Upcoming Arctic blast and Greenhouses

[Mark in Texas]

Many years ago I built a south facing lean-to greenhouse for growing orchids while living in my Gulf Coast home near the bay and made the BIG mistake of painting the pine with a few coats of a copper cuprenate preservative because I was too cheap to go the extra mile and use pressure treated lumber, which now really doesn't cost much more..  The paint was supposed to be the  "silver bullet" for rot prevention.  Wrong.    Within 5 years you'll be replacing your painted lumber with ground contact pressure treated lumber which is a PITA.  You'll be removing all the covering etc. etc.   

I use Palram Dynaglas SolarSoft on a large greenhouse with 10' walls and a 18' ridge.  It is the best high light, light diffusing corrugated polycarbonate available.....with UV resins extruded into the outside surface and condensation preventive resins extruded into the inside.

Nice job, and good luck!

[KarenRei]

Thanks mark, I can't stress that enough. Never underestimate the ability of a greenhouse to rot or rust its support structures! 

[TriangleJohn]

I think you'd be better off building some sort of patio structure that you temporarily cover with greenhouse plastic film during the really cold part of winter. Make it a pergola or arbor or just two arbors ten feet apart, however big you need for the plants you intend to grow. Keep the plants in pots and move them around the yard during the summer while you use the structure for human comfort (shade), then shove everybody in for the winter and cover it.

Even though simple 6mil plastic sheeting isn't perfect - you will be amazed at what a difference it makes when you're desperate. I've had my heaters fail in the middle of the night and the temps drop into the 20's and still barely lost anything. I think it is because the "shelter" under the sheeting slows down the decent in temperature.

I went with a hoop house or high tunnel that I continue to modify (they aren't meant to be used as sealed up greenhouses). The high center ridge helps deal with excess heat on a sunny day. Even on cold nights without any sort of heating in use it tends to stay above freezing.

[Californiatropicals]

Soil inside the greenhouse will be roughly the temperature of the air in the greenhouse. Soil outside will be the temp of soil outside. Soil in-between will be relative to how close it is to the inside and outside. If you want to extend the warm-soil area, you can add underground panel insulation, it works well (best is to slope it out and away from greenhouse to maximize your soil space). I did this even though I wasn't planting things directly in the ground, simply to maximize the ground's heat storage potential. Underground insulation doesn't need to be as perfectly sealed as above-ground, since there's no air convection.

You're only looking to raise temps by maybe 10C in the winter? Hmm, you may want to avoid the bubble wrap and let your plants have the extra winter light instead. Just a thought.  It does have an affect on light transmission. And of course make sure you're very well vented come summer!! I should reiterate that I strongly recommend automatic venting. Greenhouses can change in temperature very rapidly between when the sun isn't out and when it is, and especially in spring, this can mean rapid fluctuations between too cold and too hot. And I doubt you intend to sign up for a new job, that of "greenhouse temperature monitor / vent operator" 

Oh I see your point, I think I forgot to mention that I intended to take off most if not all of the plastic or clear paneling during the warm months. I'd never considered soil heaters, but according you, oscar  and mark it might be a good idea... Something I will have to look into. -- I could never get jackfruit seedlings to grow here they languish outside and probably for having cold soil.

[MangoFang]

OH, and Cal Tropicals - or anyone - DO buy soiling heating cables (if you decide to use them) with a thermostat so you can control the temps.  I stuck a couple of the cheap ones I bought in the soil around some papayas one winter, forgot about them and in the spring the roots just cooked to death as the ground heated up naturally, the additional heat from the cables made it unbearable...

Marklee - yeah that is one pretty structure - nice job...

And good luck to all......Gary

[Californiatropicals]

OH, and Cal Tropicals - or anyone - DO buy soiling heating cables (if you decide to use them) with a thermostat so you can control the temps.  I stuck a couple of the cheap ones I bought in the soil around some papayas one winter, forgot about them and in the spring the roots just cooked to death as the ground heated up naturally, the additional heat from the cables made it unbearable...

Marklee - yeah that is one pretty structure - nice job...

And good luck to all......Gary

Gary

Are they expensive to  run? I really like the idea of using it for papayas, I love papaya, and we seldom get frost that would kill the top, however the cold soil kills the roots and they topple by january..   I am definitely going to look into them for papaya, Papaya is so expensive at the store!

