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Author Topic: new greenhouse planning  (Read 18495 times)

BajaJohn

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Re: new greenhouse planning
« Reply #150 on: November 06, 2017, 06:37:07 AM »
You can reduce moisture problems by using closed cell foams which are a natural vapor barrier.......
https://buildingscience.com/documents/reports/rr-0912-spray-polyurethane-foam-need-for-vapor-retarders-in-above-grade-walls/view
Many solid and spray/pour insulating foams are not closed cell and therefore allow diffusion of water vapor where it condenses on the cold side so be sure you use a foam that has vapor barrier properties. Apparently mealworms will eat polystyrene foam although it may not be their first choice in a greenhouse.
« Last Edit: November 06, 2017, 06:40:06 AM by BajaJohn »

brian

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Re: new greenhouse planning
« Reply #151 on: November 06, 2017, 12:36:41 PM »
Millet, good to hear you aren't getting mold.  Am I correct in assuming you have a gap between the glazing and the foam board where the frame itself resides?  I worry that moisture would work into this gap and grow mold as there would be no airflow.  Given that you aren't seeing that problem, maybe my fear is overblown.  Perhaps the sunlight betweent the glazing and the foam is keeping mold from growing?  Or, perhaps you've sealed it so well that moisture simply isn't reaching that area.

BadFish and BajaJohn, spray foam is an interesting idea.  I use the canned foam to seal cracks, and it works well despite being an awful sticky mess.  It solves the problem of getting the insulation attached directly to the glazing/frame with little possibility for moisture penetration.  From reading that document you linked to it sounds like using PU foam without an extra vapor barrier is likely fine, as there is nothing that can rot in my greenhouse structure.  I'm not so concerned about it being perfectly flat... my biggest concern is that it's very permanent.  It would be nearly impossible to remove the foam from the frame if I ever need to disassemble any part of the wall frame.  I'm not sure why I would... but it worries me a bit. 

Millet

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Re: new greenhouse planning
« Reply #152 on: November 06, 2017, 03:19:33 PM »
brian, no there is no space between my insulation boards and the glazing.  The insulation boards are attached directly to the north wall glazing.  I sealed the instillation board seams with the silver sided tape.
« Last Edit: November 06, 2017, 03:21:23 PM by Millet »

brian

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Re: new greenhouse planning
« Reply #153 on: November 06, 2017, 03:59:09 PM »
brian, no there is no space between my insulation boards and the glazing.  The insulation boards are attached directly to the north wall glazing.  I sealed the instillation board seams with the silver sided tape.

How is this?  Doesn't the frame get in the way?  Or are your insulation boards fitted around the frame members?  For example, in the photo of my north wall, you can see metal framing that the glazing attaches to.   If I fitted the insulation flush with the glazing it would require cutting foam boards to exactly fit between the frame members.

Millet

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Re: new greenhouse planning
« Reply #154 on: November 07, 2017, 12:20:52 AM »
Yes, I cut the insulation boards to fit exactly in between the frames.  In fact I cut all boards 1/4" longer and wider than the frames, and squeezed them in for a very tight fit.  Being a polyurethane foam product they squeeze down nice and tight, plus I used glue..  Actually polyurethane boards are really very easy to cut.  I use a yard stick and a simple sharp kitchen knife. I did much the same for the back wall, which I put up each night during the winter, and remove each sunny  morning. Doing so greatly helps with the heat bill, which can be high in Colorado.
« Last Edit: November 07, 2017, 12:27:49 AM by Millet »

brian

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Re: new greenhouse planning
« Reply #155 on: November 07, 2017, 09:21:59 AM »
Ah, thanks for clarifying.  Yes, with boards flush against the glazing I wouldn't expect any mold to grow.   

brian

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Re: new greenhouse planning
« Reply #156 on: December 06, 2017, 02:25:44 PM »
...
Also, a VERY important consideration - you must provide for easy access for pollinators in the spring.  I have hundreds of different species of bees, wasps, moths, butterflies and flies pollinators every spring.  They get confused by any covering that restricts UV....can't find their way out.
...

