Good day, I'm in the process of building one of these for my greenhouse. Just wondering if anyone else built one or use one. If so, how do you like it? What are the pros and cons you see? I plan on building one using a 30 gallon barrel vs a 55 gallon barrel. I got my kit a month a go. I know winter is 3 months away but you have to plan and be prepared now or your fig trees will freeze. In case you're wondering what this thing is, here a nice video:

Here is another video....

Hi snaglpus,
Here go my comments:
People here use those half barrels as barbecues . So we cut the barrels in two pieces - could be done on both sides - the longer one with the barrel laying on the side or with the barrel standing.
I've done so too. Unfortunately, those won't last a year and that is with a fire on weekends only... You might get short with the barrel getting holes from the heat.
The iron gets cooked from the fire and will sort of get thinner and starting with holes and rust.
Another thing the guy doesn't say: How do you remove the ashes. He does let it go off and cool as he is not using it all days - he mentions using a couple times a week.
If you're planning to use it all winter, you may have to choose warmer days to let the furnace go off and remove the ashes.
If you try that system, I would use a water pipe to get the heat more uniformly distributed in the greenhouse.
Because there is no way to go under a certain heat, you need some volume in the greenhouse and put the trees at some distance, or you'll cook the trees.
There are woods that will produce more heat; you should target wood burning slower and producing less heat as it will help with the barrel lifespan.
Good luck !

PS: I hope the children of that guy are not as terrible as mine, or he'll have to run to hospital some times ... Mine for sure would at some point ride or jump the barrel or touch it to be sure that it was really bloody hot... Or would stumble and fall near the barrel...  Not really secure as a setup... The barrel should be caged.

If you're heating with wood, a "rocket mass heater" is, by far, the most efficient way to do it. Permies. com has tons of info on it. It's an inexpensive DIY project. I sure wish I had known about it before I built my existing setup. You just have no idea how much wood it takes to heat a poorly insulated building, like a greenhouse. I've added the insulated riser in a barrel on the back of an old Fisher stove, and boosted it's efficiency way up. That's your highest and best use of that barrel.

Thanks for your comments. The purpose of my heater is JUST keep the the greenhouse around 40 degrees. My winter in 8a are not that bad. However, we do get rare 5 degree temps and some temps in the 20s in November. So, I don't want the heater to burn red hot.

I like the rocket heater idea.

I'd also like to add that I just got my barrel.  I went with the 30 gallon vs the 55 gallon.  Again, I'm not planning on setting my GH to 70 degree.  I just want it to be around 40 to 50 degrees.  I nice gentle warm air is all I'm after.  I will post pic of my heater when I complete the job.

Since I started this post a few weeks back, I've been feverishly looking at other methods for heating my new GH.  Right now, I'm in the process of laying down the brick floor.  I looked at a lot of videos and information on the rocket heater.  From what I've seen, it just takes up too much space inside a GH.  My little barrel stove might be the cheapest way to keep it above 40 degrees.  But if temps drops down to 5 degrees like it did in January TWICE in one month, then I will definitely have to watch the GH closely.  But don't worry I've got a plan!

Now, that the fig festival is over, I can plan my winterization plans for this year.  Weather in Charlotte has started to change.  The nights are in the 60s.  The mornings are windy.  There is more dew on the leaves of my fig trees.  The critters are on the move through my area again and the wooly worms are on the move too.  But summer is still in full swing in Charlotte.  It was 90 yesterday and 88 today.  Now is the time to start planning for winterizing fig trees.  I've got a lot of frost blankets ready to cover a few trees in the ground.  But I can't forget my new GH.

I don't want my GH to heat at 70 degrees. My goal is to keep it between 40 and 50 degrees inside.   Today, I will start building my stove.  I will post pics as I build it. 

Good Luck!

Hi,
Keep us posted !
5°F/-15°c shouldn't be a big deal for fig trees.
Did already think about digging a big hole and laying the pots inside and then cover the hole for the winter, and unbury the trees come Spring ?
My 80 liters trashcans are ready for next winter (no additional cost for that). I just need to buy some cheap dirt from the nurseries to fill the trashcans with, to have
a heat reservoir.
But let me first harvest the main crop first. I just harvested some 30 "Dalmatie" main crop figs today and more started the ripening process - They swell .

Hi Alan,
Don't you use straw or black plastic laid flat ... Those are magnets for rodents ...
That's the reason for me to use dirt from the nurseries. That dirt stores and releases the water in a good manner as well - here in my Zone7.

Project completed!