[KarenRei]

OH, and Cal Tropicals - or anyone - DO buy soiling heating cables (if you decide to use them) with a thermostat so you can control the temps.  I stuck a couple of the cheap ones I bought in the soil around some papayas one winter, forgot about them and in the spring the roots just cooked to death as the ground heated up naturally, the additional heat from the cables made it unbearable...

Marklee - yeah that is one pretty structure - nice job...

And good luck to all......Gary

Gary

Are they expensive to  run? I really like the idea of using it for papayas, I love papaya, and we seldom get frost that would kill the top, however the cold soil kills the roots and they topple by january..   I am definitely going to look into them for papaya, Papaya is so expensive at the store!

LOL, if you're looking to save money, greenhouses are not for you! Now if you're looking for a new money pit...

[marklee]

Just finished the green house a few days ago. It's been so hot that I put up shade cloth and ran a fan in the day. The next step is to line the inside with bubble wrap, dig a few holes and install the heater cables. The height is 10 feet so I should be able to get some decent size on the trees I decide to grow inside.
Does anyone have any ideas what to try? I'll probably try to keep the inside at 50 to 55 degrees. And 70% humidity and above.

[Luisport]

Ryan Maue ‏@RyanMaue  2 h 
Avg CONUS temp at 12z Jan 7 from GFS forecast is 9.8°F ... sub 10°F CONUS avg temps represent heavy duty Arctic cold. pic.twitter.com/aGtNj2Hoiv

[Luisport]

Business Insider ‏@businessinsider  2 min 
There Are Some Insanely Cold Temperatures In Parts Of America Right Now http://read.bi/KkwHFl

[KarenRei]

Wow, it's going to be colder in Corpus Christi than in Reykjavík. And -40F in Minneapolis? When it gets down to -40, it doesn't matter any more whether you list it in Fahrenheit or Celsius!

[nullzero]

Wow, it's going to be colder in Corpus Christi than in Reykjavík. And -40F in Minneapolis? When it gets down to -40, it doesn't matter any more whether you list it in Fahrenheit or Celsius!

This is why I could never live in anywhere but a solid 9a or higher. It should help a lot with the water moderation factor with keeping Iceland warmer in the winter.

[KarenRei]

Wow, it's going to be colder in Corpus Christi than in Reykjavík. And -40F in Minneapolis? When it gets down to -40, it doesn't matter any more whether you list it in Fahrenheit or Celsius!

This is why I could never live in anywhere but a solid 9a or higher. It should help a lot with the water moderation factor with keeping Iceland warmer in the winter.

Yeah, our climate is basically, "take a typical temperate US location, now completely remove summer, then stretch out all the remaining seasons to fill the gap... and add wind". Not unusually cold, just never hot. But still, I grew up in the US, southeastern Texas specifically. It's just funny to picture that it's going to be freezing where part of my family is in Houston while the ice is melting here near the arctic circle.  I hope my mother has the bananas I gave her inside!

[Luisport]

Looks like the GFS has some what backed off with the coldest air pushing down into Florida. Freezing line was around Tampa and it's backed off to the north on the 12z run. 06z, Jan 7th - freezing line down to Tampa. http://i403.photobucket.com/albums/pp114/SGOS/gfs_namer_114_850_temp_mslp_precip_zps688e4f2b.gif 12z, Jan 7th - same time freezing line is further north. http://i403.photobucket.com/albums/pp114/SGOS/gfs_namer_108_850_temp_mslp_precip_zps6d0b05f8.gif

[mangomaniac2]

In Phoenix, I purchased a king canopy greenhouse in a box. Put it up in about 1/2 hour. Bought a Delonghi rotating heater for Lowes for $40. All my mango trees are flowering big time. Cheap and easy. Spray weekly or bi-weekly with liquicop fungicide. Water only when seeing signs of stress then water thoroughly.

