=os0317&cm_mmc=CNEmail_EN_508-_-BANNER-_-9-_-MarketingItemName&ec=1&forcelang=en-CA&Ntx=mode+matchallpartial&Nty=1&topnav=&Sp=S&s=1

Any thoughts on quality or price?

Not sure if some are not reading the thread title or are insecure about their greenhouse use,but many of the posts seem to be anti-topic.Today I went to a well meaning friends place to clean it up as he had moved to Hawaii.Mixed among the soil where a greenhouse had been were little chunks of greenhouse plastic too small to pick up.Many of you can imagine from seeing similar messes.Another down side that Ive mentioned before is that ones food system will tend to become dependent on whatever industrial crutches one provides in the desighn.A great way to pioneer new sustainable lifeways is to desighn the system to function without industial products...but that takes more work and challenges our comfort zones.

I deleted posts again.  I would like to remind folks to not suggest that anybody on permies is anything less than perfect.  State your position without bashing somebody else's position.  State your position in such a way that others can have alternative positions.

The initial topic was about how people often do green houses wrong. The discussion was about when to do greenhouses, and how to do them better. If the agenda is set as "talk about how they suck, and how anyone who disagrees is either insecure or ignorant" then it would be a very sad dialog indeed.

It is my position (and obviously the position of a lot of people in permaculture) that a greenhouse can really improve productivity in a way that is sustainable, though it is certainly case that people often fail to do so. I am afraid that I do not recognize how room can be left for that position if people are only allowed to focus on the failures and not the solutions.

haven't read every post on the topic quite a few though. I call what I have a green house but it is more like a hoop house but not that shape so more really like a cold frame that I can walk into.  I think that a lot of people say green house thinking now I can have a tropical paradise all winter long.  I put mine up for very selfish reasons. living in the PNW it is so cloudy wet rainy and very windy in the Columbia River Gorge I just can't stand not being able to go out side.  So you might call what I built a garden umbrella.  First year was very drafty so put gorilla tape over all the joints and there are a lot since we built it out of lumber and junkyard windows. Used plastic for the roof.  Hint never ever use contractors plastic it will fall apart in a matter of months. There are so many windows that open. With both the front and back doors open plus the roof vents birds often come in and fly around some even made there nest in there. wasps have a few nice homes and even a snake lives in there.  I use straw for the pathways it helps keep the dogs out of the beds since it is so toasty warm and dry.  I have a black trash can with holes cut in the bottom for weeds and cutting not really enough room to chop and drop. the worms have no problem crawling up into the trash can to do there thing.  2 yrs ago had a problem with fungus so I covered the beds with black trash bags on a sunny day and kind of steamed the soil.  Didn't seem to bother the worms they were still there after a few days just a little deeper in the ground. It seemed to do the trick and I didn't have to use any chemicals.  On real cold winter days when I go out to play I turn on a small kerosene heater for 5-10 min and that take the chill off.  Again it's what I have maybe not the best for the plants but they can tough it out for 10 min.  I don't have any thing that "grows"  but it winters over. chard herbs and other greens.   My tomatoes lasted until mid Nov just popping out tomatoes then wham the unusual teens hit dumb me I covered the plants but forgot to pick the fruit. So I had tomato ice cubes. The plant didn't die but didn't get much more off it.  The plants outside had already turned to brown mush. I am sure we could have had tomatoes for xmass had we not had that hard freeze. The condensation problem I had I solved by not watering  at all in the winter.  Water seeps in from under the side walls and that is were I plant for winter crops. Just enough water for the plants but doesn't cause all that condensation.  This summer I want to put power in so I can have tunes when I work.  And maybe a fan just because I have read it is good. Don't know why I need one.  I also use low tunnels in the winter to keep a little extra warmth on the ground. that really helped when I transplanted the leftovers from the outside garden mainly greens.  The chard looked a little weak at first but popped right back up. Every thing else no problem or shock at all.  Haven't tried seed starts out there yet seems like time gets away from me and it's time to go straight into the ground apparently this year won't be any different.

I am working on a greenhouse design to be possibly implemented this year (2011).

This is not just a greenhouse, but a building "system".  

This will consist of a 48'x48' pole barn (where 1/2 of it is commercial greenhouse, 1/4 of it will be living quarters and the other 1/4 garage, utility & storage area).  

