Experimental greenhouse build. Looking for suggestions.

I have nearly completed the brick walls around it,  but the internals are still to be decided.  Ground is higher east and north of the greenhouse,  and its 9 wide by 12 long. Ill have the whole floor covered in concrete paver slabs to prevent rodents burrowing under. Brick or wood for the inside walls of the planters?   The back wall will have a "dripwall"  (water dripping down on sunny days to capture heat and bring it under the soil)  there will also be abut 6 inches of water under the planter in and this water will be circulated around the planter.  (I use an airlift pump to move the water).  I also plan to pump air through a 3 inch gravel filled pipe to under the soil in the planters  with a computer fan powered  by a solar panel.  This is to capture heat from the warm air for the cold night and also hopefully to condense moisture from the air onto the gravel.  Roof will be 5 glass panels.  2 longways and 3 sideways so it can have the steeper slope to the north or to the south,  which is better?    Experimental greenhouse
Thanks Brian white Victoria BC Canada

You are probably better off doing something like a solar water heater to capture heat and circulate it into the greenhouse. Having constantly dripping water seems like an invitation to either algae or mold or both.  

If you can avoid wood contacting soil, then I would recommend doing that. Wood+soil+water=insects and other pests.  Most treated lumber is either treated with something nasty like creosote or arsenic or it has been treated with a copper solution that does not work as well and is a skin irritant, not really what you want in small area like a green house where you will be touching your planting beds a lot.  

If you do not mortar cinder blocks into place, they can be staked into place to create beds.  They are inexpensive, re-usable, and should hold as long as they are not more than 3 or 4 cinder blocks tall.  

Your link just goes to the Google. Might you be able to attach photos from your computer or phone using the "attachments" tab at the bottom of a new post?

Where are you located in the world?  What works in Arizona may not work in Minnesota...

Sorry, I haven't been here in a while so things have changed a bit.  I popped in a few pictures of the work so far and a diagram of the planter layout in the greenhouse as attachments.  I used to be able to do images in posts ( I thought).   I was really hoping to have a working greenhouse by Christmas but it has been a bit rainy.  Anyway,  here goes with the photos.  
Brian

Here is the roof question. Which is better,  the steep side of the roof to the north or to the south?  

Where are you located in the world?  Snow load, latitude and winter cloudiness all come into the equation...

Mike Haasl wrote:Where are you located in the world?  Snow load, latitude and winter cloudiness all come into the equation...

Hi, Mike, Victoria BC  About 48 degrees north. I'll be putting on the roof pretty soon, (if the weather dries up for a day). I'm currently thinking of putting the steeper side facing south.  I think snow will slide easily off the glass. And if not,  I'll be out there with a broom.

I like that idea as well.  Shedding snow from the sunny side is a good idea.  Plus if the snow sticks to the flatter North slope it gives you more insulation.  I presume you might be cloudy a fair bit in the winter?  If so all the glass will be helpful.  In a cold and sunny area, limiting the glass on the north side (and E/W) helps to give more insulation and less heat loss.

Mike Haasl wrote:I like that idea as well.  Shedding snow from the sunny side is a good idea.  Plus if the snow sticks to the flatter North slope it gives you more insulation.  I presume you might be cloudy a fair bit in the winter?  If so all the glass will be helpful.  In a cold and sunny area, limiting the glass on the north side (and E/W) helps to give more insulation and less heat loss.

Thanks, Mike,  the north side is a few feet away from my boundary fence.  It will have a higher wall before the glass (around 3 and a half ft and then glass).  Because the lower part is not going to get light easily anyway.  I put on a ridge board just to see how high and the slope on the north side is 20 degrees and on the south it is 30 degrees. I was maybe going to put the roof on first and then the final windows but I changed my mind.  Windows will go in first then the roof.  I'll silicone them into their frames and it will stiffen up the structure Plus there's wood framing  at roof level above the windows so it is much easier if its done first.  Tomorrow is another rainy day,  but perhaps there will be gaps in the rain.   Thanks for your input,   I ended up putting the steeper side to the south.  
Why do people put saw tooth fancy stuff above the ridge? Is it to deter birds or just to look pretty?  
Thanks Brian  

If you mean the fancy spikes like on this greenhouse, I suspect you're right and it's to keep birds from pooping on it and possibly it's pretty...

