How difficult is it to regulate a GH? - Orchid Board

Paul Mc · #1 04-03-2011, 08:06 AM

Ok, so I'll admit that I haven't spent much time researching this subject yet.

My partner and I are considering adding a greenhouse to the backside of our house. It would probably only be 6 feet wide by 10 feet deep or so.

I recently saw a thread about greenhouses available from Santa Barbara (I think that was the company), and we're considering either buying theirs or having our own built.

If we buy, I assume we will still have to monitor and regulate the GH throughought the year and this wouldn't be any different than if we had someone build it from local supplies here. So how difficult is it to get the temp and the RH regulated?

I'm also assuming that this would be a non-stop process for a year or so until we get used to what needs to be done in the GH each season (i.e. open vents, heaters on/off, fans on/off, shading clothe if needed, etc...).

RosieC · #2 04-03-2011, 08:50 AM

I have a 6" x 6" and pretty soon realised that an esential thing to add was an auto opener for the single window. Before that I had to remember every warm day to go an open it and I would be at work worrying if the day got warmer than I had expected.

The auto opener was only about £20 for mine and it was WELL worth that. With the auto opener on the window I will still open the door on warm days, but if I forget I don't worry because I know the window will open by it's self and it won't bake inside.

I have a small thermostated heater for the winter which seem to do the job... but them I'm trying to keep it arround 5C min in winter so don't need much.

RosieC · #3 04-03-2011, 09:09 AM

RH is not so easy. You might want to look into a Mistking system from Marty to allow you to truely regulate it.

I currently do a more manual thing of throwing a bucket of water over the floor on dry mornings. It's not really a reliable method though. I plan to get a Mistking system in the long run but I've got to get my tables properly sorted first.

BikerDoc5968 · #4 04-03-2011, 10:22 AM

I think we'd have to know a location; sun exposure, city/state would be helpful. Keep in mind all of the "other" stuff you will need in the greenhouse like water, electricity (110/220), natural gas, etc. I have built from scratch using treated lumber and doorwall glass and purchased a kit that I assembled myself. Certainly the former took longer but was significantly nicer. A lot of this has to do with, "Do you have two left thumbs" and how much time can you devote to the construction/project. The former unit was 16' x 20' and took the better part of a summer with me working at my occupation full time. The kit took all of a weekend, once I completed the base for my specific application, which I constructed myself and I have two left thumbs! I purchased a SunGlo unit through Costco (Costco - Your search for "greenhouse" produced 13 results.) but the same unit can be bought directly from SunGlo. My kit included heater, fans, etc.

As for humidity, well, that is a bit of a problem for me... don't understand why it should be but it is. Temperature is pretty easy; I try to set things for an "average" temperature and things just work out here in Michigan.

For me, my greenhouse gives me hours and hours of pleasure even though there is some work involved; it is just a great experience! One MAJOR consideration as others who have greenhouses will say is that SIZE does matter!!!! Build or purchase something that is as large as your budget and space will allow because in a short time it will be filled and well, I think you see where this is going!

Paul Mc · #5 04-03-2011, 12:11 PM

Thanks guys. After having done some more reading, I am certainly considering buying one that already has the pieces together, as long as it will fit height wise. I've already got the space mapped out for max size.

While I would love to use thick tempered glass for this so you can see the orchids growing inside, I would presume that double panes would be necessary for better temp regulation. I don't like the looks of the anything that "blocks your view."

Rosie, I had not considered having automatic airflow shutters, but that's a great idea. I live in St. Louis, Missouri, USA, and it can get very cold to very hot here in a blink of an eye.

I am planning on including an exhaust fan, thermostat and hygrometer readers/controllers, a heavy duty electric heater, solar roof vent opener(s) (automatic shutters only), an automated mist system (as per Rosie's suggestion), and a sunscreen shade cloth, and probably a regular large fan somewhere set on a timer for semi-continuous air flow.

The position will be against my house in the backyard, with southern exposure. There is only one tree anywhere around and it's canopy will somewhat protect the GH during the noon hours. However, morning and evening it will not, thus the sunscreen shade cloth.

We would also have dedicated electrical lines run to it for operating all electrical stuff, plus a few extra outlets for lighting and whatever else we would want to operate in there. We would also probably have two separate water lines brought out, one for the misting system (though I'm not sure how they work yet so this might not be needed) and another for regular watering/cleaning usage.

BTW BikerDoc, I love your greenhouse! I'm green with envy, lol...

I will look at Costco.

What are shipping costs like for these kits though? Wouldn't it be cheaper to higher a contractor who does greenhouses to make one specific to my specifications? Just a thought.

