Proper heater placement in GH

Hello all,

We now have the heater for our 8 x 14' twin wall polycarb. GH.
It is a 240 V. 5700 watt, 20,000 BTU madel w/ a fan. It has a nice adj. bracket that allows for floor or wall mounting.
It measures about a foot square and has an adj. thermostat and a 6'cord.

Our GH will be insulated with foil,dbl bubble. dbl. bubble, foil.( 4 layers), this will be on all sides except the South side and probably clear poly on that side.

My question is,.. where do we mount this heater for best circlation, plant care & safety?

The directions say mount on an end wall parallel to an outside wall. They do not specify height.

My wife says to mount it on a side wall about in the middle about 4' +/- as this will help keep it dry.

I think like my wife but I would mount it lower to help keep the floor warmer and also the in-ground bed.

We will be using 2 small fans to help move the heat around inside also.

Well, that's everything I can think of.
What is your advice on my little dilema?

Thanks for reading this and all advice,
KW

Here she is,

KW

I'm not so sure I'd want to block all light (foil) from three sides. Just the north wall should be sufficient. Unless, of course, the majority of the plants in there are shade lovers. The double bubble would be fine, I would think. It would help insulate, yet still let in a significant amount of light.

If most or all of the air leaks are sealed, I'd opt for following the instructions that came with the heater. I'd also mount it just off the floor. Remember, heat rises. If you put it at 4', you'll likely not be happy with the condition of plants close to the floor, IMO.

My $.02
Eggs

KW, I have that same heater for my 12X14 GH. I mounted mine up high, about the middle of the GH. This will be my first winter with it so I guess I will find out if that is the right place or not. I tilted it down so the forced air is down, not up. But as Eggs correctly states, the heat is going to rise. I have two fans that run continously, and one of them I will point towards the peak. My theory was that as long as I am moving a lot of air and don't allow it to collect at the peak it would be better mounted high, and out of the way of all the water. I think no matter where you mount the heater the heat will rise to the peak. So it is important to have good air circulation to keep the temps even throughout the GH.

Just curious if you have a backup source of heat, and if so what it is.

Nautical

get outta my head, nautical! =P

I have two fans, running continuously, one low and oscillating, and one fixed, high, and aimed towards the center of the GH.

I have mine hung about a foot off the ground, but most importantly, it is in a corner at a angle, near the door. I don't have any plants near it. The closest shelf is about 2' away. My heaters are larger-up to 200k btu, so they are all about 3 or so feet high, which is why theyare so low, but they are all far away from water. I would think that you want your heater at the end of the grhouse and let the fans bring the heat to the other end.

I also think that that is a lot of foil-maybe too much. I have clear plastic on all sides, and I would hate to give up even one side to shade.

Mine is like tigerlily's, 200,000btu and 3 ft tall or so, but it is hung from the ceiling so it doesn't blow heat directly on the plants. And yep, heat rises up but I have a fan running non-stop that keeps the hot air circulating and also prevents dead-air spots in the g-house (reducing chances of diseases).

I keep hoping that my heater will finally give out one day because then I'd replace it with a floor level heater and have it shoot the heat out under tables that would be lined up in front of it, that way the plants on the tables would be warmed from the bottom. (I can even see that system being used as a large rooting area were the sides of the tables wrapped in plastic, holding the heat under the tables more so that it would definitely rise upwards and under the rooting pots.)

Shoe

that is what I do with the heat, Shoe, and it works great! I have the thermostat halfway down the grhouse (about 50') set at 60 and up by the heater, the temp is anywhere from 65-70. A 200k puts out a good bit of hot air and I germinate all my seeds and cuttings there. I just put 6 plugsheets together and cover them (tucking under the ends and sides) with a piece of plastic and lift them every am and mist with hot water, then recover them for the day. When I am done with the germinating for the season, then I use that area for plants that I am trying to speed up growth (like tropicals etc).

Shoe, it is so hot under there that I have to put plastic under the plug sheets to prevent drying out because of the heat-and anything that is not under plastic (like cuttings) gets watered at night as well to make it thru the evening or they would dry out. Once I am done with the germ, then I remove the plastic as I want it really hot under there, and the flats are so tight to each other that I don;t think that I am losing a lot of heat . Also Shoe-my heater is hanging also, I just hung it from two 4x4 that were sunk in the ground and have a 4x4 at the top of the legs and drilled holes in the wood for the screws, so I think you could change the position now if you want to. Let me know if you want to see a picture of what I did.

It is useful to have different temps in different parts of the grhouse so you can grow a wider variety of plants. All the colder weather plants that I grow, such as petunias, go at the far end where the temps are a bit cooler than 60.

Thanks, tigerlily! Your "rooting tables" sound like a winner to me! Any yeh boy-howdy(!), those big heaters really put out the heat so I can imagine them drying out things a bit too fast, and too much. Good idea using the plastic underneath as well as wrapped over the plug sheets.

