Scott
Sounds like a fantastic project. I'm in the middle of redoing my structure after 22 years and 4 hurricanes. The floods and record low temps were survivable.lol
I've wanted a high altitude greenhouse for many years but decided it was impractile in my climate. So lowland tropical it will be lol
I like to call zone 10 Florida the almost zone as it's almost warm enough and almost not too hot and almost ideal humidity and almost rains enough lol
This time I will have some temp control,a good irrigation system along with a roof that stays put even with 140 mph winds.
Mostly what I've learned over the years is what not to do lol Keep thinking along the lines of "ideal" but compromise works sometimes lol.
Basicly I'm going with my old methods with choice of materials and methods.Certainly don't want to make matters worse lol.
Good luck with your project!! gary

Thanks! I've tried to read about other peoples thoughts and experiences over the years. Much of it has been very helpful. I've also lived in many different climates, from the tropics, the desert and more temperate areas. I've seen the difficulties involved with growing delicate plants in each. My current challenges are prevention of summer over-heating, winter flooding/freezing/snowload, wildfire potential and livestock! Most of the prime building sites that are convienient have been used and the others are not as close as I think they should be. I am very seriously looking at a 33' or 42' Dome. With a Dome vs a box or Quonset hut style, I think that the positives outweigh the negatives. Atleast, thats my thought for now. I would welcome more thoughts and suggestions! Thanks!! Scott

Scott,

I found it interesting that you experienced such a reaction among orchid growers. I grow daylilys and had a similar experience when I began asking questions about growing them in a GH ! Funny thing is that two months later I'm seeing a slightly different attitude than the hostility I experienced.
I use to grow orchids many years ago. Gave up after a freeze (my back door blew open during a storm while I was away from home for a week. All our fuel burned up trying to heat the great outdoors and my house was 30 degrees when I got home) killed over 100 species orchids. Broke my heart and I've never been able to grow them since.

MollyD

Scott
Thgat's a very large structure are you thinking of commercial?? I know you're talking a large budget lol.
Where are you located??
Are you wanting to grow warm or cool orchids?? Obviously lots of them with that size structure.
Have been griowing orchids for over 30 years and even in 10 a structure of some kind is VERY useful.
I can't of course grow the cools and even intermediates
are tough here. Would assume you're talking epis rather than terrests?
gary

I've generally made up my own mind about things! But it is always reasuring to bounce thoughts off of flexible minds as well! I have a friend in Hawaii (I haven't asked yet if there has been a change of thought!) that has been growing, judging, etc... Anyway, we've talked about how ALL the Pros's do it and how I should follow their example. On many of her points I completely agree and relish her accumulated years of knowledge. On other points, I think she fails to see that my "ambitions" are somewhat unique/different, as usual for me. Also, my climate variations (Summer, hot days/cool nights - Winter, cold/rain/snow) are very different!!From her last letter, the power/water/etc has been unreliable at best. Ironically, my last letter to her listed my position/thoughts about not relying on utilities and my location/isolation as well as the inevitable earthquake and prevention of damage to any greenhouse structure. ( Although I don't go into great detail, 'My Page' does tell were I'm located and my grow list. I started out with the Pleurothallid's and other cool growers! (I spent a lot of my childhood in Asia and couldn't resist getting tropicals eventually!) It's rather out of date and doesn't list everything but, it will give you some idea if you're interested!) I can't decide if I want a decadent, lush private rainforest or a survivalist bunker! How about a decadent bunker!! I realize that there are a few here that use one of these. I've also seen the concerns that others have expressed and I thought rather dismissive attitude about them! (On Garden Web in general, not specifically this forum!) Anyway, I like this link as the photos are large and one can clearly see the potential/drawbacks! Nothing is absolutely perfect for everyone and occasional
concessions have to be made. Obviously I haven't fully made up my mind, as I don't have one yet!! Scott

Here is a link that might be useful: 42 ft Dome

Domes are great. Difficult to cover though (without wasting materials) and impossible to expand without building another on the side.

I need a wind resistant structure and a dome would be ideal.