[Californiatropicals]

lol... I have to say, I haven't even yet began putting together a greenhouse yet. It's been such a warm winter here that I am reconsidering if I even needs one, or even if I do, the size it should be. The  last few weeks have been in the mid 60s Christmas day and the last few days have been in the high 60s.. it doesn't feel like winter at all! In my pond, water lilies are already starting to grow I've never seen that this early.  It also looks like a cherry tree wants to bloom.  Strange weather, I hope it keeps up! lol

[Luisport]

US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 02 2014

Excerpt:

TEMPERATURES ARE PREDICTED TO RANGE FROM 12 TO PERHAPS AS MUCH AS 40 DEGREES BELOW NORMAL, WITH THE LARGEST DEPARTURES EXPECTED OVER THE MIDDLE MISSISSIPPI VALLEY AND OHIO VALLEY. THIS MAY BE THE COLDEST AIR MASS TO AFFECT THESE TWO REGIONS IN THE PAST 20 YEARS.

[treefrog]

solar heat.

greenhouses can be partially heated with passive solar.  the idea is that black plastic tanks filled with water are placed in the greenhouse (between the trees, under the shelves/benches - wherever.  they warm up during the day, and slowly give off heat at night.  a backup system kicks in with a thermostat when temps drop to a selected setpoint.  this way, the heating system runs less often and for shorter periods.  cuts waaay down on the power or fuel bills.  reflective surfaces on the inside of the north wall are a nice touch too.

[marklee]

solar heat.

greenhouses can be partially heated with passive solar.  the idea is that black plastic tanks are placed in the greenhouse (between the trees, under the shelves/benches - wherever.  they warm up during the day, and slowly give off heat at night.  a backup system kicks in with a thermostat when temps drpop to a selected setpoint.  this way, the heating system runs less often and for shorter periods.  cuts waaay down on the power or fuel bills.  reflective surfaces on the inside of the north wall are a nice touch too.

Good ideas there, thanks

[Ethan]

Does anyone have any ideas what to try? I'll probably try to keep the inside at 50 to 55 degrees. And 70% humidity and above.

Mangosteen!  I'd love to say Marang or durian but 10' probably isn't enough.  The GH is looking really nice Mark.

CT, glad you haven't needed your greenhouse, yet.  The weather has been really nice but it should cool off again and hopefully dump some snow on the mountains.  We need it, I want to be able to water my plants this summer.

[Luisport]

http://cdn.makeagif.com/media/1-05-2014/AO6qCl.gif

[Luisport]

Polar Vortex Reaches Minnesota (dangerously cold into Tuesday morning - greatest frostbite risk since mid-90s)
Posted by: Paul Douglas Polar Displacement

To be fair, we don't have to worry about hurricanes, earthquakes or volcanoes. But once every decade or two the North Pole shifts south, temporarily, leaving all of us scrambling for cover and a warm, safe place to hibernate for a few days.

All those tales of frigid hardship your grandparents scared you with growing up will come true over the next 36 hours as the "polar vortex" - air that should be over the Arctic Circle - sails over our heads.

Pluto, with lakes.

According to NOAA the mercury has stayed at or below zero for at least four consecutive days on 27 occasions in the Twin Cities from 1873 to 2014. The record? 1 week below zero in 1912.

What makes this cold wave notable and potentially historic is a strong pressure gradient whipping up a stubbornly evil wind of 15-25 mph. With air temperatures near -25F early Monday that will make for an otherworldly wind chill of -55F.

Exposed skin can become frostbitten in 5 minutes.

Closing down Minnesota schools Monday was a good idea. And if your car stalls or breaks down call 911 or AAA. Wait for help to reach you.

We top zero on Wednesday; 30s this weekend will feel toasty. For the record, this is the worst of winter, possibly the coldest air since 1996.

Think warm thoughts. Be careful out there.
http://www.startribune.com/blogs/238741671.html

[Luisport]

AccuWeather.com ‏@breakingweather  30 m 
Current temps. that are colder than the South Pole (-12 F): Fargo, ND (-19 F), Duluth, MN (-19 F) & Glasgow, MT (-17 F).

[Luisport]

NWS Midland
@NWSMidland
Temps 30 degrees colder today than yesterday! Stay warm out there. Very cold temps return for Monday morning. Details to come. #txwx #nmwx

[Sven]

Nice job on the greenhouse Mark!

I’m not sure how much power those soil heaters will draw but I always thought it might be cheaper to use a gas water heater and run water lines through the soil with a small circulation pump.  It should be fairly easy to set up a thermostat/controller similar to water solar panel systems to control the flow through the system based on the temperature of the water coming back out of the soil.  You might have to use copper, which would get expensive, but maybe the thin wall class 200 PVC would transfer heat well enough.  Just another option.

Sven