Generator all the way.
But you need to think ahead and have the plan in place. It's no fun loosing power at 2:00am and then try to figure out how to hook it up.

Set a main breaker between the meter and your junction box. If you loose power flip that breaker off. Then have a quick way to plug your generator in at that point in the circuit. You want to have the main power to your g/h off when you are running your generator. If the power comes on while your generator is hooked up you'll blow the circuit in your generator.

If you insert the power from the generator in the correct point of your main circuit you should be able to run power without having to disconnect any power line in the junction box.

All this assuming you have a meter and 220 running to your g/h. If not then make the necessary adjustments. And above all test and plan when it's warm. opps to late.

I have a 14X 20 and if I lose power, no big deal. I heat with a propane heater that has a standing pilot light...

Thanks Mylu and Weebus,
Is a propane heater like an oil heater? What's a standing pilot light?
Thanks for helping me understand this!

yep,i'm with weebus.when i built the greenhouse,i built it with power outages in mind.we lose power a couple times a winter.ice storms,and a little snow.u can pamper,and baby your plants all winter-then lose power ONE NIGHT in february-and ALL IS LOST.just one night at 25f is all it takes.so my heater is propane,with a standing pilot.i have a 250 gallon propane tank,so one fill up more than covers the whole heating season.just set that thermostat-and forget it.i know many use electricity,but it's too much to deal with.a gas heater seems the only way to go.last year when power went out,we almost camped out in the greenhouse.

A standing pilot light is when the pilot light is always burning and the heater just kicks on and off by itself. (I learned that here)

Mylu, it's a really bad idea to have any possibility of connecting an unsynch generator to the mains. A better approach would be to have a DPDT (or at least a SPDT) centre off switch that selects between mains and generator. Even more clever is to do that with a relay/contactor that switches back to the mains if the mains returns.

What do you do in the case of a gas failure? A few years ago the whole of melbourne was without mains gas due to a large oil company not spending money on maintanance and training. Quite a few companies went bankrupt.

If your greenhouse is your livelihood then use multiple fuels. (If a greenhouse is your livelihood, what are you doing reading the rantings of us amateurs ;)

I'm having a hard time figuring out how to pitch the idea of a generator for the greenhouse to my wife! "Honey, I need to protect the plants...we may be cold for a little while, but the plants are fine! We have lots of blankets!" These things are expensive and probably not cheap to have hooked up properly either. The best way was mentioned above. If power goes out, it immediately kicks off your generator. When power comes back on, there is no way for the power from the generator to go back up the line. I hope to be able to install such a system next year.

OK guys, maybe I don't know enough about generators. Don't you have to start them like a lawn mower with a pull cord? If so, who is going to be standing there to do that when the power goes out?
And what if your generator is not powered to run everything in the GH? Let's say I have a 2000W generator (el cheapo version at ACE is $200). I have 100amp service to the GH so I can use my 400W MH lights. I use propane for heat, so I really just need to power the controller and some fans if the power goes out. If the generator were to kick on automatically, it wouldn't be able to handle the load of all the lights, fans and controllers.

Wouldn't it be better in this case to leave the lights off for a couple of days and just plug in the fans and controllers to the generator? SB

Newer generators can be fueled by many types of fuels and will automatically kick on when power goes out. Obviously they would be more expensive and would require professional knowledge to have hooked up. Worth it? I think piece of mind and the investment we have inside the greenhouse would be worth it if you were to lose power while you were away. You could get a size for whatever needs you choose. Heating would be the main priority of course followed by fans or whatever else you feel is important. I personally wouldn't worry about lights. The plants would not suffer for lack of sun/lights for a few days. Keep in mind that the more Kilowatts the generator is rated, the cost goes up a lot. You could always price one out where you could also hook up some household items as well...heating, fridge/freezer, some lights. These can cost upwards to $5000, if not more...not to mention installing. I believe this may be the only way I'm going to be able to justify this at all. I'd hate to put up a very expensive solarium/greenhouse, with all of my very expensive plants including the time and effort involved, all all the rest of the money spent to care for them, and then lose them during the day when I went to work or was away for the weekend. I think we really need to weigh all of this together. I may have been at this only a few short years but I really couldn't stand it if something like this happened. Folks in Florida can only do so much to protect themselves, property, and their plants/trees from huricanes. We can, however, definitely protect our investment with a generator. No different than paying for insurance. By the way...if you start doing some searches on these types of generators, most sites will have some sort of watt usage for appliances so you can get a rough estimate of your kilowatt needs. Then you can match up the size and cost of the generator needed. Fun huh?

there are also 'mr heater' propane heaters that are safe for indoors. they hook up to 20# tanks and arnt too expensive to run vs a generator.

but without electricity; u lose the air pump to inflate my 2x poly, my modine fan doesnt turn on, my wellpump, my fans for circulation...
if the power goes out, i have a generator cuz my system is based on e'.