I tend to root some things in mum pots or gallon pots (I can get quite a few gardenia or fig cuttings in those) then put the pots in plastic grocery bags, or Walmart bags, with the bag "handles" at the top so I can easily close or open them as needed. Hopefully I could still continue to do that when I move my heater to be set up like yours.

As for my heater, unfortunately I can't put it too close to the ground because I have to service it from the bottom. In other words, the door to the burners/pilot opens from underneath instead of from the back (like floor models would). However, this heater is going on 8 years old and is beginning to show its age; although I hope it makes it one more winter it looks like it'll be a "cross my fingers" issue!

Thanks again. And one day when I come to Raleigh perhaps we can get together and chit chat a bit, eh?

KeyWest, sorry to have gone a bit off-topic. Hope you enjoy your greenhouse!

Shoe

Sure Shoe (say that 5 times fast lol), let me know when you are going to be in Raleigh-love to talk grhouses/growing with you. Actually the plastic is going back up on all 3 grhouses Tues-I can't think of a better time to drop by!! lol I need to remind myself to get about 10 boxes of staples

Mount it high...?
Mount it low..?
Which -way -do -I -go...?

A LOT of good advice and from the Pro's who Know ! I am very lucky to have such advisors and I thank you very much.

Still thinking though, still in a semi-dither.........

My insulation is preassembled all in one sheet. It has 2 layers of dbl.bubble in the middle and is covered with aluminum on each side.
Perhaps because I AM listening..( tigerlily & Eggs), I will leave some of this insulation off the east wall also. Maybe I can use clear stuff over there.

Nautical, you have made great strides my man, approaching 3 star status! On a serious note as I read your words I see you have both feet in the game and my hat is off to you!
To answer your question about auxillary back-up, when I did the stone wall foundation I added a U shaped 4" PVC pipe that goes from the outside buried in my garden to the GH inside as an access for a propane hose etc.
I at this time have a large Mr.Heater or heater buddy that puts out about 18,000 BTU, I believe.
In case of pwer loss I will use that for now.. Your GH is beautiful!

Streebaby? come on in please. I have to keep some beautiful plants warm that a good friend gave me.

It's all good fun. Isn't it.

KW

KW, Thanks for the kind words. I really have enjoyed the GH this summer. Whiteflies and all. Was down to 55 this am so I have to really get moving with putting plants inside.

I have a small propane heater as well, I guess that should work in a pinch.

Can I ask where you got that insulation? I have thought about putting bubble wrap on my north wall but not sure how I would secure it. Is that material pre-cut to fit between your panels?

I finally finished the outside of the GH. I loved your stone work, it looks awesome. I ended up using cedar because........well because it was easy and I was lazy. :) I will include a couple of before and after pictures here......sorry to be getting off topic.

Nautical

As of 10/9/07

One more.

nautical, I gotta say that your GH is looking GREAT!

tigerlily: Since when are petunias "colder weather" plants? Did you find some arctic species, and you're holding out on sharing them? Hmm? =P

eggs-petunias are considered "cooler weather" . They handle frost on the leaves just fine in the fall and the spring. About the only variety that we can use here in the south are the wves and similiar ground cover types. The heat makes the grandiflora bolt and get leggy. In late March, when the temps are starting to warm up some at night, they are the first to go outside for me. The temps at night are regularly in the high 30's and the petunias are still very small-about 2" across, but they love it. I use the cooler temps at night to keep the growth down instead of using growth regulators.

When i said that they are cooler weather-I meant of all the spring crop that I grow. The waves also come back each year in the ground.

I got ya. It just struck me as an odd statement. I'd say 90% of the petunias I've ever grown [1] absolutely flourished when it got hot out, and as soon as it cooled down, there was nothing left but foilage, which rapidly got ratty-looking. To me, they're much more of a hot weather plant, as opposed to pansies, in my area at least.

[1]. Mostly Wave and Multiflora doubles. I've grown a few Grandifloras but they just don't bloom as much for me (yes, even when it's cooler out). Could be a zone thing. *shrug*

Nautical,

Try, www.radiantguard.com. This is the Co. I purchased it from.
The foil is 4' wide and 125' long = 550 sf. 5/16" thick. I has 2 layers of Bubble Insul laminated between 2 layers of Radiant Foil. It's fairly tough too.
Not cheap but I have used it on a number of projects & it is very handy stuff.
Free shipping thou, ha.

After working with the stone except for corners & stairs, wood can be harder to make look beautiful and yours came out that way, pissa.
I did lose a couple pounds lugging all that stone though.

I'm probably going to mount the heater up high in the middle shooting down but I'll try to install the plug so I can move it to the end if needed. But still thinking on it.

I cleaned 2/3 of the GH today (inside) and after I finish the rest I will put the insulation in & mount the heater. The shade cloth came off today also. The aluminet sttod up very well, still looks like new.

I wonder what it's like to sit in a warm Greenhouse while the snow is falling???

The fat guy fishin is me down the keys. Key West is my state of mind.



KW