Some of the attributes I have in mind:

-Fully insulated poured cement frost-free foundation ~80% slab, ~20% basement.
-100% off the grid (wind & solar to generate electrical power).
-3 systems for heating (including an improved version of the rocket mass wood stove).
-Full spectrum L.E.D. lighting where necessary.
-Super-insulated walls & ceiling (North and part of roof sides).
-Double wall acrylic clear panels on South side wall, part of South aspect ceiling and imperative parts of East and West sides (South ~40% of building).
-Thermal mass storage heated by sun will be accomplished using low-wattage pump circulated tubes filled with calcium chloride hexahydrate & fans to circulate air from upper most level of greenhouse celing using sub subterranean heating cooling system (SHCS) principals.

I will design and build the system myself, using labor and heavy equipment assistance/rental where necessary.

It will be built on family land we have in NW lower Michigan, (USDA p.h. zone 4b) where the winters are long, much devoid of sun and lots and lots of snow - that is often persistent.

I do not have all the details worked out just yet, but I will have the details (including funding) nailed down within a month if nothing else business wise comes up.  

One thing I am considering is starting either another business (farm) or organization (non-for-profit) and will go with whichever one has the highest economic advantage (part of nailing down the details).  

--------------------------------------------------------------------------------------------------

While this sort of system is certainly not "permaculture", I do not believe "permaculture" is a model that can produce fresh, nutritional food for people to eat in this climate for more than 7 months of the year.

This is particularly true considering the current population situation, fueled heavily on fossil fuels.  These fuels aren't going to be financially feasible to extract for long.

A pineapple at our local grocery store costs $3.99 currently.  It is produced in Costa Rica.  How much will it cost when oils fails to be extractable?  This is something I think about a great deal.

There are only two ways to combat this problem: Move South or produce locally.

I think it is wholly possible to grow nutritional tropical fruits and nuts organically in Michigan, but not without a greenhouse - and the best greenhouse is one that requires the least heat inputs.

Where is the suck factor in that?



   


 

Hi Kegs,

you may want to check out

http://www.bioshelter.com/

Darrell Frey (one of my PDC instructors) has been at it for a while

Thanks for the link!

That is very close to the idea right there.

We had a double car garage, built by previous owner, that we only used as storage.  It has a long south facing wall with no shade trees.  We are In zone 8-9 at 3500 ft elevation and usually dry desert conditions.  At a cost of about $2500 we stripped the siding off and installed recycled glass doors.  We installed an insulated wall to the north, giving 12 ft. by 30 ft greenhouse.  We left the overhang with the thought of shading the intense summer sun.  We laid six 55 gal drums of liquid heat sink under each grow bed and installed a 150 gal. fish tank and a 250 gal. fish tank.  That gives a total heat sink of 1200 gal. and grow bed space of 240sq ft. Pumps, gravel in the beds, auto vents, sky lights and solar driven fan  completed the job.  Now our aquaponic greenhose yields lots of winter tomatoes and greens.  Summers are not very productive in there but enough plants live to give biofilter action for the fish.  Sweet taters, peppers and basil are proven summer crops so far. 

Suck factor??      I do not get enough production in summer but plan on building a large reflective surface to improve the light in there.  To get winter production I had to install drapes for the glazing, and supplemental heat.  I use a small oil stove and burn biodiesel for heat.  The water temps often drop to 50 deg. F which is barely enough to keep the fish growing.  The citrus trees have not given any fruit yet.  It was only worth it because the building was already there and not used.

Our local co-op has been getting lots of requests for local figs.Figs only grow OK here.The local small organic farmer next door is going to invest in a bunch of hoop houses in order to grow figs locally.It seems like it might use less resourses for people to eat what grows locally naturaly rather than adjust the local environment via greenhouses to have sub tropical food grown locally in a temperate region.

...and what about October-May?  This is the problem with temperate areas:  Very little grows half of the year.  What does grow is very difficult to harvest and certainly does not produce enough nutrition for the masses of people.

The challenge is population.  Pre-colonial methods of food harvesting will not work for this level of population.

There are few options that will.  Soon fossil fuels are history.  Once the transportation runs out, then what? 

Mt.goat wrote:
Our local co-op has been getting lots of requests for local figs.Figs only grow OK here.The local small organic farmer next door is going to invest in a bunch of hoop houses in order to grow figs locally.It seems like it might use less resourses for people to eat what grows locally naturaly rather than adjust the local environment via greenhouses to have sub tropical food grown locally in a temperate region.