Nathen, Our systems are based on electricity also. Everything runs off it. My response to the post was to simply say you better have a plan and you should have had it last summer.

We flip our switch OFF between our meter and our junction box. Not between the meter and the transformer. As the generator is running we have isolated our g/hÂs from the "main" .We are not hooking power to the electric companies circuit. Hence the switch. We then have a female 20a receptacle on one side and one 20a on the other that we plug the generator into. So in 5 minutes we are back and running. Works great saved our behinds more then once.

Fuels? the generator is gas. Always have plenty on hand. We also have kerosene heaters we can put in place if the heater decides to bite the dust. We have covered all our bases. Not sure why yours always has to be bigger but oh well. Oh and because I enjoy the conversations. Reread my post I didn't state we hook it up to the Main. That's 440 around here and I don't mess with that. And it's on a 50ft pole.

Stress, Yes when we have a power outage we have to turn off some of our fans and equipment to insure we don't over load the generator.

We also have an alarm that will call us on our cell phones to let us know the power is out. Seems to always happen at 2:00am!

For those who have standing pilot lights that's great but your blower motor is not going to be running with out the electricity. Also if the Heater is a hanging type all that heat going straight up will melt the poly. I wouldnÂt run a 250k Btu furnace with out the blower running.

Ohio You got the right idea. If we lose a crop we will not be able to catch up. So we just make sure we don't.
If you want to help her understand have her come out with you when the power goes out. SheÂll get the picture.

We just want to make it through the night or untill the power comes back on.

And fire up the generator once a month during the winter to make sure everything is ok and it still works.

Hi all,
I am in the planning stages of my GH. I am planning on a backup generator like you can find at the big box stores. HD has quite a few that have auto start when the power goes out starting at around $1900. if you go to the HD web site and do a search on home standby they have many to choose from.
FWIW
HotRod

For those who have standing pilot lights that's great but your blower motor is not going to be running with out the electricity. Also if the Heater is a hanging type all that heat going straight up will melt the poly. I wouldnÂt run a 250k Btu furnace with out the blower running.

Do you really think someone who requires a 250,000 BTU heater for their GH would not have a generator? Is that realistic? Of course not. I guess I don't understand where you are coming from...

$1900 for a generator? No thanks. I could restock my entire GH for $1900.

I have standing pilots like Weebus. Glass GH, no poly to melt. I have the HAF fans placed in such a way as to evenly distribute the heat. Without power I have uneven heat, but heat nontheless. With two heaters on opposite ends of the GH, it is enough, I believe, to keep things alive until the generator can be hooked up and power the fans. SB

electricity went off last winter-and my propane did great.sure,the circulation fans went off,but the temp stayed nice and warm.maybe uneven like stressbaby says,but heat.my heater is set about 6 inches off the floor.nothing melted last year.

Weebus, I read allot of post here and come to the realization that some folks don't realize what can happen. I just want folks to read the info and make an educated decision on what they should and shouldn't do and purchase.

I understand most folks here are hobbyist, some are not.
I fall into the not category as well as you. It's not a shot on you at all.

I can see some one letting their hanging furnace burn without the blower running because "they said it was ok on GW".

I don't have a greenhouse, but have wanted one for a long time. We live out in the country, and are just now getting a generator to use, just for a few appliances in the house during our sometimes long outages. I don't know much about it, but I think we're going to go with having an electrician put something between the outside and the service, that will allow us to (at the breaker box), pick out what we want to run. That's so much handier than having to have a window cracked to let the extension cords in from the generator.
But if I had a greenhouse, I would definitely go with the auto generator and propane. Everything in the darned greenhouse could be destroyed in 1 night (or even just a few hours), if you don't have back-up. I suppose the same is true for people with big tropical fish aquariums.
Trigger.....you have a nice setup. I'm assuming your generator comes on automatically? How does that happen?(that it can come on automatically).
Sorry for all the questions......I appreciate all the help!

Here is another idea that I have heard about (I do not have this idea in place, but I have considered it). It is for cooling and will only work if you have a misting system in place.