BikerDoc5968 · #6 04-03-2011, 12:37 PM

The kit I purchased from Costco (SunGlo) was a 8' x 12.5'. It was on sale so I added an additional 30" purchased direct from Sunglo to make mine 8' x 15'. The kit came with a 15000Btu electric heater, and all of the stuff pictured above, an exhaust fan on a thermostat, benches and grow lights. I don't use the grow lights and traded them out for suspended lights so I can see at night in the greenhouse. Since natural gas is significantly cheaper than electricity, I purchased a 20000Btu NG space heater (Home Depot) with built-in fan and use the electric heater as backup.

This kit is extremely easy to assemble. Hiring a contractor with permits etc will be very costly on top of materials. I built a simple frame that extended to a height to meet my existing deck. I used six 2 x 6 posts for the corners and center. Then used 2 x 8 on the exterior and filled the 3 1/2" space with Dow Styrofoam and covered with another 2 x 8 interior. The floor has 3" of Styrofoam under the wood flooring. This all gave me about 10" additional height, which for this greenhouse is great because the peak is only 7 1/2'. I ran 1/2" flex copper in PVC tubing from my home to the greenhouse for NG supply and a 220 electric line to the junction box inside the greenhouse. Because my greenhouse doesn't adjoin my home, I couldn't run a water line into the greenhouse. I use a 3 gal sprayer for watering in the winter and a hose for spring/summer. My kit doesn't come with top/roof vents because of its style. All of this is very simple to do and no permits required as long as your neighbor doesn't rat you out!!!!!

dounoharm · #7 04-03-2011, 02:42 PM

first off and most important in regulating a gh is a MIN/MAX THERMOMETER! get everything assembled and run that thermometer for a few days before putting plants inside....it will tell you the range of temps you have to deal with and you can adjust your fans, exhaust and mist to suit the orchids without endangering them....as for misting, there are many ways to consider....i use a jaybird aquafog 700 mist machine, i had troubles with a mist system over the orchids, it continually dripped unwanted water on the orchids....i couldnt get it right....i have the standard black shadecloth, but i want to invest in a aluminet one for my next major purchase...in the colder months, i use a pool cover, which is like big bubble wrap, to help with the heat loss...it really does help, even tho i only cover the top of the gh with it....there will be 'micro climates' in the gh, you will have to discover where the hot points are, and the cooler spots, to decide how to place the orchids...i dont like orchids on the floor of my gh, they are at risk to slugs and other bugs on the floors...so i put other plants down there, like the amazon lily or ferns....the under bench plants help with humidity also....hope this helps you, and let us know how you are progressing! gl!

DavidCampen · #8 04-05-2011, 12:41 PM

I would suggest that you would want to consider double or triple wall polycarbonate for its insulation value even though it is not transparent like glass. Double wall glass will be heavy and expensive while single wall glass will loose heat rapidly when it is cold outside (and you will get lots of condensation). I am using 16 mm (5/8 inch) triple wall polycarbonate even here in Southern California.

Quote:

Originally Posted by Paul Mc

...
While I would love to use thick tempered glass for this so you can see the orchids growing inside, I would presume that double panes would be necessary for better temp regulation. I don't like the looks of the anything that "blocks your view."

Rosie, I had not considered having automatic airflow shutters, but that's a great idea. I live in St. Louis, Missouri, USA, and it can get very cold to very hot here in a blink of an eye.

I am planning on including an exhaust fan, thermostat and hygrometer readers/controllers, a heavy duty electric heater, solar roof vent opener(s) (automatic shutters only), an automated mist system (as per Rosie's suggestion), and a sunscreen shade cloth, and probably a regular large fan somewhere set on a timer for semi-continuous air flow.
...

RosieC · #9 04-05-2011, 02:59 PM

Quote:

Originally Posted by DavidCampen

I would suggest that you would want to consider double or triple wall polycarbonate for its insulation value even though it is not transparent like glass. Double wall glass will be heavy and expensive while single wall glass will loose heat rapidly when it is cold outside (and you will get lots of condensation). I am using 16 mm (5/8 inch) triple wall polycarbonate even here in Southern California.

I agree. I have a double wall polycarbonate. Light is more difuse than with glass... but that's good for most orchids

I still get plenty of light in and have to put up a sade cloth in summer. I did line it with bubble wrap as well over the winter but it didn't need that until the really cold weather and I've removed it again now.

pedidiva · #10 04-28-2011, 12:54 PM

for me the heating/cooling was difficult. Got an evap AC (works here as we're semi arid) & electric heaters. Found a misting fan that works quite well to keep huminity up.