Depending on where you live a properly planned green house can be an asset.
There is occasionaly what I see as a complete dissmissal of a greenhouses worth in areas or zones that those that do not live in those zones do not understand. If you do not live or have not gardened in a cold climate ignoring the wealth of information from a succesful gardener from a different zone that could be passed on to you is a shame.
I've see where both grapes and figs are laid over in the autumn and covered with straw and uncovered in the spring in areas where they could not be grown otherwise.
I have greenhouses and I am perfect according to the word of Paul.  Others live in an area that does not require one and you are perfect too. Greenhouses don't suck, improper usage sucks.

Robert Ray wrote:I have greenhouses and I am perfect according to the word of Paul. 

Clever

Green houses have benefits outside of cold areas.  I am planning on moving to an area that does get cold in winter, but HOT in summer.  Tomatoes for example are a difficult crop there, because summers get so hot and humid that tomatoes will not set fruit well from June to August.  The solution is to start early enough that you can get good fruit set before Mother Nature shuts down the factory.  A later, second crop is planted to begin fruit set as the temperatures drop back into the tomatoes comfort zone.  A green house makes that possible.  Canned tomato products will be a significant part of my winter diet.

Besides extending the growing season, a GH will also extend MY working season.  When temps are in the 40's-50's it will still be too wet to work the soil.  I can get several months of good solid work done inside a greenhouse while the land is awakening from winter.  A lot of this work is work that I will NOT do when outside temps are running 98° with 98% humidity.  It will increase MY productivity by at least 2 months in winter/spring, and possibly 1-2 months autumn/winter as well.  This benefit could slice years off of the time it will take me to reach sustainability.  And provide me with excess seedlings to trade/sell for other things I will need.

To me, a GH wil be one of my most valuable tools.  No, I have no plans to grow bananas in a snow storm, but I will have a place to propagate, breed, and possibly escape the onset of cabin fever.

I have my black currant cuttings I received from the USDA growing in my greenhouse already, those in the garden are nowhere near ready to leaf out yet.
Blueberries the same, cuttings leafed out and looking good.

I concur with many of the issues with greenhouses. however as a plant breeder Id really benefit from having one anyway. Im putting it off this year atleast, perhaps more. I want one that will outlive my grandkids. Some with thick glass like youd find on a tank at sea world or something... okay maybe not that extreme, but I want a thick glass that can stand the weather..... it will help with timing on my bigger projects.

I will agree that greenhouses are great for breeding work and ideally would be used to protect tender seedlings of perennial plants.In that case they are used for a while to establish a permanent landscape-a means to an end.Using them to grow annuals fosters dependence-an end in themselves.This would be like mowing a lawn.A person would need to mow again and again and thus would need a lawnmower as long as that management plan was in place.I use fossil fuels all the time in my quest for a permanent landscape which will reduce my dependence on fossil fuels.

Phew! I've read the whole thread before posting.

I've worked in commercial greenhouses.  My biggest suck factor would be summer overheating.  In the summer, they sprayed (painted) the glass with some chalky white substance which wore off by winter.  And they had a wall of swamp coolers running all summer, too.  I'll bet the owners thought the heating/cooling bills sucked.

I'm surprised no one mentioned Eliot Coleman's book, The Winter Harvest Handbook.  As the name implies, and another poster mentioned, plants quit growing and kind of go dormant when the day length is too short.  But a late planting, in time for them to get to a harvestable size before the short days (depends on your latitude), allows for harvesting through the winter.

Eliot is a commercial, organic farmer.  His movable greenhouses follow his crop rotation.  Fall planted crops, then early spring greens, in the winter.  Then the ends come off the GH's to alleviate the overheating suck factor, and he plants heat loving plants in them, like tomatoes and melons.  When fall comes, the GH's are moved over the already planted winter crops.  Rinse and repeat.  His GH's are not heated. 