You hardwire a normally open valve to the misting system. With power on, the valve is closed and there is no flow. If power is lost, the valve opens and the overhead mist comes on. It is a stop-gap measure to keep things from overheating in the middle of the summer. I priced the valves last summer, and a 24VAC normally open solenoid was in the $250 range so I didn't do it.

i don't have a generator.my propane heater has a standing pilot and non electric thermostat.it uses no electricity.yes,i have 2 circulating fans in greenhouse,but the heater just has to run a little more with the fans off,and power out.

Oh, do I feel really stupid!

You know, I sometimes wonder why I even bother trying to have a greenhouse and run it with none, or very little external energy/power input.

Then I saw this thread!

""How do you deal with power outages?""

Well, personally, I make sure I have enough of those pre-packaged snack packs that you don't need to heat up. I stock up on books so I have plenty to read and I have a supply of candles so I can read the books.

Flushing the toilet becomes a matter of judgment as when the power goes out I have about four flushes left. (yeah you all really needed to know that...)

Oh back on the topic, the greenhouse is designed to survive without power as it is expected here. I knew why I had so many trashcans full of water out there. Thinking about it I should have a trashcan of water in the bathroom too, 10 more flushes would be nice......

stressbaby,

" If power is lost, the valve opens and the overhead mist comes on." For three or four flushes worth of water.

Them things are for city folks!!!!!

Catherine, there are backup generators available that run on Bottled gas (aka propane) and conversion kits to convet gasoline to Propane as well. If you have propane or NG heat, then shouldn't be much more to run the generatore on it as well

chris,what temps do you maintain?my greenhouse would overheat during the day,and my plants like 50 degrees at night.

Thanks Virgo.

I was just aiming for plant survival at night. No killing frost in there. During the day I would open the door and take the cover off a vent if it got really hot.

I only grow bedding plants and veggie transplants in there from about mid Feb to mid May. The rest of the year it is empty. In the fall I put a few tomatoes and peppers in there in containers I bring inside.

I was not joking when I said this thread made me realise something. I have been collecting fans, pumps and aquarium heaters so that next spring I can have a more controlled environment, and seeing this made me realise the more dependant I become on 24/7 power in there the more I have to work out a backup plan.

My record high temp in there? 140F in early Feb. Clear skies, outside air temp just about freezing and snow on the ground. The snow reflects additional light/heat in there. Plus the snow all around the greenhouse sealed all the cracks for me.

I don't know what size greenhouse you have, but if it isn't too large, you can use a kerosene heater or use a portable propane gas grill for emergencies. Just be sure to keep fresh kerosene on hand and propane tanks.

we just went thru an ice storm,ended up not losing power ontil this morning and was only out a couple hours.since i have a propane heater,with a pilot light,a power outage was no big deal.it was nice,not having to worry about the plants.this setup is about the simplest,and most reliable,as well as inexpensive.

Trigger,
I've been reading about the ice storm down there. I'm glad your system is working for you. We had a horrible ice storm here in the midwest last year, so hopefully we've paid our dues for awhile. It took us months to clean up afterwards, since we have so many trees. Hope everything works out okay for you.

For those who want full automatic backup, you could get a generator that has a sensor that starts up the generator when it detects main power off.

Also, you can connect to your mains in the house using an "Automatic Transfer Switch".

Basically, and the easiest way to do this, is you have a smaller, secondary breaker box. That box will have outlets to things like your fridge, specified lights and your GH (garage door too if necessary).

The Automatic Transfer Switch is connected between the mains (probably the main breaker box) and this box. The mains power and generator are connected to this switch.

When power is on, the switch routes grid power to this secondary breaker box.

When the power goes out, the generator detects this and auto starts. When it starts, the Automatic Transfer Switch can then route its power (from the genny) to the secondary breaker box. Works a treat.

I just fire up my kerosene heater in there. It works, but it's not really high tech. I used it for 5 days during the ice storm last year. The kids got mad because I lit the one in the greenhouse before I lit the one in the house, though. I told them THEY could bundle up for a little while. Also, I cooked soup and beef and noodles and etc on it. Made coffee, made pancakes. I even cooked some baked potatoes in foil in the greenhouse while I was cooking those beef and noodles in the house. It was really fun!
I have a generator now too, but I'm not sure I could really start it if my hubby was at work. It's a real bear to start...

lol Sandy......yes, those things can be really fun.....IF they only last a day or 2!