That looks great Dennis!  Let me know how it works!  I'm trying to find the time to run natural gas pipe out of my basement and into my greenhouse to put a blue flame heater in, but I wonder if it will be worth the cost.  I'm sure once December gets here and I get bored out of my mind stuck inside, I'll reconsider :)

Will do Nick.  My neighbor across  the street is an aircraft mechanic for the airlines.  He told me NOT to put the heater inside because it will generate too much heat and I won't have anyway to regulate it except opening vents and doors.  So, here is what I have.  

I have a large kerosene heater from Japan.  It's the first kerosene heater I've ever used that did not smell like kerosene!  It's one of those burn clean types.

 I also have a brand new propane heater.  It's theromatically controlled.  The problem is I can't use a small 20lb propane tank with it.  I hve to use a 100lb tank.  This might be my best option.  However, I have to consider where to place this tank?   And how much is it going to cost me in propane?

The barrel stove sounds like the best option but I'm not so sure!  Since my GH is super thick plastic, I have to make sure to have enough stove pipe above  the top or I could burn the whole thing up!

The good news is, at least I have options.  I think I'm gonna invite my neighbor over and get his opinion.  He's a "Macgyver" and is always outside building something.

Now that my stove is built, I can get a cord of wood for $50 bucks.  I'm thinking it will last me through winter.  My goal is to keep my GH between 40 and 50 degrees.  WIth a wood stove, now I have to make a hole inside my GH to accomadate the stove pipe and vent.  That's another task to consider.  I like the propane option because it's theromostatically controlled and my GH has 4 vents that will open if temps reached 70 degrees.

Is it just me, or is there something that sounds kinda cozy about sitting in your greenhouse in front of a wood fire while it is 20 degrees outside? :)

Hey Dennis.

I'm curious about which heating option you decided to go with for your GH. Did you get the chance to test out the wood burning barrel yet?

There is one option for the wood burner you might not have considered yet. You could keep the barrel outside of the GH and run lines containing water that is heated by the wood stove. Basically a small scale boiler with radiators inside the GH. Would be safer and would save space inside.

I saw a good youtube video on something like this a while back. If I remember correctly it can be built fairly simply as a closed system. The water circulates by the expansion and contraction of the water being heated and then cooling and automatically repeating the process on it's own. I assume you'd have to have a blow-off valve in there somewhere to prevent a possible rupture. 

In the vid I saw, I think the guy was building a wood burning water heater, but with a couple small tweaks, it could easily be used to heat a GH.

Hi Bill, at the moment, I have a kerosene heater inside. I ran out of time with moving trees around and other stuff. With the kerosene heater I can adjust it down to low and it will keep inside temp above 40 degree which is my goal. So it temps outside reach 25, the GH will be 40 degree at the farther spot from the heater. I like that but if temps reach 10 or 5 like last year then my citrus will be in trouble. I still have a lot of Meyer lemons and kumquats on and they have turned yellow but not ready yet. I've already picked 19 lemons! I got 14 more trying to ripen. I will install the heater in March. I like the radiator idea. I need to research that more and make a decision. Thanks for pointing that out.

I like this GH. Even though it's plastic, the thick fiber inside make it super strong.

My dad built a wood burner for his greenhouse when I was a teenager.  The fire box, a huge ugly thing was outside and the vent pipe was welded hot water tank cores that went horizontally inside the entire length of the house. One night he neglected to adjust the damper properly and woke us up in the wee morning to have emergency re-covering of the greenhouse since the vent pipe got so hot it melted the plastic. It was like a giant rocket stove blaring full blast and the pipe was red.   

Saw this the other day and thought about you guys with the heater ideas.

http://www.sportsmansguide.com/product/index/hq-issue-camp-stove?a=1905681

Leon,
I almost bought one of those on eBay about 3 months a go. However, i think it will be too small for my 12 x 20 GH. My GH is up but I've been moving trees around in and other places and ran out of time. So, Last week I orders a kerosene heater. I keep the inside temp right at 40 degrees. But, if temps drop down to 20, my kerosene heater wn't be enough. So,this weekend it's suppose to be 70. My vacation starts this weekend so, I've got to seal up the ends on my GH first then install my barel heater. I'll post pics from this weekend's work.

This sounds like a great option for heating a greenhouse or hoop house in the winter!  Thanks for posting.

Go to sportsman guide military surplus and check out the US Military stove,heater combo.

Oh!  Ok.....I see it now....watched the video too.  Hmmmm.......

That's pretty neat.  I might have to look into this.

thanks, Leon!

My pleasure Dennis!