Greenhouse Recuirements for Orchids

[orchidsamore]

OK I am a commercial nursery with $250,000 in inventory so I put my money where my mouth is.

I grow everything outside with no plastic and no heat. Average temperatures are the same as yours and temps range from 34-to over 100. I do nothing to control these temps.

I monitor temps on an hourly basis (there are many weather apps for smartphones and computers) . Lows are usually only 1-2 hours. I also use a high low thermometer for reference of the extremes.

I grow a much wider variety of orchids than anything mentioned here as well as all the varieties named so far. All are grown next to each other in the same greenhouses.

Cool growing plants can be an issue. I do not grow a great quantity of them. Orchids are tough and will adapt to conditions they not prefer. I grew Miltonia (cool growing) at temps up to 100 this summer and loss a very low percentage. Not something I would recommend but an example of what is possible.

Additionally in Southwest Florida it rains 2 hours a day every day from April to October. All of this goes directly onto the plants.

My main greenhouse I have Vanda, Mrymechophia (higher light than Vanda they prefer unfiltered sun all day) low light Vanilla bean, Pleurothallis, Angraecum , Eria, Lycasta, Catasetum (which get water year round), Zygopedilum and on and on. Nothing gets special care. This house gets water an hour a day every day in the winter.

Your low of 6 degrees surprise me with your averages. If I fear freezing temps I just turn on the sprinkler system all night and shut it in the morning. No different than if it rained all night. I do not know if that is practical for you.

I erected a 34x72 foot greenhouse a couple of years ago. It is a 4x4 wood frame I constructed myself with metal arches I bought as scrap metal. With ground cloth, shade cloth. irrigation sprinklers, and fertilizer injection the total cost was only $3000.

From a commercial contractor this would have been $10-18,000. Your cost will depend on how much you want to contract out.

[katrina]

Jerry - you can't possibly give recommendations based on average temps...especially when you don't know where the OP lives. You should know this.

For example...I'm in Columbus, Ohio and if I look at only the AVERAGE temps...it does not tell the whole story.
Columbus -
Month Low High
Jan 20.3°F 36.2°F
Feb 23.5°F 40.5°F
Mar 32.2°F 51.7°F
Apr 41.2°F 62.9°F
May 51.8°F 73.3°F
Jun 60.7°F 81.6°F
Jul 64.9°F 85.3°F
Aug 63.2°F 83.8°F
Sept 55.9°F 77.1°F
Oct 44.0°F 65.4°F
Nov 34.9°F 52.4°F
Dec 25.9°F 41.0°F

This morning it is currently 23 outside my house and has been that temp for at least 10 hours. Last week we had temps down into the single digits (w/wind chills into the negative)...for days. You don't see those temps in the December averages listed and I don't know of any tropical orchid that could've survived my temps last week. In the summer, we have many days that go well above 90 degrees and we have some nights in early summer that can dip down into the upper 40's.

Average temps are basically worthless for a project as involved, and possibly costly, as a greenhouse. And to use them as a guide for this sort of build could be the death of many orchids. As already mentioned, one needs to know the absolute lows/highs and how long (hours, days) those low/high temps would be experienced over any given period of time.

[Dollythehun]

Amen, Katrina. Midwest weather is a different breed of cat.

[NeonKraken]

I'm willing to downsize my gh if it means lower costs. 12'x20' s probably the maximum I would go, as it takes up a big chunk from my backyard. I'm not to concerned on the material costs, as I can probably find/buy most of it as scrap. My main concern cost wise is heating/cooling systems and pluming. One of the main reasons I want to build a gh is for watering purposes, so the plants will already be outside. For example, when I water my mounted Oncidium Sphacelatum which I water almost everyday, I have to take it outside to use the hose water, then bring it back in, and put a big trash bag under it so it doesn't drip on my wooden floor. Obviously I don't mind this too much, but it would be easier if I had even a small gh. If I need to take a few of my orchids in a couple months out of each year, I'm fine with that. Thank you everyone so much for your time.

[katrina]

Originally Posted by Dollythehun

Amen, Katrina. Midwest weather is a different breed of cat.

Don't we know!

[NeonKraken]

Would anyone happen to know a good place to find some ideas for a plan?

[Roberta]

Check out this organization. You may get some ideas.
https://www.hobbygreenhouse.org/

And as several others have pointed out, average temperatures are meaningless. You have to plan for the "corner cases" the extremes, both hot and cold.

[Dollythehun]

If I had it to do over, I would talk to growers and hobbiests in my area and pick their brains. They will be glad to help.

Also, try a bootbtray or puppy pad under your Oncidium.

[NeonKraken]

Alright. Thanks everyone. From what I've gathered, It seems like I will need a cooling and heating system. I will talk to local growers and see what they suggest. Thanks. Are there any structural requirements or materials I can and can't use?

[Dollythehun]

How much do you want to spend? Modine heaters are one of the best, but you can buy a decent garage heater at Menards for under $400.00. You can skin it with poly carbonate or double skin with uv poly. In the later case you will need an inflator kit. You'll need an offset thermostat too. A smart grower would have a back up heater and an alarm system. Benches can be made from snow fence and concrete blocks or you can pop for rolling benches...You get the drift. Take a look at the Growers Supply website to get some pricing ideas or follow the link Roberta gave you.