We bought our homestead last year.  To avoid other, previously mentioned suck factors, I intentionally purchased a ranch house with an East-West axis (See Intro to Permaculture), and no trees to block the Winter sun.  With just four South facing windows, the interior is 20*F warmer than ambient on a sunny day (I had to learn to factor that in, when lighting the morning fire).  We plan to add a permanent, attached, glass greenhouse after we pay off the house.  In the mean time, I've purchased enough premium film ($140) to last 8 to 10 years, and a hoop bender ($40), to construct a temporary GH.  Now all I need is the steel tubing (~$200), and *time* to build it 

Keeping on topic, one last suck factor, in my opinion, would be to not attach it to your home and make it part of your living space.  As OP's said, it is a wonderful place for the soul and should include the deck or porch.  I don't think I like anything better than being in a warm, humid GH during the cold, bleak winter.  Our GH will be full length on the South side of our house, 40+ feet, but I anticipate 1/2 of that will be used for living area. In my mind, its a blurry line between GH's and passive solar heated homes.

Paul, I admit I am less than perfect.  In fact, my wife will gladly verify that.  But please don't delete my post 

Yeah, weather is a consideration. We had a storm rip through yesterday, and it picked up one end of my greenhouse (12' x 24'  and folded it perpendicularly.  Freakish storm, and many oak and maples in the neighborhood lost limbs (some of which are going into a hugelkultur bed thanks to the local permaculture network!). I think most of the greenhouse is salvageable, I still find it useful for overwintering and propagation, but when a storm like that hits, a certain aspect of the suck factor is impossible to deny.

been thinking about a hoop house made with light fabric which is waterproofed with beeswax. i am

looking for an alternative to plastic. nyone ever heard of or experienced such a thing?

I once read some info put out by the gov'nt of Ontario it said that one hectar of greenhouse costs about $1 000 000 to heat per year. That's alot of natural gas.

No need to heat ala Elliot Coleman

BDAFJeff wrote:
I once read some info put out by the gov'nt of Ontario it said that one hectar of greenhouse costs about $1 000 000 to heat per year. That's alot of natural gas.

Yes, if one is trying to grow bananas or coffee near Toronto, it would be very energy intensive. If the greenhouse relies on solar and compost heat, and is used to extend the seasons for plants that are more cold tolerant, then energy use is rather low (mostly that energy embedded in the materials).

I built two greenhouses last year
11 feet by 22 feet
this one is made from all glass i collected off Craig's list for free
and 80% of the building materials and the roof
i recycled from an old one that was no longer used.

I am still leveling the floor so it isn't operational yet
because i built it backwards in a sense building it
on sloped ground custom style with no foundation.

it's lockable.

the other one is the standard hoop house 14 feet wide by 7 feet
tall  and 75 feet long goes down hill and it is full of 4 inch pots that i collected and they are all starting to pop although i have had some mouse damage especially on the Russian mammoth seed being dug up.

the warmth of 80+ degrees on a 40 degree raw day is especially
welcomed  and gives you a much earlier start. I plant many crops in big
pots that i will simply bring in come fall to extend the harvest.

I get many replies of "wish i had that"  or " i'm jealous" ....ect. but be careful what you wish for because its like having a pet that needs constant care and has to be pampered daily as in watering and manual heat ventilation.

I have auto openers on the "wish list" for vents i have yet to build since i am focused on cranking out hundreds of seedlings for now while its cool as i wait for this week's rain to make the main outside garden a little easier to turn over.

Kelson wrote:
been thinking about a hoop house made with light fabric which is waterproofed with beeswax. i am

looking for an alternative to plastic. nyone ever heard of or experienced such a thing?

Check this out:
http://www.veggiecare.com/

I plan to replace my greenhouse plastic with an extra-strong row cover/remay type cloth. First I have to say, I really like my light-reflecting but non-burning plastic from Greenhouse Bob in South Dakota. He has a great site, with novel ideas, including recycled tires, and very cool rainwater gathering/hoophouse irrigation systems. http://www.northerngreenhouse.com/about_us.htm The plastic lasted many years, and I roll it up on top of my against-the-garage lean-to hoophouse for the summer, so my hoophouse soil gets rain all growing season, and I can regulate the heat by lifting the corners when I need to, since I didn't make my vents big enough. (1/3 of your south surface area is the ratio for vent size I have since read.) I'm using large hardware store clamps to secure it on the pvc pipes at each end. (And the structure is supported inside against snow loads.)

BUT, the cons: it can get too dry in winter, and with spring it can overheat or get too cold as I don't open/forget to shut things. Too high maintenance for the likes of me, without a better automatic venting and irrigation system. And that's too high tech for the likes of me, at least at the moment.