The traditional victorian ones were often tied into lightening strike grounding.  The ridge decorations were often metal and tied to ground through the lightening rods/fancy finials that were tied to ground straps on the old metal and glass greenhouses.  Stopping the birds from pooping was a side benefit.  Since the original Victorian designs were often tall, warm, and metal so they were quite the target. They were large and elaborate and used to grow everything from citrus trees to tea shrubs to orchids.

https://www.pinterest.com/pin/15058979976449202/

Here is a diagram that will be pretty close to the plan for my taller (North) planter.   There will also be pipes or tubes in the soil to circulate solar collected water (like a radiant floor)  and also some pipes in the soil or water chamber to send warm air from high up in the greenhouse,  to extract the heat and store it overnight.  

I've been a bit lazy and weather is horrible so I haven't got much done. However, I did this little drawing to show how the heat storage might work.  Its probably mostly to capture afternoon heat and put it into the soil or water both to prevent heat stress in the afternoons, and to provide the equivalent of a "warm bed" overnight.  Figures are close to correct for my  as yet unbuilt greenhouse.  I'll power it with a computer fan connected directly to an old solar panel.  

Lisa Sampson wrote:Most treated lumber is either treated with something nasty like creosote or arsenic

With the exception of railroad ties and telephone poles, most treated lumber doesn't used creosote anymore, thankfully. It's still something to be wary of when using reclaimed wood though.

or it has been treated with a copper solution that does not work as well and is a skin irritant, not really what you want in small area like a green house where you will be touching your planting beds a lot.

My personal experience with ACQ (a specific copper treated method) is no skin irritation for me or any of a half-dozen people who's interacted with my garden beds, and the beds have lasted for at least five years so far, and look like they'll go much longer. A few screws have come loose from softened or slightly warped wood, so now I'll use longer (3 1/2") screws and more of them. Essentially, from 40 rectangles of 2x10s or 2x12s, about five corners came undone over five years (5 corners out of 160 corners).
I'm excluding a garden bed that was hit by a tractor (-_-).

Mine aren't in a greenhouse where moisture is trapped, but they are filled with dirt on automated irrigation, and I get a decent amount of rain in spring and fall, and plenty of heat in summer.

Other copper treating methods vary in quality. For example, I've yet to see how well AC2 works (Menards) but bought a decent amount for an arbor. EL2 (Lowes) sounds scarily poor quality. I'm really happy with ACQ though. Different big box stores use different treatment methods (depending on the lumbermills they source from), and we have to watch out for the distinction between "ground contact" (good) and "above ground" (poor) treatments. They usually make that distinction on their websites, e.g. "intended for burial or direct ground contact" or "not intended for direct contact with ground".

I'm super not happy with Coronovirus literally more than doubling the cost of wood, though! Seriously it's lke 250% the regular price near me, so I'm putting off some projects to next year.

I will be most likely using pallet wood for the insides of the planters, I'll only use wood from new pallets and it'll be marked HT, (Meaning that it is made with heat treated wood), and any wood I mess up breaking up the pallets will go in the fire as soon as its dry.  Its likely all the inner walls of the greenhouse planters  will be made of wood. (I almost ran out of used bricks). They are sacrificial.  I don't mind if they slowly rot in place, because when they do, they will end up in the compost bin or buried under a vegetable patch.   There are so many ways to transfer heat from the air above to the water under the greenhouse,  I'm a bit at a loss to figure out the best ways.  Maybe, I should do a reply with a rough diagram of several alternatives?    One is having some sort of  "radiator"  near the apex of the roof (inside) and pump cold water through it in a circuit that also includes a run of copper or alu pipe under the water in the chamber under the planter.  Something on the roof like a reused automobile radiator? and it'll still need a computer fan or bigger to blow air through it and it'll need something  to wick away condensate and also probably an inline rotary pump to run the water through it.   Any thoughts?  Also, how hot will a 10 sq meter  (107 sq ft) greenhouse  typically get?   Anyone have their shaded thermometer readings from a small greenhouse?

I think I like the idea of moving the air down and running it through either the soil or the water via a corrugated air-tight tube.  That seems simplest.  If you use a radiator up high, then you need to pump the water up there and you'll need a beefier fan.  