Anyway, my new seed starting house will be a hybrid. Stronger, airodynamic (like a ladybug on a windshield at 90mph!) and expandable. Easier to cover too as only the ends will be tricky, the mid-section will be standard hoophouse type covering.

It is nice to dream!

This link
http://www.gardendome.com/octa_xt/xtm/octa4_xtm.html

shows a greenhouse looking building with a door etc but with a "kneewall" added.

On the link below just look at the first 2 pics, ignore the "sports stadium" looking ones! That has no height extention and is a real smooth shape.

Here is a link that might be useful: My next greenhouse.

I wrote a program years back to make space frame shapes for arbitrary surfaces. When I wrote it I I had no technology to make the joins possible, but since then I've learnt to weld. I think you could make a very nice space frame greenhouse (say 1000m^2) using 1inch tube welding and a suitable film.

Getting a building permit is a different question :)

Here is a link that might be useful: Space frames

nathanhurst,

If you can weld then great! To make a dome or a dome hybrid then the connector plates are the key. Most domes need a mix of 5 and 6 point connectors. The angles stay the same for a set geometric shape but the length of the struts changes.

Um what is a building permit? Ah you live in a place where you don't have to drive to your neighbour!

I was thinking of more interesting shapes than geodesic domes, say like granite outcrops.

Yeah, I live in dense civilisation.

Hi
What type budget for these type structures compared to the inevitable boxes??
I got a few glimpses of the "Conservatory" in a house built by Donald Trump. Looked more like a Attrium or Solarium to me and I couldn't get very clear views but appeared to have vaulted ceilings with polarized glass in
octagonal shapes .I'm sure it was not Maralago as that's all Mediterranean. The entire house was for sale so most of the pix were of living sections. The asking price is 130 million lol gary

If you can do it yourself, with a thin film cover and welded pipes, I imagine you could make a 1000m^2 dome for maybe $20k - $3k for the film, $15k for the tube, $2k for all the things you forgot in your plans :) You could probably halve that if you knew what you were doing.

So your looking for a passive solar greenhouse?

You can do a pit greenhouse.

Or you can live in your greenhouse! This is my dream home www.thenaturalhome.com

Good reading on passive solar design.

I saw on the news here in CT someone built a passive solar gh and looks like it worked very well. I forget what the colddest temp was but they grow tropicals and never used heat for the first year that they've had it.

erlyberd: a good site, but they still make the mistake of trombe wall type design. Bad idea. Still, the idea that dry stacked bricks + fiber reinforced stucco is stronger than mortared bricks is an interesting claim, and is certainly believable.

They claim that they have tested their design in the harsh conditions of high altitude arizona, but in fact that is one of the best locations for passive solar (lots of winter light, regular day-night cycles). I'm more impressed by Thomson, who made numerous 100% solar heated houses in the north east states, where there is regular clouds and much lower average temps. And he built them in the 1930s.

Hi! I've been too busy to check back in and see what is going on. Thanks for the link, erlyberd! I've had several of those books for many years. I remember when I first saw one of the Earthships! I still think that they are wonderfull. Many of these designs were seriously looked at when I in the drier climate of southern California. A major dream for many years has been to build a strawbale post and beam house. We've thought about using one of our current old barns. Much of my delay in doing a greenhouse has been all of this. I research something into the ground, modify it for my needs and do it! The problems with a pit greenhouse is that, I'd have a very nice covered pond for the winter! I actually do want to have lowered areas with a large water feature for both the esthetics, as well as a heat sink. To do so, I'll have to choose the build site very carefully and maybe build a raised mound/pad! I am trying to cover ALL of my bases and it is quite a job! A major factor for me is trying to forsee the future. We're talking about building a house elsewhere on our ranch. I don't want to put a huge amount of effort and construction into something and have to drive to it from the house! I have thought about trying to incorperate it into the house for a wide variety of reasons. As I said, I'm really trying to look into the crystal ball and plan for eventualities. Even with the dome green houses, there are wet climate issues with water leaking in the vents. It's hard to be all things to all people! You end up with unfortunate compromises! Scott

I still say you cant heat that thing at night above freezing without some type of heat. There is no way.

orchiddude: well then you would be wrong. (unless you mean that without (thermodynamic) heat, things are cold, which is an empty statement)

No, what I meant is, I do not see how you are going to heat a greenhouse with orchid temps, at night, with only solar heat. Unless things have changed, it cost to much. If things have changed, them you might be able to. I understand there is always new technologies, but they cost an arm and a leg most of the time. For the average person, I do not see solar. I am not saying it cant be done, I am saying that its not being done where people can afford it. I am not against it, I just dont see it being used around here.