So what is your solution to this problem?  Leave the doors wide open in spring?  That's pretty much my only option.  I have big double-doors so I would hope this is enough.  The glazing is UV coated of course so I'm not sure how to avoid the issue you describe.

Millet

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Re: new greenhouse planning
« Reply #157 on: December 06, 2017, 03:13:56 PM »
Many plants need polinators, but of course Citrus trees do not---neither does tomatoes nor pineapples as they are self polinating.

Mark in Texas

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Re: new greenhouse planning
« Reply #158 on: December 08, 2017, 09:57:08 AM »
So what is your solution to this problem?  Leave the doors wide open in spring?  That's pretty much my only option.  I have big double-doors so I would hope this is enough.  The glazing is UV coated of course so I'm not sure how to avoid the issue you describe.

The design.

I think you'll be OK.  If you have wide doors they'll find their way in and out.  Getting out is a bit tough as they use UV light to hone in on.  I assume they're attracted to flower aromas.



Mark in Texas

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Re: new greenhouse planning
« Reply #159 on: December 08, 2017, 09:59:57 AM »
Many plants need polinators, but of course Citrus trees do not---neither does tomatoes nor pineapples as they are self polinating.

You mean you're not in there vibrating your maters with a cordless toothbrush?   ;D

I have a lot of pineapples, some of the newer ones like the white boyz, others like store bought "twistees".  Just got a bottle of lab grade calcium carbide to play with this spring.  Got some White Jade getting up to 5' across.

Millet

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Re: new greenhouse planning
« Reply #160 on: March 16, 2018, 10:08:55 PM »
Brian, how about a new picture update of your new greenhouse?

brian

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Re: new greenhouse planning
« Reply #161 on: March 18, 2018, 04:02:34 PM »
The exterior still looks identical, but I guess I hadn't posted any pictures from inside yet!   In truth I haven't done much since the last update aside from add some bits of insulation that aren't really visible, and I've mostly levelled out the dirt inside.   I also painted the inside foundation walls white.





dirt inside is now level, even though grade slopes around it


I still don't have proper heat or electric.  My HVAC contractor cancelled right before I left for a trip to India for a month.  I ended up putting all my trees in my basement the entire time, in darkness at around 50F temp.  However, they did just fine and I put them right back in the greenhouse when I came home.  I've been running propane space heaters when it gets below freezing, with circulating fans on an extension cord  :-\ 

It's just warming up enough now to get back on the utilities so I can finally be complete.   I have some ceiling-mounted circulator fans to install, also.  Then, the next thing to worry about is cooling.   I'm keeping all my trees in containers until I've made it through the peak of summer, just in case temperatures get out of hand.   

Last week I sprayed a surfactant on the inside walls of the polycarbonate glazing.  The product is supposed to eliminate condensation, but it did not work at all for me when I applied at the recommended rate.  The condensation came right back.  I am going to try doing it again with double the concentation before I give up and go with another product. 

Some of my trees had been struggling from the frequent near-freezing temperatures, and a handful that I severely under-watered had almost completely defoliated.   However, everything seems to be bouncing back.  Bare areas are all flushing like this:



Once the final heat and electric hookups are done I will looking into an automatic watering system, and likely some kind of active cooling such as a fogging system or swamp cooler.  I have public water and it doesn't seem to be hard like the well water at my old house.  I believe I can use foggers here without scale buildup. 

I have two sets of temperature sensors.  One is internet-connected and I can pull up the temperature from a phone app, and it can send text message alerts if temps get out of range.  The other is a simple radio sensor that runs entirely on batteries and has an audible alarm.  This way if I lose power, or if batteries die, I still have a backup alarm in case it gets too cold or my portable heater runs out of fuel. 

(the temp is really high on the sensors in direct sunlight, but the others show accurate air temps)



Because I'm running unvented propane heaters right now, and because I don't have enough heat to allow me to do much ventilation outside the warmest hours, I have a lot more humidity than I'd like.  I expect once I have the final utilities in place it will be more controllable. 