Pouring rain all day today so I was looking up more things to experiment with  and adding CO2 to the greenhouse is a big one.  If the daytime CO2 levels can be raised from 400 ppm to 1200 ppm in the greenhouse, then there will be a major boost in plant growth.    So, my greenhouse is 10 sq meters and the task for the day was to internet research how to do it.  The plants in this size greenhouse likely could use up to 0.2 Kg of CO2 in Winter and around 0.3 kg of Co2 in the Summer.   Here are some of the ways to get 0.3 kg of CO2 into the air in the greenhouse. 70 kg human resting in the greenhouse for about 10 hours.  Or  Burn 200 grams of wood,  or have an enclosed compost bin attached to the greenhouse and add about 3.5 kg of yard waste to the compost every day in the summer.  Chickens or rabbits in the greenhouse  or in an enclosed shed attached to it, are other options,  or  maybe a kennel for the local raccoons. (they exhale as they sleep), so just suck air out of the kennel into the greenhouse.  So,  I'm not sure if I can get 3.5 kg of weeds per day.  Also,  I haven't put all the glass in the north side of it,  and maybe I can put a blue barrel composter in one section instead of glass.  (Can't be wood because the rodents will make holes to get in).  I'll take a pic of how I do compost in a blue barrel,  maybe tomorrow.  Another idea might be a sheet metal compost bin on the north side. (Again,  necessary to be both rodent and air  circulation proof.   (Because the CO2 from the compost must be directed into the greenhouse not into the outside air).   Anyways,  what do you all think?

I did the compost in my greenhouse for two years with the aim of getting heat from it.  I didn't get that but I did get a bunch of smells and possible questionable gasses.  So if you get CO2 you'd also be getting other gasses that you might not want to breath.  Plus more rot organisms.

The raccoon house would be very creative.  Allow them into a box that is within the greenhouse but blocked off from it.  Then you might get some droppings for fertilizer as well.  Maybe a cat or possum or other critter would want to live there instead - no biggie.

someone just suggested mushrooms in another place where I posted about the greenhouse.  So, I'd probably do that in a sealed box outside the north wall.  and pipe the greenhouse air in and the mushroom gasses out. Anyone know how quick mushrooms decompose wood and give off  CO2?

I know nothing about greenhouses, but I do know about wildlife poop! I would highly recommend to NEVER use wildlife feces for "manure" and exclude any meat eating pet (cat, dog, ferret etc.) feces.

Raccoons and most wildlife carry parasites. In particular a roundworm called Baylis ascaris can, in very rare instances (must be incubated at just the right temperature for 17-21 days - green house would be perfect - and accidently ingested) can cause blindness and even death.  Cat species carry a host of zoonotic parasites that can seriously harm and yes, also kill a human - toxoplasmosis to name just one.

Manure from "vegetarian" (horse, cow, goat, rabbit, llama etc.) animals that has aged, for whatever reason, is viewed safe - I assume that the heat produced by decomp kills the nasty ones.

With it being so close to the neighbor, I would ensure water/snow runoff will not be an issue for the fence - replacing the fence once the green house is built could be challenging. Proactive replacement of existing fence section behind greenhouse may be wise. I suggest posts with elevated "feet" (concrete and saddles?) or straight metal posts faced with metal or other moisture immune material where the green house will shed moisture.

Don't forget to include ventilation for when hot in summer. Do build strong enough for our rare 2ft dump of nasty, wet, heavy snow - it would be a shame to do all this work and have it collapse and shatter all the glass.

I reached out to a few government organizations and professionals and one lady couldn't answer my questions about the CO2 output from Compost so she passed it on.  Turns out one of the organizations I asked is consulting with a large composting facility to implement pretty much the same thing on a far larger scale, of course.  (using the compost's heat and CO2 in a greenhouse).   They will be using Co2 monitors to keep their levels optimum.  Anyways, I feel a positive vibe because someone else is attempting the same thing.   I looked up CO2 concentrations in typical situations.  1200 ppm are typical in new LEED Platinum apartments according to one statistic,  Single occupant cars are in the 4100 ppm range. And classrooms are around the 1000 ppm range.  So, I think we are good! I guess it might be an idea to invest in a CO2 meter because it is experimental, after all, but more and more, it looks like CO2 from compost is doable, and pretty safe,  Just need to scale it right.  Probably have to process the air,  or send it under the planter straight out of the compost bin to filter the smellies out of it.  

Just a couple of pictures and  diagrams.    I wonder what type of sensors and data loggers aren't too expensive and can still do the CO2 humidity and temperature measurements accurately enough for this project. I was going slow, due to weather and also Trying to decide what is best for the compost/CO2 generator. I'll be using a different sheet of glass than originally for the back of the greenhouse. I'm now glad I took my time.

