New Greenhouse

I decided to take the plunge and put up a greenhouse.

Here is the one I ordered. 12X24.

http://www.gardeners.com/Affordable-Grow-House/default/11210.prd

I had to supply a little wood. Everything else came with the kit which so far seems well thought out.

Got the base down this weekend.

I have some questions:

What do most of you use for the floor of your greenhouse? Do you leave the beds that were there or do you mulch?
How do you heat your GH? Electricity was is out of the question due to cost. Any economical alternatives out there?

I'm sure I'll have more questions as I move through consruction

BB

I would spray roundup and then put down smallish gravel-some size that is easy to stand and walk on.

I use vented propane heaters

BB, I have pea gravel as the floor in my 6 x 8 harbor freight one. Got 1/2 scoop from Luxury Landscape on 316 near Collins Hill. Not sure what it cost. DH had put in a 4"x4" wooden base. I put down landscape fabric and then about 3 inches of gravel.

Thanks

Tigerlilly:

Where did you get your heaters? Do you have one of the larger tanks?

Beclu:

I love Luxury Landscaping. I brought the most awesome compost from them.

BB

Thought I'd post on my progress. Just about got all the framing done

BB, I got all my tanks from the local propane company that i get the propane from. That way, anytime one of them goes down-they will come fix it right away. I have a 1000 gallon that is connected to a 500 gallon tank, and then a 500 tank for another grhouse. I get gas about once a month during the season.

BB,

I hate to butt in but I don't see anything protecting that beautiful frame work from the ground? Is it treated lumber?
A little separation from the earth would help things last a lot longer for you after all that talented work.

You have a beautiful yard and I think you are in for a lot of fun.

KW

Here's an update on my project. That pesky thing called work got in the way :-)

We have the ribs up and have added one coat of paint to the interior wood.

View from the side. The GH will get all day sun.

Here is a view from the rear. I am going to have the power company drop a power pole at the back of the rear for power. Project will be on hold for a little while I have someone wire the GH.

Some questions:

A lot of you stated you use gravel for you floor. I have a ton of wood chips left over from some tree work I had done. I was going to cover the floor with black plastic and then cover with wood chips. Are there any problems with using wood chips? (Insects etc)

I'm trying to decide on a heating source. This site gets blazing all day sun. But it still gets chilly here in Zone 7B and we start a lot of heat loving plants (Tomato, Peppers, Eggplant) I am looking for the lowest cost heat source that will maintain the temperatures that I need. I am leaning toward propane but would like to hear if anyone else has suggestions.

Thanks
BB

I would not go with the method of covering the ground that you are thinking of-the water will get trapped on top of the plastic and start to rot the wood chips-not a good situation for a grhouse. plus, I am thinking that you will not enjoy walking in rotting wood chips! I would still advise gravel on top of the ground.

If you are going to use plastic to cover the grhouse, i would use duct tape and cover/pad every sharp angle of wood that you have, and any other area that the plastic might get caught on, or rub against-such as connectors, nails etc. I would also go on top and check that wood for splinters etc.

I would use a vented propane heater for that size. I have never used electric, so I am not familiar with the cost difference with propane for that size. How are you going to cool it-speaking of blazing sun....?

It looks like your grhouse is coming along!

Thanks Tigerlily:

Sounds like you really know your stuff.

Sounds like gravel it will be. I still think I should put down some some of landscape covering under the gravel to keep the grass from growing back. What would you suggest?

This kit is actually pretty good in that they provided a hard plastic strips to put over nail heads etc. I did cover myself and use duct tape as a back up

What is a vented propane heater and how much do they cost to set up and operate? My space is 12x24. Electric heat is not an option due to cost. The only 2 choice I am considering are propane and some type of passive solar. On another GH thread, I read that the problem with passive solar systems is that you really can't control the heat release so you might not have it available when it's needed.

Thanks for your help!

I would spray roundup the first warm day that you have-in the grhouse and around the outside for about 2 ft. The grass won't come back if you kill it with roundup. Every summer, you can spray roundup when the grhouse is empty. I would stay away from weedblock etc-it still holds onto some of the water-esp when it is new. But you can try it-if it doesn't work, then you can rip it out, but roundup kills grass.

More importantly-how is your grhouse attached to the ground? I can't see any poles going into the ground. Is it attached to the ground?

How are you going to cool it? Are you putting a fan and shutters in when you get your electricity? That will run on a thermostat? You need a thermostat for the heater as well.