I am not using additional heat in my greenhouse simply because I cannot afford it.

I am not growing orchids either. (see above)

However there are loads of things you can grow where as long as you maintain the temp just above freezing at night and have some warmth in there during the day and decent light.

A fact not recognised in here much is you can sucessfully grow things in your greenhouse even if the night time temperatures in it go BELOW freezing at night.

The key is growing what will survive/thrive in your solar structure. Your structure and its performance dictates your options for whatever plants you grow.

If you start with a requirement to grow a particular type of plant then all the rules change. You have to design a structure that performs to the needs of the plant. That can be expensive.

"horses for courses"

Orchiddude, I never suggested that I could heat with solar only! I said that I'd like to use it 'in addition to'.("Passive/active heat storage and energy generating abilities are a primary plan.") Not only will I save money in the long run, I'll also not worry so much about power outages or the future prices of heating with petroleum products! Actually, things have changed! The cost of solar and alternative energy generation has dropped and the efficiency dramatically improved. Also, it is being done. Perhaps not in your area, just yet. Many of the areas up and down the West Coast, that I've lived in, are either retro-fitting or building with solar(Passive and/or Active) from the start. The only hold back is a narrow mindset and the idea that because fuel prices have been manipulated artificially low, we don't have to worry. You can be extraordinarily efficient by combining traditional building technics and modern materials! The traditional glass house was built for the English and French climate.(And a Lord's budget!!) If you've read some of Eliot Coleman's books, you'd see some of his ideas on growing vegetibles in a simple hoophouse with only the addition of row covers. Many thoughts and ideas from different fields can be used for improvement. I like to take from various fields and combine them into something workable. I alway personalize things for my needs and requirements anyway. I fully plan on using a huge bottom insulated heat sink under my future structure. Having the ability to seal it with insulating curtains at night has been a thought as well. I don't want to cut costs and corners, just to have to pay more in the long run. I want to have only minor repairs and perhaps some upgrades for the next 40 years! There are many structures of this type around the world. Some are from ancient times and the ideas are still advanced! If I really wanted to, I could build one above the barn and have the animal heat contribute at night. We lost a lot, buying into this idea of discarding the past and that only new tech was good. --Climbing off my soapbox now!--Scott

I am all for new ideas, but its hard to see new ideas in the south when no one around you is using them. I am glad solar cost have come down. Maybe in the future I can have solar panels collecting energy so that I can have heat at night without gas. Who knows, but the last time I checked on a system like this, it would have cost many 1000's of dollars to buy and hook up, and the pay back would have been zero to none with the upkeep and extra expense.

This is good news and I hope your idea works. Once again, the biggest factor is making it work for the little people. Its the little people that run the show. Its also like alot of other things, if you need a PhD to understand it you will loose about 90% of the people that want to use it.

I still think its a long way off, until it becomes the norm. This country is so lazy, do you really think they will/want to convert over to different fuel sources. No, its all about money. The day we change fuel, will be the day its last drop is sucked out of the ground. It wont happen in my life time.

I didnt mean to put you on a soapbox, and I would love to see an idea like yours working.

I've been doing some experimenting with some of these design principals on a small scale. I live in North Florida where the problem is that there are about ten freezing nights in the winter --enough to kill tropical life forms-- but the summer is as hot as a good day in Ecuador. So, I've had to design a system around these temperature extremes.

I have built two wooden greenhouses with polycarbonate roofs and ends; each is 30' x 10'. The sides have two layers: an outer panel covered in stainless steel fabric called Zoomesh, and an inner panel made of clear vinyl. I remove the inner vinyl panels in May and put them on in October. So, the sides of the greenhouses are essentially open to the elements in the summer months so they stay cool. I also have a mister system in the greenhouses. Most insects can't get through the Zoomesh, so pests are few.

