Very high on my personal priority list (right after a small house to live in) if I get rural land is the creation of a four seasons, year round, "advanced" greenhouse. It may or may not be linked with an aquaponics fish raising system, but will probably involve a thermal mass of water even if it isn't used for fish raising. (even if just for a hot tub or small pool to swim in, warmly, in the middle of winter :)

By ADVANCED though I mean things which are outside of the norm for what I commonly see for greenhouse designs. A greenhouse which is say more surviveable (huge amounts of glazing damaged by hail, or vandalism in poorer areas), which uses only passive energy designs even in colder climates like southern canada or the northern midwest, and which keeps costs to a minimum with the maximum use of scrap or recycled materials since a 'perfect' greenhouse nobody can afford to build is no use to anyone.

To share a few of the ideas i'm currently exploring:

- Automated production, the best greenhouse is one that doesn't require you to work in there every day. Ideally i'd like to be able to go away for a week or even a month and have everything doing just fine. Maybe even several months just showing up to harvest for a totally automated greenhouse. My current life requires me to be in the city, the best location from a health perspective of nonpolluted air is going to being the country. (unless natural cheap air filtration can fix this problem as well or some kind of closed air cycle of already filtered air?) This would include ideally either remote monitoring or/and control of protection measures, for instance something to protect the glazing from hail if i'm 100 miles away.
- The use of 'pop bottle' glazing http://www.123-greenhouse-gardening.com/building-a-backyard-greenhouse.html my main concerns are possibly outgassing of PET plastics and UV degradation of the bottles, although I hope they would last at least 2-3 years before requiring replacement. Health concerns over outgassing means I may not use them on the inside where they contact the plants but there still can be uses for them... for instance a transparent 'overshield' that could be pulled over the outer glazing to provide some physical protection while still allowing most of the light to pass through. It would also provide at least some vandalism protection though not from a concerted attack obviously, but something from the randomly tossed rock or somesuch.
- The use of recycled windows. These are often single pane or unglazed, available free whenever someone upgrades windows. Adding plastic bubblewrap achieves almost all of the benefits of double glazing (if they were single before) even though you cant see through them as easily. Several layers of bubble wrap gives more insulation with even less visibility. The wrap would be on the outside due to the same outgassing fears. The lack of visibility may actually be GOOD to reduce break in targets as long as the light levels are high enough to still support growth of anything you want to grow. Which brings me to...
- Reflected light and light/heat portals. One idea i'd considered is the use of either flat mirrors or even parabolic troughs to gather and concentrate light, beam it in through a much smaller area of glass, and then re-diffuse it inside the greenhouse. This means you could have say an R20 arch of well insulated earthbricks, with small windows... single panes that you quad stacked to get four panes of insulation on the cheap in a single glass unit... but only taking up say 10% of the area of the whole structure. All the sunlight for the structure is beamed in through here, so that you dont lose heat off all that glazing. Ideally I would like to be able to raise citrus trees in the middle of minnesota winters. This normally would require about 6 hours of equator level light. The concentrators restore the light to equator level intensity at the minimum, even through bubble wrap, bottles and other obscurant insulation, so that at least during the hours of sunlight you do have it is intense enough... then supplementary grow lights only have to be used perhaps 1hr in the morning and 1hr in the evening, making this more feasible. The main problem here is rediffusing the light without creating hotspots at up to equator levels of intensity.
- Moveable insulation. Lots of windows means light and heat in during the day... and lots of low insulation loss at night. Coatings are one attempt to control and minimize this... but simply covering up the windows (perhaps some automated covers even) with insulation after the sun has shone for the day and you've gotten all the gain you are going to get for the other 18-20 hours of the day means that even in severely cold winter areas you should gain more than you lose even with cheaper windows. Especially if you add the additional reflectors. (to add heat at least if not extra light, if too much light burns the plants, or it cannot be satisfactorily rediffused very well... in that case just heat water or air and store that in the thermal mass in the greenhouse)
