How do you heat your greenhouse?

I didn't do very well last winter. I lost all of my tropical hibiscus. I have 7 new ones and I need some ideas to keep them warm in the winter. What works for you?
Julie

I'm using one of those cheap-o heated-oil heaters (with the array of vertical fins). Seems OK but would like to hear about other options... Propane, electric blowers, etc. BTW our gh is small, 9x9. Just big enough for the bare essentials :)

I used a small electric blower last year. Will try and get one a little bigger this year. My GH is 12x12
Winni

i keep mine in the house!

I have a wall mounted propane heater, however, with the cost of fuel now getting out of sight, I am not going to heat my green house....Living in Northern Michigan, it would just be too costly...come April when I start my seeds, it gets warm enough in there during the day and at night I just cover the seedlings up.

Deann

come march i will start mine ;)

Here in Alaska we dont heat the greenhouses until April 1st.
Went we do, we use Toyo-stoves. They use #1 heating oil.
The size we use put out 22,000 b.t.u.'s. Our gh's are not insulated, but we have found the stoves will keep the gh about 40 degrees above the outside temp.
So far so good, but if we have a weird spring and the temp drops to sub-zero temps, we will have to kiss off a couple of hundred flats. Pray that never happens. Would have to send Weez in for mental health treatments.
The ol' Tom Cat, Dennis

My first GH was just an old plastic sheeting one, I did sheet both the inside & outside. It is 6X8, I heated it with candles the first year then switched to one of those elect oil filled heaters, it worked fine on the lowest setting. I also put it on a timer (plug-in type) so it wasn't running in the day time. The candles kept stuff from freezing, 5 candles kept it 42 on a 20 degree night. I have a gravel floor & just put them all on the floor. seemed to work ok, but founfd myself spending more for candles than for the elect. for the heater! Plus I had to remember to go light them around 10 or 11 at night.
My new GH is 15 X30, right now it does not have any heat, I have been jumping from oil heat to solar. It may get the candle treatment as there is no elect. down there & if we get a cold snap before I decide! It is full of Brugs & a Lemon tree. It won't be kept warm, just 45-50 this season. I use my old small one for a seeding house & to keep the more tender tropical plants over winter. It's kept much warmer.

I have a small 8x8 Rion and I used a ceramic heater from Wal mart ($30) last year, and it worked just great, It has a thermostat and I kept mine set at 60, and was also able to use the lower wattage setting.

Blessings,
Awanda

JuBabe, --how big is your greenhouse? Do you have one layer of covering or two? I have used many kinds of heating, but alot depends on what you are working with, and what you want to do. Do you want to keep things from freezing,35, -to 40 deg, or do you want to grow Tomatoes, 55 deg min at night? I have kept things from freezing with 55 gal drums painted black, and with a compost heap with pipes ran through it into the greenhouse. But -- I have learned that if you are raising a crop of temperature sensitive plants, you need a good heat system with a reliable thermostat. I have used both gas and oil, with good results.--Michael

I am planning to use one of the finned oil heaters, but was wondering about the black container filled with water inside the gh. Has anyone tried this? Can it really keep the gh temps a bit warmer? My gh has a raised floor about 6" above the ground, so will need something to keep the floor warm or else block the openings around the outside.
I'm still experimenting how to keep the place warm. Planning on checking styrofoam panels for the inside walls also. Anyone ever do this? Thanks for any info, Doris

I have used 55 gal drums painted black and filled with water, they do help. but you will need the insulation mentioned, to keep the heat in the greenhouse at night. the plants near the barrols did well for me, but two layers of plastic with air between, didn't do enough to save tomatoes. It did do enough to save lettuce and cabbage family crops.The low temp [outside ] I had when using this method was -12, The inside temp of the greenhouse was +35. I was in Utah at the time and had veggies all winter. Where I am now, ventilation is more of a concern then heating, but I still have to heat off and on in the winter.

I thought of doing this.. thought that the barrels would make good supports for the plant shelves and serve a double duty..

I've got a Solar Star greenhouse from Farm-tek that is 18 x 24 with a gable roof. It's my first time going into winter, and with orchids and tropical fruit/citrus trees, it'll be interesting to see what the gas bills are this year! I've got a 75,000 BTU hot Dawg heater and the thermostat set at 52 degrees. Yesterday and today we've had lows in the mid-30's--a touch of the white stuff this morning ! In case anyone is interested you can get bubblewrap from a place called www.cuttingedgepackaging.com in Toledo, OH. It's something like $15 a roll-- two 2 foot wide and I think 25 feet or so long rolls of the 5/8" or 1/2" (the bigger bubbles). Sorry I don't remember the details but I ordered them a while ago and am currently at work. But it beats some of the prices I've seen google-ing bubblewrap-- some places wanted $75 for a roll and $25 to ship it Fed-Ex. I put 2 layers on the end walls, and I tried to do a single layer from the ground to about 6 feet up. Hopefully we'll see what happens this winter. I never planned on so many hurricanes wiping out the drilling platforms, etc. and gas/natural gas prices sky-rocketing like they have the past 2 months or so. :( Hope everyone is doing well in Florida and the southern states.

Thank you for posting that orchidman! Oh, the rolls are more than 100 feet long on some which makes them very reasonable! I have been thinking about this myself.

Has anyone tried the furnaces with the water pipes that run through the flooring? I think that would be awesome! The stove actually goes outside which leaves all the space inside.

The water pipes in the floor work, if growing plants within 30" of the floor, or growing short crops in the soil, [lettuce, bell Peppers etc] if you are raising taller plants or climers they will get cold above 30" from the floor. [this was my experience] --Michael

Thank you Michael!

We have 6 different greenhouses 5 of which are tropical to subtropical one greenhouse is for hardy palms and gets around 30 to 40 at night karosine is the heat source. The two new greenhouses are 45 ft long and 20 ft wide they have radiant heated flooring. The cement floor has tubes with hot water pumped through it. To keep the floor at 65f. Two other greenhouses have hot water pumped through radiator like fans that throw the heat out. The radiant heated floors are the best source of heat I have seen. We use a heatmor wood burning stove to heat these 4 greenhouses. We get as low as -10f and keep the greenhouses no lower than 55f. The largest greenhouse is 80ft long 30 ft wide 22ft roof.

here is a pic of the small greenhouses getting the flooring put in.

I have heard that the newer systems with concreet floor work well with the water pipes in the concreete, --I know that the systems that put them in the growing beds [dirt] didn't work well enough to raise tomatoes when they got over 30 " tall -- glad to know that they work. Did you put insulation under the concreete?-- I supose that someone will come up with a system for organic veggie growers--

bwilliams....you are real serious about your greenhouses....I am assuming you are in business....

Yes we run a nursery and me and my father are both hobbiest tropical plant growers. Our collections rival that of large botanical gardens. I have oddities from all over the world and work on making new hybrids. 5 heated greenhouses and one large coverd greenhouse not heated at the moment.