The greenhouses are about four feet away from two parallel, identically sized sheds. The sheds have galvanized metal sides facing south that reflect sunlight back into the greenhouses.

The sheds have solar water heating panels on the roofs that flow hot water into the greenhouses. The water goes into large tanks where I breed and raise tilapia. The fish wastewater is used to grow plants in the greenhouses. I use unaltered water to grow orchids. I add organic hyrdoponic fertilizers to the water and grow tomatoes and other veggies in hydroponic units. Allt the plants seem to love this warm wastewater. They thrive.

I also have two tanks of red claw crayfish that I'm experimenting with.

I'm planning on building a bigger, more sophisticated set-up over the next five years.

orchiddude, there's more to solar than PV. My friend in Pennsylvania is collecting solar heat at less than a dollar a sqft.

stoned, that aquaponic system is very similar to a few I've been working on here in Australia, one of which featured in the newspaper last week. Keep up the good work - if your system is superior eventually everyone (even orchiddude :) will switch over to it.

I have kept orchids for many years, and I've never seen anything like the success you get with fish wastewater. The orchids are a deep green, grow faster, and produce more flowers than they ever did with fertilizers. It's sort of unbelievable. Anyone who doesn't believe me should set up a small fish tank and experiment with using the water on a few orchids. That will end the debate.

Hey stone, what is the TDS (total dissolved solids) of your water? How do you set your tanks up? Do you start with plain ole water and add clorine remover and go from there are do you use a distilled water or RO and go from here?

I think people can buy fish poop at Lowes and mix with their water. I think I did once and the stuff stunk bad, not sure of the results, I only did it once.

So much to do, so little time.

Hi,

I raise orchids in my pit greenhouse with water storage for a heat sink. But I also have a vented Monitor kero heater for supplementary heat. I use about$400 - 500 in kero per year here in CT. However, I want a bigger greenhouse so I am looking at a solar greenhouse from Farmtek at about 5k. It evidently has a solar blanket and a water wall for heat storage. I would heavily insulate the north wall, and have a brick or concrete floor for heat storage. I might also install a external wood furnace with piped in hot water, since there is a railroad tie wood mill near here and slab wood is cheap. I think I could heat the larger greenhouse for less than I am paying for the present smaller one. Farm tek has a lot of greenhouses and related supplies in their 350 p. catalog. I am not connected to them in any way, just think that they are easy to deal with.

I think one of the recent key insights of plant fertilisation science is that all NPKs are not equal. The form of the nutrients is very important (much like you can't fix anemia by eating rusty nails). The success of seaweed emulsions also demonstrates that plants need more than just the basic elemental nutrients, just like humans need vitamins as well as minerals.

It seems that fishpoo is an excellent mix for plants, presumably this is due to the long shared history of plants and fish.

Thank you for inspiring me to try some more experiments!

Hey stone, what is the TDS (total dissolved solids) of your water?

About 90 ppm straight out of the Floridan aquifer. The water is untreated.

********

How do you set your tanks up?

Aquariums for breeding tanks; large plastic tanks for growing out fish. Air pumps, Eheim filters. The large tanks have both electric (for night) and solar (for day) heating.

*******

Do you start with plain ole water and add clorine remover and go from there are do you use a distilled water or RO and go from here?

Straight well water coming out of the ground at 68 degrees year round.

*******

I think people can buy fish poop at Lowes and mix with their water. I think I did once and the stuff stunk bad, not sure of the results, I only did it once.

The fish water I use has no odor; incremental nutrients over time.

********

So much to do, so little time.

You got that right.

