# My new ''hot box''



## Stone (May 3, 2013)

I'm half way through building a greenhouse in greenhouse for over-wintering the seedlings and various warm growers. Whadayouthink?
All need now is a couple of front doors, a heater, some lights and a fan




Size is 2.4mt x 1.9mt x 0.5mt


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## SlipperFan (May 3, 2013)

I think you'll love it!


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## abax (May 4, 2013)

I think I love it. What a good idea. Please show the "hot box" when it's
finished.


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## Clark (May 4, 2013)

Cool!


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## goldenrose (May 4, 2013)

Funny, I don't think of one living in Australia as needing a hot box!


SlipperFan said:


> I think you'll love it!


the plants should love it more!



Clark said:


> Cool!


NO HOT!


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## NYEric (May 4, 2013)

Haha! Something I would never need in this apartment. Thanks for sharing.


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## Ozpaph (May 4, 2013)

Great project Mike.
Why inside the other house and not free standing?
Could you have used 'hot' mats on the standard benches?
How will you heat it and regulate the temperature?


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## Stone (May 4, 2013)

Ozpaph said:


> Great project Mike.
> Why inside the other house and not free standing?
> Could you have used 'hot' mats on the standard benches?
> How will you heat it and regulate the temperature?



I want to keep this at 20-22 min. So inside I will only have to raise the temp a further 5-7C without running the heater to the brink of collapse! (and save a bit on the ever rising electricity bills).
I'm going to try an old oil heater with a thermostat first and see how that stands up to the humidity. Heat mats are an option too but I want the leaves at the high temps as well. I'm going to try some Phalies on slabs in there as well


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## keithrs (May 4, 2013)

Your plants are going to be 'hot box'n it'... Huh oke:

Looks like a great project! I had thought about something like this but for cool growers if I ever get to build a greenhouse. I have no problem cooking plants... Even in the winter. Instead I have to resort to terrariums...


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## Ozpaph (May 4, 2013)

maybe try heating a large water bath with aquarium heaters. High humidity and stable temps fairly easy to control.


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## s1214215 (May 5, 2013)

Looks good. Though you would get better heat retention using thick wood, or 15mm glass (less so with glass), than the sheeting you use, and combined with lighting. A cheap alternative insulation is Styrofoam sheeting (1 inch).

What I fear you will find with this is that the heater will have to work hard, not heat effectively, and you will use more power to achieve the result you want. If you went with wood, a good LED (you can get some really powerful ones for planted thanks that have the right kelvin range at aquarium shops), and a heater it will be more energy efficient and stay warmer.

A passive heat source like a big vessel of water with a large aquarium heater will only heat to 40c from memory, and will not give you much boost to ambient temps.. I read that they only boost temps a few degrees over the outside temps. Its rather similar in effect to the greenhouse tube heaters that you can buy.

Brett


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## s1214215 (May 5, 2013)

Another way you could heat more passively is to install a radiator inside at the top of the box, and pump heated water through it from a source of heated water outside the box. The fan blowing air through the radiator will heat and the heat will be less drying than heat from an air heater. It will also provide air circulation at the same time.

If you are on facebook, check these links to my group on wardian cases. The later two links on a cooling method with a radiator fan, but you could easily reverse it with heated water as I plan to do once it gets cold enough here.

https://www.facebook.com/photo.php?fbid=10151560358494084&set=o.301381213230652&type=1&theater

https://www.facebook.com/media/set/?set=oa.452772924758146&type=1

https://www.facebook.com/media/set/?set=oa.454214581280647&type=1


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## keithrs (May 5, 2013)

I'm pretty sure as long as its sealed well and with a barrier to keep passive cool from coming up from the floor. It should work fine.


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## mormodes (May 5, 2013)

My only comment is to have something under the benches so one level doesn't drip on the lower ones.


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## Rick (May 5, 2013)

The metal frame construction looks really nice Mike.


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## Stone (May 6, 2013)

keithrs said:


> I'm pretty sure as long as its sealed well and with a barrier to keep passive cool from coming up from the floor. It should work fine.



It will be totally sealed all the way from the floor. The heater is going on the floor under the main bench. Warm will rise to the top and be circulated with a fan. Given the small area it should heat up ok?


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## Stone (May 6, 2013)

Rick said:


> The metal frame construction looks really nice Mike.