- Automated cleaning. I would like the idea of using scavenged junkyard windshield wipers perhaps, or something else for the "automated greenhouse" so that you dont have to go out there constantly. Or maybe some automated cleaning spray to wash off blown wet leaves or whatever might get on there. If the greenhouse is 100mi away it is not easy to do what it wants you to immediately.
- Sunken floors and insulated thermal masses. Read up on Annualized Geo Solar and Passive Annualized Heat Storage http://harmoniouspalette.com/PAHS-retrofit.html which is a way to use the summer sun to warm things in the winter, and the winter cold to cool your house in the summer via a seasonal thermal store averaging out year round temperatures. This would require moveable insulation at the least to avoid mass loss of energy in the winter but should otherwise be feasible. Alternately the additional solar gain made possible by reflecting mirrors and such should hopefully make up for the enhanced heat loss of a greenhouse.
- Use of compost heat, one of the aquaponics designs uses this alone to heat an above ground year round four seasons greenhouse. This could either replace the need for a sunken floor, enhance it, or add additional heat without the expense of extra solar mirrors.
- Multiple internal microclimates. My intent is to used raised bed intensive gardening combined with "thermal gradients" - for instance in the middle of the greenhouse you might have an area which is 90 degrees year round for growing tropical herbs. Outside of that, with an internal barrier between them is a 75 degree year round gradient for more moderate plants. Outside of that a 60 degree gradient etc etc. I want to grow chinese medicine herbs which come from MULTIPLE climates, there is no one single growing temperature or light intensity which is perfect for all of them. Indeed some of them need near freezing cold even. By having somewhat thermally separated sections, with the heat from the hottest leaking in part to the cooler sections intentionally (possibly even a greenhouse within a greenhouse if necessary) as well as different levels of light intensity (via reflected light or augmented grow lights) and of course potentially different soil ph and compositions made possible by separated raised beds which might have their own separate fertilizer for instance, I want to be able to grow stuff from anywhere in the world regardless of it's origin climate. This includes plants which favor colder than normal summer temperatures or even want year round near winter temperatures, for instance some of the best ginsings grow in the shade of a mountain on the china/korea border. I'd like to recreate that here if possible since so far attempts to grow that species in 'nicer' warmer conditions do NOT yield an equivalently effective medicinal result, the plants NEED that environment to bring up whatever mineral uptake or whatever it is that makes them so effective. (the use of PAHS/AGS above can favor cooler than average temperatures, and the use of intentional shade can also assist this. Such a deliberate "coldhouse" would also be used bordering refrigeration or freezing space for the living space/country house as well.) Separate thermal stores insulated from one another may be used. (which is no more complex than sinking styrofoam down however many feet is necessary to cause the gradient to occur.) Call it my own little Biosphere 2.
- Integration with housing designs. I see no reason to have such a nice warm room go to waste. Whether it's simply placing an outdoor pool inside the greenhouse, or just having a sunroom or sitting room attached to it, or using the plants to have "a view" as a part of the atrium for an underground house, it makes sense to me to make this integrated instead of a totally detached structure. It could work in either way of course, but there could be additional synergies or benefits to doing it this way. Simply opening a window from inside the house to the greenhouse could give a little extra heat flowing out there on real cold nights for instance, if the existing PAHS/AGS design isnt enough. Or you could build a fireplace with openings to the house, and to the greenhouse, opening the latter even if the former is closed for extremely cold times if for some reason all the above thermal storage designs fail, or some unexpected accident (like broken glazing during a blizzard) screws up the passive system. The "4 season coldhouse" would probably border an icehouse doubling as both large walk in freezer space and refrigerator space with the same above and below freezing temperature gradients designed into the hothouse, and it would probably be located on a different side of the structure for obvious reasons.

Those are some of my ideas which i'm (slowly) working on and fully plan to experiment with and try out in the future... do you have any? :) Or have you any comments about mine?