I agree breaking conventional wisdom is frustrating. Also many practical ideas have already been presented and just need to be repackaged for individual projects. I love the idea of combining heat sink (pond) and greenhouses. It is not practical for the space and area I have for the GH and retail space I have at the garden center. It doesn't not mean that I don't want to borrow ideas or concepts that come from it to be more effective in using the space and GH that is there.
I do look for guidance and ideas from this forum and have found several that I am in the process of incorporating or have finished. I do believe that by showing people the practical application of design and use that people will look for ways to conform it to their applications.
I am a strong believer in many organic growing methods yet there are few organic plant nurseries that practice what they preach for economic reasons. I use seaweed regularly as part of my fertilizing regime. I also use alfalfa pellets (cow and rabbit food) because of its growth hormone tricanatrol (sp) and because it is a well balanced 3-1-2 ratio fert. I still use 20-10-20 chemical but use less of it. I have many customers that are using and buying these products based on the trust that I have built with them over months and in many cases years. I don't take their trust lightly and am always trying to look out for their best interest. I don't sell customers products to make a profit. I work hard to sell them products that work and try to make a profit from that.
I feel the same toward the greenhouse that is at the garden center. If I can show to myself how to be more sustainable in its use then I will share this with my customers and try to provide them with the products that allow them to follow my example. Some of it is for a profit some of it is just to make their greenhouses better the profit be damned.
I have tried hard over the last 20 years to dispell myth and offer solid practical and economically viable growing and plant ideas weather it was fruit trees in Hawaii or native and well adapted plants here in Texas. With all your help I can show more practical Greenhouse solutions to people as well. In just the 9 months that the garden center has been open I have had the opportunity to help thousands of people to grow plants with less water and more organic and sustainable practices. I have been sowing seeds of change and am looking to nurture them into thriving plants. Much like all here on this forum wish to nuture and grow their beloved plants. I to love my plants, but also have a love for mankind that says to me how can I help to have people get closer to nature and understand its cycles and not to disrupt it but enhance it where possible and practical.
Nuff said!! I will step off my soapbox now and to all here.... Happy Growing David

hitexplanter,

You have a much better chance of getting close to a sustainable Solar Greenhouse than some of the idiots in zone 4 have. (I mean me!!!)

As to using rabbit food as fertilizer, dog food is great for pumpkins!

Hi,
I remember an institution on Cape Cod called the Cape Cod Ark. It was a solar greenhouse with giant tubular plexiglass or some such clear plastic water filled aquariums. They raised tilapia to eating size using left over garden waste as food. They also had cages of rabbits for heat production and food. Their aim was sustainable food production, and I always wondered how successful it really was, because they are no longer in operation. I believe their experimental farm was near Woods Hole. They wrote a bok, but it too is no longer available.

It must be doable, because once upon a time we fed ourselves without using fossil fuels. The question is whether it can compete with essentially free fuel. My suspicion is that it can, but we need to be sensible about the approach. Chris(in iowa) is on the right track I think.

I believe the place you're referring to in Cape Cod was (is) the New Alchemy Institute. When I was a young man I read about their experiments and was fascinated. Like you, they lodged in my memory.

Right now, I'm doing some proof-of-concept experiments on integrating intensive culture systems (fish, veggies, worms, chickens, etc.) in a way that minimizes the artificial energy inputs into the system on an ongoing basis. I'm on a learning curve, trying to build some sort of productive system with as few moving parts --and a lower potential for failure-- as possible.

My next step will be to build a larger bio-shelter that incorporates what works. I'm in the process of designing that shelter. Basically, I see it as a way to produce veggies and chickens year round and produce meal-size fish and crayfish mostly during the summer months. My goal is to complete it in the next three years.

I'm heartened by the early results. I've got more fish in the pipeline than my family of six can eat, the veggies are amazingly healthy, and you'd have to beat the chickens to death to stop them from producing. My worm bin overfloweth and life is pretty good.

What fascinates me is the potential to incorporate a bio-shelter with a residential design and radically reduce the ecological footprint of an average American family, greatly increase the health and taste attributes of food, and put people back in touch on a daily level with the cycles and pageantry of life.

This is not for everyone, I suppose --after all, the Devil does were Prada, and I don't-- but many people would find it fascinating and personally fulfilling. Suppose you could spend an hour a day in the calm pursuit of tending to your bio-shelter and get the same amount and much better-tasting food that you obtain by spending an hour a day throwing away money at the grocery store? I would suggest that most of us would be happier and certainly much healthier, as would the resources of the planet. That has to make some sense to a decent portion of the population.