I haven't yet insulated the north wall.  I will probably save that for next winter.  I happend to find some cheap Ikea hanging containers (meant for some kitchen use) that work perfectly for hanging seedlings along the greenhouse structural rails.  I put all my trifoliate seedlings there, and beacuse they don't take up any floor space I am planning to grow many more for future grafting. 

Finally, I am thinking about putting white landscaping fabric down on the greenhouse floor to make it even brighter inside.  Right now my floor is just clay dirt which turns into mud when wet and so would the fabric brown.  However, I am thinking if I put a layer of much down first and put the white fabric on top the mulch won't stain the fabric and it should work pretty well if I sweep up fallen leaves occasionally.

Millet

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Re: new greenhouse planning
« Reply #162 on: March 18, 2018, 04:26:42 PM »
Brian, nice greenhouse.  When you have your main heater hooked up, you might not want it hoked directly into your electric source.  I have two 250,000 BTU over head heaters set to come on at different temperatures so that if one stops working the second one can take over until repairs are made.  When the greenhouse was built I told the electrilon to make one of the heaters with a two prong plug end,  that way if I lose power during a winter storm I can plug it directly into a generator.    Be sure to have the intake vents set up so that they open every time the exhaust fans turn on, and close when the fans shut off.  You did a magnificent job with your greenhouse, i really looks to notch.  I'm sending your tree on Monday March 19. 
« Last Edit: March 22, 2018, 11:32:05 AM by Millet »

Tom

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Re: new greenhouse planning
« Reply #163 on: March 18, 2018, 05:15:33 PM »
Brian, Everything looks fantastic ! Thanks for the update. Your dirty foot made me think of Adam Sandler in Mr. Deeds. Sandler had a black foot that had zero feeling and he played a prank on his butler. Also the butler was ridiculously quick and when asked about it he always replied do not underestimate my sneaky ness . There were other ongoing gags and I guess its my favorite Sandler movie ! Tom

cory

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Re: new greenhouse planning
« Reply #164 on: March 18, 2018, 07:42:39 PM »
Brian, your greenhouse looks great!  Thanks for providing the update.

Cory

Mark in Texas

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Re: new greenhouse planning
« Reply #165 on: March 19, 2018, 07:48:13 AM »
Yep, looks top notch!  Highly recommend a couple of these.  I went with non-vented for orchids, no fresh air intake provisional.  The thermostats are very accurate.   Worked great.

http://southernburner.com/

Daintree

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Re: new greenhouse planning
« Reply #166 on: March 19, 2018, 09:43:12 AM »
AWESOME greenhouse!  The size is fantastic!
Yeah, I love my Acu-Rite temp sensors, but have the same problem of trying to find a place in the greenhouse where the sun never hits it. Finally I just gave up.  After all these years, I know it never gets too HOT in there because the fan kicks on, and we don't have power outage problems.  My only worry is it getting too cold in winter. I have the low-temp alarm set, but not the high-temp.

brian

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Re: new greenhouse planning
« Reply #167 on: March 21, 2018, 07:11:07 PM »
Quote
..When the greenhouse was built I told the election to make one of the heaters with a two prong plug end,  that way if I lose power during a winter storm I can plug it directly into a generator.    Be sure to have the intake vents set up so that they open every time the exhaust fans turn on, and close when the fans shut off.  ..


This is a very good idea.  I was thinking I may be able to use a battery backup instead of a generator as I don't think too much electricity is needed to power the fans and heaters.  I'll have to do a cost comparison, I don't know much about backup power options.   As for the vents, I noticed that unless I pin them closed even a breeze will open them up, so I am reasonably confident that the suction from the large fans will open then, and if it does not I will find a powered solution. 

Quote
...Yeah, I love my Acu-Rite temp sensors, but have the same problem of trying to find a place in the greenhouse where the sun never hits it. Finally I just gave up...