The greenhouse project hasn't exactly been going quickly.  I did learn a few things,  Easiest way I have found to cut perspex/plexiglass is with a zip disk on a 4 1/2 inch angle grinder.  When you do it against a straight edge of wood, and at the right speed,  some of the plexiglass converts to fiber and you just have to stop and remove it a few times as you cut.  Also the plexiglass quickly "glues to the straight edge so  you get a nice straight line.   Back and forth a few times and you will get a pretty clean cut.  Then just crack off the bits that are stuck to the edge and your piece is ready to go.   (I'm useless at cutting glass so that is why I used plexiglass for the angled windows).   I made a complicated layered frame with cedar for the glass for the roof. Then stringlined across the top of the roof  to make sure that the thing was flat enough to put glass on. Then adjust the braces till the wood kisses the string and its all flat ready for the glass.    Dewalt table saw is excellent for doing that work.  I've never done carpentry so I am learning as I go. I didn't use standard 2 by 4's for the roof because I was afraid that they would warp as they dried and I wanted to support the glass all around its edges on at an inch of wood. The glass  sheets are 70 inches by 46 inches. I'm going to get help to lift them in place.  South side of roof has a slope of 30 degrees while north is 19 degrees.  Any advice on data loggers?   I want  temperature and humidity and CO2 ppm.   At least 2 temp readers need to be able to go to 0.1 degrees C and to be fairly fast at measuring.  This is for the dripwall at the back (the solar collector on the north wall inside the greenhouse.  And also maybe to reach down to the water chamber below the soil (So it probably needs a 2 or 3 ft wire to go to the probe) and also to measure temperature anywhere there is condensation. Where the air is moving through pipes in  cold water, etc.  When there is condensation, there is heat released.    I need to be able to measure that release of heat or to measure the amount of water that condenses out of the air as it circulates through the "cooler"  Anyways,   I really wish I didn't have such big pieces of glass (but they were free!)  That's enough for now, I think.  Brian    

most of the outside is cedar.  Do I need to paint it?  

If you are BC wet coast, then likely you are using local cedar designed for our weather, prized by the indigenous for it's stability in the wet. It will change to a more silvery color without treatment - likely with the current weather, the wood is too wet for a finish now, anyway.

I popped the last sheet of glass on the roof yesterday and siliconed it in.  Pouring rain today and probably tomorrow too.  I might do the gutters tomorrow or set up for the pond rubber under the planters.  Depends on the weather.  I notched the wood before siliconing so that the silicone will Bite into the wood.   Silicone sticks forever to glass and metal but eventually the stick stops on wood.  So the little cuts will prevent the glass from sliding in 4 or 5 years time.  

I meant to show the notches that prevent the glass from slipping down (once the silicone sets).  Here they are.   I use silicone because it sticks really powerfully to glass or metal.   I notch the wood because the silicone bond with wood eventually weakens,  but if it has all those little "teeth" biting into the wood,  it still won't slip down even when the bond breaks.  

I got a path down (I won't grout until much later) and rat proof trench dug (Mortar about an inch thick so that rats and roots won't puncture the pond rubber|) and I calculate that at least 500 liters of water (about 2 and a half blue rain barrels worth) can be stored under the planter.   (I'll have about a foot of soil above the water (on a wooden floor/ceiling)  in the planter.  

I did a video about the greenhouse.   Things are at a stop due to snow.   I'd love some feedback about dataloggers.    

I just ran across a Master Gardener in California who buries a black plastic gallon pot at least 6 inches into the soil, in the bottom of a tomato cage, fills that pot about half way with compost and composted manure, plants out around the outside of the black pot/cage, then waters through that black pot, putting compost tea down into the root zone and saving a lot of water.  That is a nice separation of questionable-but-necessary-to-the-soil amendments.

For what it's worth, no animal feces is "safe."  It is what it is, nothing we should handle or get on our food, even if it's been composted.  

Lettuce/spinach/greens recalls happen because cows or some other grazing animals have pooped in a river to the degree that then downstream that water goes onto greens by overhead watering and leaves behind bacteria that causes humans health problems.  

In our gardens when water splashes up on greens from compost or even composted manure can cause the same problems.

Mulching with dry leaves or straw/hay/mowed weeds helps to stop that.  Thoroughly washing of all edible foods is the most important step.

I need to join a pipe (half inch or 3/8 inch) into the pond rubber,  and also into a 4 inch white pipe (sewage or wastewater pvc pipe)   Any suggestions for the best methods?   I like "alternative" ways of doing stuff.  If I don't hear back,  I'll probably do something with rubber bungs for beer making. They take a 1/4 inch tube,  its a bit hard and tedious to enlarge the hole but it can be done.  The melting snow is still slowing down the build but I made some progress today.    Thanks in advance,  Brian.