So, that's my goal. Besides the laughter with my family, my best part of the day is feeding the fish, checking on the plants, and stealing eggs from the complaining hens. It instills a quiet contentment that is hard to describe, but it is grounded in having a small role in a timeless and elegant cycle of life; a series of infinite trades between strikingly different life forms that have subtle but powerful connections. From the sun to my dinner plate, it delights me as an unearned gift.

nathanhurst,

""Chris(in iowa) is on the right track I think.""

Nope, I am nuts. After many years of building things I have come to the final conclusion that I need to dig a deep hole and build my greenhouse underground. 30-40ft should do it!

One of those ex military missile silos would be great. You can buy them really cheap but the shipping costs are way above what I can pay.

(remembering when someone tried to sell a well on Ebay, and people bid on it!)

Seriously, where I am you have to dig deep and get to the 52F zone.

Or you grow what grows here when it grows and store it in a root cellar (I exist on potatoes, onions, carrots etc plus dead animals and tastless tomatoes and lettuce)

What I should do is dig a hole and make a root cellar and just grow things that naturally grow here and stored them for winter use. But wait, what if I built a small greenhouse above the root cellar? The hole in the ground would provide slight heat so I could grow radishes and brassicas all winter!

Got to dig a hole.......

Aw, the ground is now frozen, I guess all that digging will have to wait a few months....

:)

Aw, the ground is now frozen, I guess all that digging will have to wait a few months....

You not getting the heat wave that we are over in Iowa City? It's been enough to mostly thaw the ground; everything's all squishy again. We've had perhaps 10 hours of barely-below-freezing weather over the entire week, and highs each day of almost 10C. Plus rain. Of course, you're in the northwest, so your climate is nastier than ours. :)

chris, you can be nuts and on the right track at the same time - they're not mutually exclusive. I'm not convinced you need your greenhouse proper to be underground, just have well insulated soil to the appropriate depth.

This is the first that I've been able to post since last week. Although the storm wasn't as bad here, we were w/o power for about three days and I just got my phone and Internet back this afternoon. We do have a generator and that did help to keep the fridges/freezers going.(I didn't hear any others going, but I can't believe that no one else around us has one!) Although I never really lost my focus on not having to rely on the grid, this did re-emphasise the real world practicality of having other means to heat/power a green house. I'm still working on my plans for a huge water heatsink under the whole thing. I've also been thinking about how many ways that one can heat that water. I'm aware of using 'solar waterheaters' and of using compost generated heat. I was thinking about using a solar pump to slowly push water through an outside large compost bin. I've been pulling out wet bales of hay to prevent a barn fire and don't see why you couldn't have a large cinderblock structure and intentionally run the pipes through the haybales. The heat generated is really incredible. With all of the rain, I'm again thinking about using a microhydro system to provide power. I would have to modify a part of my watershed and it would be seasonal. It could be done without that many issues. Also, the cost of small wind generators has come down and they're very efficient anymore. I agree with much of Stoneunhenged's post! I think that I have many of the books on Permaculture and actually do what I can with the ideas. You might like this link and the ideas! I'm still keeping in mind a large dome greenhouse, but I'm also revisiting other ideas both old and new. Scott

Here is a link that might be useful: Translucent dome

I haven't read every word of this thread, so I don't know if this has been discussed (although mentioned)
I own a Growing Spaces Dome....so I'm open to questions if I can help in that area.
I also grow orchids
Kathy

If anyone is interested in doing the math on wind generators, I made up a spreadsheet recently that will crunch the numbers for how cost-effective different wind generators will be. It's a lot easier of a problem than greenhouse heat loss, that's for sure. :) The only thing I haven't done with it that I'd like to is to have the payback periods take into account inflation and how much you could make by investing the money elsewhere during that time or how much you would lose in interest payments on a loan for your capital costs. Right now, payback times are just how long it takes you to produce enough kWh to pay for your capital costs in constant dollars. I could ask my actuary-in-training partner for help on that one to make sure I do it right. ;)

Where I am (borderline suburbia in Iowa -- 4 blocks from a mall in one direction, 4 blocks from a cornfield in the other), I can't make the numbers work out favorably (largely due to non-guyed tower costs and building codes limiting tower height). But if I was out of the city, the numbers would work out pretty well. I could use a lean-up guyed tower which could be built on the cheap, and get it high enough to get the strong winds, plus not have lots of obstructions around it.