I have enough sensors scattered around that I assume the coolest ones are correct when its sunny.  So if I see 85F/95F/100F its probably around 85F air temps.  I have a digital meat thermometer I use to check container temps to make sure the sun isn't overheating them and so far things have been ok.  I will rotate the white-painted side to point south as it gets warmer outside, and once they are in the ground it won't be a concern anymore.

Quote
Mark - http://southernburner.com/


I wish I had done more research before I purchased my heaters.  I would probably have gone with something different, but I will make do with these for now.  I see the Southern Burner heaters you linked to must be using an electrocouple thermocouple to ignite.  My gas water heater has the same setup, and I thought it was pretty neat that it doesn't require any power.  This would definitely be a better solution, but its too late for me to exchange my heaters.


Quote
Your dirty foot made me think of Adam Sandler in Mr. Deeds. Sandler had a black foot that had zero feeling and he played a prank on his butler. Also the butler was ridiculously quick and when asked about it he always replied do not underestimate my sneaky ness . There were other ongoing gags and I guess its my favorite Sandler movie ! Tom


 :D     I remember that one


Thanks for the kind words, all.
« Last Edit: March 23, 2018, 03:32:16 PM by brian »

Mark in Texas

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Re: new greenhouse planning
« Reply #168 on: March 22, 2018, 07:36:07 AM »
Southern Heater has a thermocouple you hang anywhere for convenience.  Copper "cord" is probably about 5' long.  Been 20 years but remember it having a pilot flame that's always lit for ignition.

brian

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Re: new greenhouse planning
« Reply #169 on: April 14, 2018, 04:20:14 PM »
I now have electricity in my greenhouse.  Today is 83F with full sun.  My greenhouse temperature sensors are reading 93F when NOT in direct sunlight, and around 105F in direct sunlight (which doesn't mean much).  This is with vents open and exhaust fans running.  I believe I will need to implement some kind of cooling solution, and/or use shade cloth.  As an experiment I am going to spray a light coat of water all around to see how strong the evaporative effect is.  Weather report says it is 31% humidity outside

Millet

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Re: new greenhouse planning
« Reply #170 on: April 14, 2018, 04:45:16 PM »
Before I put a wet wall cooling system in my greenhouse, I used a shade cloth to help cool the greenhouse.  In fact iI tried several types of shade cloths, the one that worked the best is called Aluminet . You can find Aluminrt shade cloth on the Internet. Citrus grows best between 70 & 90-F.  At and above 95-F growth stops  and greatly slows down above 90-F.
« Last Edit: April 14, 2018, 04:57:25 PM by Millet »

brian

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Re: new greenhouse planning
« Reply #171 on: April 14, 2018, 04:52:07 PM »
Thanks Millet.  I am not sure which I will do first.  I think it depends how quickly I can get a fogging system set up before really hot days come.

After I sprayed a light coat of water around the greenhouse the temperature dropped 10F all around.  Not bad!

Millet

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Re: new greenhouse planning
« Reply #172 on: April 14, 2018, 05:01:49 PM »
I also used the water spray to lower the temps .Brian, check the GH temperature again in 15 minutes & you will find the temperature right back up. 

brian

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Re: new greenhouse planning
« Reply #173 on: April 14, 2018, 06:04:03 PM »
It stayed cool for a bit but the water hasn't evaporated fully.  I hope with a fogging system it could do a regular spray.

brian

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Re: new greenhouse planning
« Reply #174 on: April 14, 2018, 10:55:29 PM »
I looked a bit more into the battery versus generator power backup options.   From my brief research battery backups are pathetically inferior to generators.   I am somewhat surprised, given that batteries are powering cars these days.

"Most home batteries kick out between 3 to 9 kilowatts of power, and costs range from $4000 to $10,000, depending on the features youre looking for in a home battery. "

Two 1/2hp exhaust fans use about 1.5kw/hr alone.   So the cheapest battery backup could only keep cooling fans running for... two hours?  For $4k?   

I liked the idea of avoiding the noise, size, maintenance of engines versus batteries but wow batteries really can't keep up for any reasonable cost.

 

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