Vented heaters are heaters run on propane (or natural gas). SB is better at the mechanics of explaining the differences. I would call the propane company that you are going to get the propane from and buy one from them. No shipping costs and they will come fix it if it breaks. I would put it in a corner by your door, facing out, into the grhouse (kitty corner) and sink two 4x4's into the ground with a 4x4 going across the top that you can hang the heater from-so that the heater is about 8" or so off the ground. If you have that set up-the propane company will come install it for you. Then you will have hot air flowing under the bench where you are going to start your seeds. Put your bench about 3' away from the heater (where you can walk around in front of the heater, and not get water on the front of the heater). If you like, I can show you pictures of how mine are set up. If you are going with this arrangement-be sure to tell the propane company that you will hang it off the floor and where you light the propane will be on the side of the heater. Also easier to work on this way. I think that you need about a 24k btu heater, thats at 60 degree inside and 28 outside. Which is about what you need to start seeds and grow veges etc. I would even go for a 30k if they have it, but the propane man should know too. Make sure the company works with these heaters and has a man that can repair them.
If you want-i can take pictures of how mine is hung.

How are you going to attach the plastic to the wood? Are you doing one or two layers (with a space between them)? What kind of grhouse plastic is it?

Its the wood at the top of the gable that I am looking at in particular when putting the plastic on-you want to avoid pointy wood like what you have there, and anywhere else. It wouldn't hurt to have some grhouse tape on hand either for repairs if you happen to rip the plastic. It is great stuff and lasts forever on the plastic.

I am not sure of the price of a 24-30k btu heater-call your propane company and get a price and compare to what the online catalogs say. He might be able to give you a ballpark on how fast you will go thru a 325 gallon tank. Stressbaby has a similar size to you, a bit larger, but runs two heaters-he may be able to tell you.

Also-make sure that it is totally airtight-that means going around the outside of the grhouse and making sure there will be no air escaping under that 2x4 frame that is resting on the ground and filling in the dips with dirt-packing it under the wood.

One last thing! Pick a warm day to put your plastic on-so you can pull it as tight as possible. If it is cold out, then the plastic is contracted and when it warms up, it will not be as tight. Secure your gables first-always pulling tight and then the bottoms alongside the sides-always pulling. You need two people for that.

Let me know about the pictures if you need them.

BB, a couple of things...

The gravel is a LOT easier to put down if you do it before you cover the GH...you probably figured that out already.

The link you provide seems to show only 1 layer of plastic. The best think heat-wise that you could do is double that plastic layer and install a squirrel cage blower to inflate the space between the layers. That will move you from R-0.8 to R-1.4 or so, and that will cut your heat losses almost in half.

I have wall mounted Empire vented propane heaters. I like them but I have a brick kneewall and my heaters won't work for you. Use the elevated mount like TL suggested. Passive solar won't yield you any tomatoes!

SB

Thanks SB for pointing out the link! duh!! lol So you are stapling the plastic on. That is a lot of staples with a hand stapler! You generally put about 15 or more per foot. But if you use a hammer stapler, which is easier, you should put another layer of 2x4 on top of the base to have a wider base to aim for.
I don't see where they address attaching the grhouse to the ground-and I would seriously do that if I were you. I took 1.25" black pipe, in 3' pieces, sunk 2' in the ground right outside the wood base and attached the pipe to the base with clamps-every 3' or so down the length of the grhouse-both sides. Then taped the pipe before covering with plastic.
If you get a really strong wind (hurricane or storm) and the door blows open, your grhouse will be like a wind tunnel and it will move-I promise you. It will rack.

Thanks for all of your help. I feel like I should be paying you consulting fees. LOL

The GH is anchored to the ground using 2ft sections of 1/2 inch rebar every 3 ft.

I am going to lay the gravel and have the electrical and heating work done prior to covering the GH.

The covering is only one layer. I am having trouble visualizing the second layer you are proposing with the squirrel blower. Can you elaborate and what is a squirrel blower anyway? Does the blower need to run continuously? Or is it a inflate one time type of deal?

Are the propane heaters you are recommending attached to the frame of the GH?

Thanks again for all of your help.

BB

Thats good that the grhouse is anchored!

Shelves are good to do before the plastic too. Nothing like swinging a 2x4 into the plastic! lol

With two layers and a fan motor-it is set up like this-
You put your first layer on. Inside the grhouse in a corner, you have a small .5 hp motor that has a duct on either side of it. One side is attached to the plastic (using a wood frame that is attached to the base and has a hole in it that the duct is attached to (a dryer duct is fine). This duct draws air from outside and there will be a hole thru both layers of plastic (usually on the gable end)so the duct can pull in the air from outside.
On the other side of the fan is the other duct that goes to the plastic on the side of the grhouse. You have another wooden frame (small-duct is about 4" across) that has a hole in it for the duct, and you cut a hole thru the first layer-BUT not the second layer. After you put your second layer of plastic on-you can turn on the motor and it will start pulling air from outside and push it inbetween the two layers of plastic on the side of the grhouse. If you put your second layer on loose enough, then it will be able to push enough air between the layers so that you have anywhere between .5" and 4" of space between the two layers-thats a form of insulation. Any more space than the 4" and you will lose the benefit of the two layer, or if the second layer is pulled too tight and the air can't push it away from the bottom layer. I have read that it will give you an extra 10 degrees of heat at night. Not sure what SB means by cutting your heating in half-I wish! 10 degrees is good though.

Not sure if I explained it well enough.