Although I'm still considering wind power, I don't think that I get enough reliable wind to make it worthwhile for me. I have been following many of the newer developements in efficient low cost wind power as well as the new thin-film photovoltaic laminates. I want to build a greenhouse system that will run for many years if the rest of the world just disappeared over night! I know that I will be tied into the powergrid, I just don't want to have to rely on it.

Kathy, I would like to know more about your experience with the dome! I've been following them for quite awhile. I have been very interested in either the 33' or the 42' dome! Many things about them I really like. I would do a few things differently and have been not sure about the cost. I have been thinking about making my own out of metal, rather than wood. Regardless, I have all winter to iron out a more complete plan! Scott

Scott,
First of all....what is your Zone?
I'm in Zone 5.
Winters can be below zero...summers in the high 90's.
I have a 15ft dome.
I don't leave my orchids out all year (too cheap to heat all winter)
I put my orchids out from May to Oct.
I do grow in the dome all year, but temperature appropriate things(greens mostly)
The domes are made in Pagosa Springs, Co and many people own them there.
If you call growing Spaces they will gladly put you in touch with someone with conditions like yours....who heat their domes.
Then you would have some idea of what it would cost to keep your orchids out all year.
I would assume that it would be considerably less than a conventional GH (due to solar features)
Kathy

Technically, it is an eight. I put my zone as a seven here. I think that it is a little more complicated than that. My summers get hot(90's-100+). But we get a major cool down at night. (Hot is relative. I spent many years living in Palm Springs!) Tomatoes are difficult to ripen without extra steps taken. Our growing window is probably not as brief as yours, but it's rather short.

Our winters are wet and cold. We do get quite a lot of snow and it has to be able to support the weight. I am aware of the inherent strength of domes. The bigger issue is the intense cold. We have more of a continual freeze than constant snow. If anything, the snow is more insulating.

I have read of issues with the vents leaking in rainy areas. I know that they have to be modified.
I don't think that I could have a pit type w/o being very selective as to where it went. Although, I'm considering building a mound with a potential dome sunk in and the soil(?) higher on the northern side. (I've been making sketches, researching and walking potential building sites.) I'm not talking about it being underground, just having the soil and insulation slope up to the area where the panels meet the frame.

I would love to have it be able to open for the summer. The way that an observatory does! These do seem ideal to have a parabolic reflector integrated in the greenhouse. If the northern part is going to be insulated anyway...
I still think that using wet decaying hay will generate far more heat than a solar water heater will on it's own. It will put out heat both day and night. I really wish that I had local geothermal areas that I could tap into! My water is cold year round. Less than 30 miles from me you can tap into it.

I've been trying to find out how pratical it would be to build one one my own. For the one that I want, $24,000 is quite a lot of money! And actually, I want that 51ft dome anyway.

Scott

51 ft.....Yikes!!!!
Anyway, the vents don't leak. We just replaced the tape that seals the seams because we were having some leakage, but that's after 7 years.
I'm having trouble visualizing your Zone.
Seems like it should be a friendlier climate than my 5.
I noticed on the growing Spaces website that there were 7 domes in Oregon.
maybe they could hook you up with someone near you.
About using metal framing instead of wood....I think wood is a better option.
Doesn't conduct heat out of the GH as much.
I did put a space heater in my dome for 4 or 5 nights last month when nighttime lows were below 10.
Got my utility bill today...seems to have cost me only $3.71
K

O.K. Let me rephrase that! I have read on the Growing Spaces forum about some people in the PNW having problems with rain coming in through the open solar vents. I believe that the solution was to have a rain deflector built over the opening.