Where is a good place to get temperature, sun hours and precipitation per month for different cities?    I can't seem to find them all together.    For instance,  Victoria has lots of sun (but very little sun from October to March)  This type of thing influences greenhouse design.   I have heard that Calgary gets way more sun in Winter than we do.  So, even though its colder, they might have an advantage because they can insulate a greenhouse really well and still get enough light just from the south.  But because its cloudy in Victoria in  winter, the light comes from all over the sky so if you insulate well,  you end up with a dark greenhouse that gets an occasional sunbeam maybe for a few sunny hours per week.  

One experiment is nearly ready,  I measured temperature of the air going into the pipe that goes through the soil,  and coming out.   But I have no system to measure airflow yet. I might get that up and running tomorrow.  Just got to find a dandelion or thistle parachute and try measure the air speed with it. The pipe goes about 9 feet under the soil. I used a computer fan powered by a solar panel to blow the air. After measuring the temperature,  I bought some "temporary plastic downpipe" and mounted the computer fans above it so tomorrow, it will be drawing the hot humid air from near the roof down and through the soil.  Maybe, there will be a degree or 2 of extra heat and maybe an extra few percent of humidity up there.    For tomorrow, I also have the air pipe hooked up (the black plastic pipe) that goes right down and under the water.   I'm really hoping that one gets cold enough so that there is measurable condensation there.  That would be awesome.      

With the exception of railroad ties and telephone poles, most treated lumber doesn't used creosote anymore, thankfully. It's still something to be wary of when using reclaimed wood though.

I left some tobacco plants growing  in the experimental greenhouse and it seems that aphids have disappeared over the course of the last couple of weeks,  is it possible that the nicotine from the plants got into the air and killed the aphids?   There are many aphids outside the greenhouse on my other plants.  
Brian

Did you do something that would have interfered with the ants that typically coexist with the aphids? Getting rid of the ants gets rid of the aphids.

I doubt there was much nicotine in the air from the tobacco plants -- unless you were smoking them =)

Tobacco doesn't just have nicotine,  there are also other chemicals.  I haven't done anything else.  I don't see spider mites on my tomatoes either.  The greenhouse wasn't insect free at the start.  But it is now,  Also, there are many ways for insects to enter the greenhouse but there are no wasps building in there, etc.  All I have different is the air circulation system |(that cools the air a bit and extracts some moisture) and the tobacco plants.   The air circulation certainly didn't inhibit insects early in the year.   Maybe there is enough nicotine to deter insects?  I currently have the tobacco hanging up to dry so that they can continue to inhibit the insects in the greenhouse.  Nothing else in there that is known to be an insect killer.

Last photo in the previous post was spider mite damage (in my other non nicotine) greenhouse.  No evidence of this in the tobacco greenhouse.  I can tell its spider mites because although the spider mites are too tiny to see,  the predatory mites that eat them,  are visible and moving.  

Here is a video of the experimental greenhouse on October 9th.  I've done my best to keep calm and not shake the camera too much.  I think the greenhouse has done ok.  Even though I am not totally happy with the watering system, it sure beats hand watering. I'm pretty sure the tobacco is what prevented the peppers, tomatoes and others from setting fruit early in the year. (after all,  I took cuttings off the tomatoes for my other greenhouse and they set fruit over a month before the parent plants!  The heat moving systems and condensation harvesting are really a cold season thing, so,  as soon as I pull out the peppers and tomatoes,  I'm hoping to see good really strong growth from chard, etc,  that I will replace it with.  I've also got some tobacco ready to hopefully keep the greenfly numbers down over the winter.  (Though the tobacco may not make it).   I am also converting my friends greenhouse to a similar "easy automatic watering and heat transfer system for the winter.  She is totally impressed with my lazy approach to greenhouse gardening!   .  
Photos (If I uploaded successfully) show what is in the greenhouse.   Thanks,  Brian

Little experimental greenhouse update! Tomatoes, etc.  are gone and I have put in Chard and welsh onions for winter greens.  Still have peppers to harvest.  I am experimenting with the airlift watering system to catalogue it and to make it better and more consistent.  Anyway,  the watering speed  is about 7 liters per hour 2 gallons per hour in the lower planter and about 1 gallon per hour in the upper planter.  Note...   I have the air pump on a timer (which has 15 minute adjustments) so I can set it to be off most of the time.  
I'm sure many of you think I am watering way too much for winter?     But part of the reason is that when water lands on the soil surface, it takes some heat from there and transports it a few cm deeper into the soil.    So the watering is providing heat (and oxygen) transfer to the roots as well as nutrients and water itself!  We are currently at 8 to 10 C outside while it goes up to 16 or 18 in the greenhouse when the sun shines so I think the amount of heat we store under the soil is not trivial.