Thanks Rick. You have to make sure that after you've worked out the materials you need, steel, rivets, silicone tubes, etc. double up on EVERYTHING!


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## Stone (May 6, 2013)

s1214215 said:


> > Though you would get better heat retention using thick wood, or 15mm glass (less so with glass), than the sheeting you use
> 
> 
> I was going to use twin-wall polycarbonate as cladding for the whole thing until I saw the price! Good insulating properties but at $120 per sheet it would have cost $700!......... %^$# that! So I'm just using 2 sheets for the front.


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## Ozpaph (May 6, 2013)

if you dont mind the look - use 2 layers of bubble wrap on the outside walls for added insulation.


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## goldenrose (May 6, 2013)

Ozpaph said:


> if you dont mind the look - use 2 layers of bubble wrap on the outside walls for added insulation.


would 2 be necessary? (It's a box within a box....) Why on the outside rather than the inside?
I think bubblewrap has been my best investment.


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## keithrs (May 6, 2013)

Inside or outside... Either way doesn't matter in this case. But two layers are not needed. One more thing for Mike to think about.


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## Ozpaph (May 10, 2013)

two layers are better (depending on the type and 'size' of the bubble wrap) as the more 'dead' space air that's trapped the better insulating properties.
Outside is better as it will accumulate less mold/algae etc than if placed inside which is more humid and warmer - from experience!


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## Rick (May 10, 2013)

Bubble wrap is pretty cheap, and should hold up fine since it's not outdoors in the weather.

I found a much heavier clear swimming pool cover (super duty bubble wrap) that I covered my whole GH with this year. It's UV stabilized so should hold up for several years. It also was pretty cheap, and looks better than bubble wrap (since it doesn't have all the taped together strips).


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## Bob in Albany N.Y. (May 10, 2013)

Rick, can you tell us more about this product, such as cost, where to get it and so on a so forth. Heating my greenhouse cost as much as heating my home and that doesn't make for a happy wife :-(


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## Stone (May 10, 2013)

Well its up and running! So far no problems with heat retention but its still quite warm here this year. Hygrometer is showing 100% humidity but there are no water droplets anywhere Fan is on 24/7. min temp is 18 -20C.


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## Ozpaph (May 11, 2013)

get a data logger if you really want to know what happens 24/7 - like this - http://www.ebay.com.au/itm/Temperat...U_Decor_Furnishing&hash=item2eb8b5c087&_uhb=1

I found it to be invaluable.

The swimming pool UV stabilized 'bubble wrap' costs a lot in Oz and the dark blue colour would cut out nearly all light transmission. Good idea none the less.


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## Stone (May 11, 2013)

I think I need more light but its nice and tropical in there


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## SlipperFan (May 11, 2013)

That was quick!


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## Ozpaph (May 11, 2013)

Very nice.
In my smaller hot-box I found blowing the fan onto water help prevent drying out. By adding an aquarium heater to the water it also help stabilize temperatures.


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## biothanasis (May 12, 2013)

Nice project!! Nice result!!!


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## keithrs (May 12, 2013)

Nice!!!


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## abax (May 13, 2013)

Very neat construction and it looks very clean. I like clean. I want to see
a photo six months from now after the algae and dropped "stuff" accumulates. My greenhouse was fresh, clean and new many years ago,
but I hardly remember it now. ;>)


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## keithrs (May 16, 2013)

So how hot do you think it will get on warm days? Do you have a way to cool it?


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## Stone (May 17, 2013)

keithrs said:


> > So how hot do you think it will get on warm days?
> 
> 
> Don't know for sure but it shouldn't get hotter than the rest of the GH.
> ...


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## Stone (Jul 4, 2013)

Well I'm convinced. Heat rules! After just a couple of months almost every plant in there is responding. Even cool growers like venustum and charlesworthii are moving well. The brachys have all put out a nice strong new leaf. I would estimate they are growing 4 times faster than in the main g/h last summer judging from how long it normally took to get the same growth without the constant heat. And all this with very minimal fertilizing. So to my mind its conformation that environment trumps technique!


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## keithrs (Jul 4, 2013)

Stone said:


> So to my mind its conformation that environment trumps technique!



All Day, Every Day! Even growers with the most sound technique have trouble growing "hard to grow" plants with out the correct environment. Put them in the right environment and all of a sudden they be come fairly easy to grow.


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