SO, I am intrigued by this strong, greenhouse-grade material sold by nice folks at the first link above. He says it protects to 25 degrees, which I imagine is the same for plastic? Anyone know? But it will release excess heat, and let in some precipitation, so it sounds like a healthier, lower maintenance system to me. I grew some potato-onions under lights (cold frames) this winter, and baked them before it was even officially spring; most of them are bouncing back, but again, how nice it will be to have a self-regulating material instead of the rigid plastic polycarbonate. I may put my polycarbonate lights on top, too, in the worst of winter, to perhaps get more root growth.

As far as is a greenhouse stupid: no, but I am. I put mine where I probably don't get the best light in winter when the sun is lower, since there wasn't anyplace else to put one. My whole little property has very little full sun, so my property is stupid, too. Yet I eats real good anyway, and my stupid hoophouse winters over a few greens and sets magenta spreen lambsquarters and mustard and parcel weeks ahead of my yard, despite the desert conditions created by my neglect. (I love those self-seeders!) I can plant out my winter sown ( www.wintersown.org ) bok choy and cruciferous things while, well, it's still winter and eat the crap out of them by spring. And it often feeds me cherry tomatoes til Christmas. I wish it could be bigger, and a solar greenhouse with thermal mass, insulated walls and soil bed etc. But it still brings me much happiness. I think I would always want to be able to open up my greenhouse to the rain an the air, though.

Another very cool greenhouse design I read in Mother Earth News but can't find again, was by a guy who accidentally discovered that doing waist high raised beds creates a cold sink in the paths, resulting in dramatically warmer soil in the raised beds and 4 season growth for him in some ungodly climate.

If we begin with the notions that all good designs are site specific, and that a really good solution is one that fixes a problem you actually have, then yes, there are a mess of potential suck factors associated with greenhouses. Or virtually any other structure one cares to name.

Since there are probably a thousand ways to do it poorly, and far fewer ways to do it really well, maybe it would be productive for us to focus on when/why to build a greenhouse and how to do it well.

Here in northeastern New Mexico, we have wicked cold winters, and frequent hailstorms in the spring. Before the advent of greenhouses (and supermarkets)  people fed themselves six months out of the year on what they dried, pickled or canned during the other six months. And a bad spring hailstorm could mean hunger and privation due to crop losses.

Some grew root vegetables and tubers and left them in the ground; so long as the ground was unfrozen, this meant they could dig up beets, parsnips and spuds in the winter.

But it's hard to reject out of hand the human benefit from having fresh veg in the winter diet.

A greenhouse can be a wonderful feature if it meets certain parameters - ideally, it faces south, it is ATTACHED to the south-facing wall of a properly oriented dwelling in order to heat the dwelling as well in the winter. That being done runoff from the roof can be cached and directed into the greenhouse. The greenhouse can be constructed largely from discarded/recycled/surplus materials; One friend of mine is partial to old glass shower doors. I would suggest that these be used on the vertical and not for the greenhouse roof in areas where hail is a risk. Another friend dug his greenhouse into a south-facing slope, and built the north wall, plus the bottom half of the east and west walls, from dry-laid stone harvested from nearby. His unheated greenhouse had veg that survived record 25 degree below zero weather this winter.

SOME of the benefits of a greenhouse (which include not only increased winter warmth but also increased humidity) can be realized by more conservative measures, such as intensive use of stone for paths and walls in one's garden, capturing the heat of the sun during the day and radiating it at night. Temporary row hoops can help too.

If you are looking for cheap, recycled materials to build a greenhouse, think of Habitat for Humanity.  They build free houses for many underprivileged people around the globe.  In the US and Canada, they maintain many outlet stores where used materials are sold at very reasonable prices.  A friend bought six sliding glass doors there for about what the big-box store wanted for one.  They also have many new products, ie Home Depot is no longer carrying a certain line of sinks, and donate the ones they have remaining in stock.  The money you spend there will help a worthwhile cause, and save you a bundle of ca$h.

Links to stores in U.S., and Canada:
USA:  http://www.habitat.org/cd/env/restore.aspx
Canada:  http://www.habitat.org/cd/env/restore.aspx?place=can

My suggestion is to look there BEFORE you finalize your plans.  It is much easier (& cheaper) to design around what is available/cheap than to go shopping for specific sizes and styles.


EDITED to add:  Be forewarned!  While you are there, you may see many good things too cheap to bypass.  You may create several new projects around the homestead.