The last that I had time to look, most of the ones located in Oregon were coastal. I'm 30 to 40 miles from the coast as the crow flies. Here is a Google photo link! I'm actually to the right of where they're putting the arrow! The photo isn't really up to date either. I've expanded the ponds and tried to naturalise the watershed back to a more natural state. I've been doing what I can to control erosion!

The difference between the basic purpose that they use it for and my needs are the temperature requirements. I don't need to keep it at 80F all winter, but I can't have it dropping below 60F or so. I did originally plan on having a hothouse built inside of a greenhouse from the beginning. That was put on the side for a while and might have to be worked in again. It would be more efficient, as not all of my orchids require constant higher temps. Many of them actually need a variation and/or a seasonal dormancy. I want to have a lot of space.

I know how easy it is to outgrow something. I also plan on growing vegetables all winter and will use it to overwinter plants from outside. I have huge pots of lemon grass, citrus, etc. I eat virtually all organic. I was raised that way anyway. I stopped eating all fast food years ago because I got so ill from it. Lately, I have been finding out that there are many things that I'm very allergic to. Virtually everything that has been processed. I always thought that I was sensitive to GM foods. I'm finding out that it's pretty much all glutens and several other common things. The gardens do well all summer, but I want to grow a lot for the winter as well. So, I'm trying to kill as many birds with one stone as possible.

One of my primary concerns has also been about earthquakes. I know that it's just a matter of time before we have a big one. I'm not paranoid about them. I've spent my whole life living on the Pacific Ring of Fire around the world. We had a major fire here four years ago. It demonstrated how easily my area would be cut off from the outside. Even the major roads are tenous at best! I like to prepare for the worst and hope for the best. Even if nothing happens in my lifetime, I'll have one hell of a greenhouse!:) Scott

Here is a link that might be useful: My location

I never have an open vent problem here when it rains.
The solar vents are set to close at 80 and the rain always cools things way below that.
My elevation is 6000 ft
I grow veggies all Winter, only using supplemental heat when night temps are below 10
I'm an organic grower....and a vegetarian.
Can't help with earthquake info, but I know the dome is very wind resistant We have fires here but not in the middle of the city (where I am)
I checked out your weather on Weather Underground.
Right now you are warmer than me and quite a bit warmer at night.
The one problem I can see with your climate is lack of sun.
We have a lot of it here...just not today!
K

Interesting nathan, I thought trombe wall was a wall built against the south facing glass to collect heat? But was a form of active heat ecause you need a fan to get the heat out? Not sure. Perhaps you can correct me. Any links for Thomson?

I thought the basic idea for passive solar was glazing on the south side, high thermal mass and good insulation? Why are others talking about high cost solar technology here?

Water is best at storing heat and stone/cement would be second. Right? How would cord wood stack up as thermal mass? It seems like a low earth bermed shelter would work best. Long and narrow with lots of south facing glazing.

If your earth bermed/underground shelter keeps near the earth temp of say 50 degrees then you just need to add 20 degrees to make it comfy.

The problem with trombe walls is that we don't have glazing good enough to make them work. They tend to be worse than plain insulated walls on average. There are much better designed approaches with narrow, rapidly heating collectors, and the storage insulated away from the cold. Passive can work in some climates, but active can work for a lot less money and space.

Wood would be a poor thermal storage, as it is mostly carbohydrates, which have a poor specific heat. Not convinced about the south glazing - in cold climates it will suck all the heat out of your house in winter, in hot climates you'll bake. I think a better design would look more traditional, but perhaps you make the entire roof out of polycarbonate and use shade cloth inside to absorb heat which you move down with a fan(In summer you might open a vent to release that excess heat). A similar design on the wall can self circulate when warm by using a little damper made from lightweight plastic film and a mesh (the mes stops the film from swinging open in the opposite direction). In summer it would be shaded.

If your earth bermed/underground shelter keeps near the earth temp of say 50 degrees then you just need to add 20 degrees to make it comfy.

If your earth bermed shelter _keeps_ you at 50F, then you won't be able to heat it to 70F. So you would have to insulate the house from the ground, at which point you have to wonder why you built it there in the first place :)