Don't get discouraged, it took my husband and I 1 year to get my greenhouse together, but it's worth every bit of back-breaking hours we spent on it.
Take a look.

tiger lily, you explained it pretty good! I may have a pic around here showing how I hooked my squirrel fan up so will post when I come back home later. (Thing is though, I have mine drawing air from inside the g-house, not outside, and I love it because it tends to push warmer air in betweeen the two layers of plastic; sure seems to help keep it warmer inside.)

BB, my heater is attached to the frame of the g-house but I used 4x4's for the end frame uprights and those are much more sturdy than your 2x4's (or what appear to be 2x4's in your pic). I have a metal frame made of angle iron that comes off the framework to suspend the heater in the air.

Tigerlily has her 4x4's in the ground, separately from the framework, something you could easily do in your g-house. (I believe I got that right, Tigerlily?)

I'd suggest, as you and SB said, laying the gravel before putting on the plastic, however, you might want to run your electric lines either before putting on the plastic or after..it won't make much difference as far as difficulty whether the plastic is on or not. But, I'd definitely put on the plastic before you install your heaters and/or turn on the power to your g-house, I'd hate to see a downpour come on and your brand new heater, outlet boxes, etc are being exposed to it.

Congrats on this project! Sure wish I lived closer I'd be right there helping out!

Shoe

I will take some pics to. Horseshoe-there are various debates on whether to bring the air in from outside or from within the grhouse-and I forget them all! lol It was so long ago when I did the research etc. Has to do with the temp of the air and humidity or lack of, I think and why you want it that way.

Yes my frame is freestanding. I am not sure that if I attached it to the gable wall, that you would have room to work on it-would be a tight fit.

Thanks everyone for all your help.

I went and saw the propane guy today. While he didn't sell vented heaters, he came get one for me.

He suggested a 500 pound tank. That thing is huge and looks like it could heat a small house. Any recommendations on what size tank I should get as well as the BTUs I should have for my 12x24 space?

Thanks Shoe.

Yes Everything is 2x4s. Didn't think about the heater to think about reinforcements. I will have to give that some thought.

BB

Stumpenursery:

Beautiful project. What type of flooring is that? It almost looks like hardwood.

Thanks for the words of encouragement. I am hoping to get it finished by Valentines Day but I'd rather start my seeds in the house again rather than rush things and do an inferior job

BB

That is a layer of gravel, then we put landscape fabric on top, stapled it down so it doesn't move, don't want someone tripping and sueing. I noticed you where trying to find heaters and vent fans, try Morton's Horticultral Products, the link is www.mortonproducts.com, they will send you a catalog. Also try www.growerssupply.com, these are ones I use from time to time. They usually have hard to find stuff.
Hope this helps, keep the good work up.

Hey There BB,
may I share these pic's with you.......was my last year project putting all these GH's up and running before frost........I use an attic fan for venting........2 heat lamps & a walmart ceramic electric heater that has a high & low setting it was pluged into wall plug timer.....kept the temp around 50-60 on the coldest of night......and 4ml plastic which only last on season.

I'm in south Ga. we did have a few night dropping below 20.........but all my TENDER perennials come through with flying color.
Best of Luck to u!
Donna

This message was edited Nov 9, 2007 4:03 AM

and I Finish just it time!

BB, I did use about 6" of gravel, but before the gravel went down I dig 8" drained ditch on each side walls (which sch 40 PVC water lines are in the ditch also) and fill with gravel to ground level then landscape fabric........then add the 6" of gravel on top.

I've been in this GH for a year now, and it serve's my well! Hope your's is a great success too!
Donna

Wow:

That's a really nice GH Donna. Very Creative. I especially like the sitting area you have in front of them.

Thanks for the heating tips. How much of an impact did those heaters have on your electric bill?

BB

Oh BB, the setting area your refer to are rasied bed made with 2 x 8.
There 2' wide & 6' long. I use them for my stock plants (cutting's) easy to get too.

As for the electric bill any where from $30-50 per depending on the weather. The gravel helps hold heat.
GH #1 12' x 16' on left side has 4 heat lamps with 2 heater's with vent fan & 2 small floor fan, with 2 timer plugs (all are not use at the same time unless it's below 20 degree's.
GH #2 10' x 12' middle has 2 heat lamps
GH #3 10' x 12' green on right has vent fan, 3 heat lamps, 3 timer plugs & 1 floor fan.

I had research and plan for alone time, and knew I wanted gravel for good drained. and alot of water faucet's. I do have a second's misting timer ($100) that runs into each GH's if needed. Timer's are a wonderful to have for cuttings & sowing seeds. If you do buy ceramic heater's ($30) just make sure it has a thermostat, so the motor doesn't over heat. Our family business is electric motor's and my DH said those heater's are perfect
for the greenhouse. I keep mine on medium.

On outside holding beds (container's) I use drip irrigation & micro mini jet's. Go to Walmart and see if they have any 1/4 tubing on sale, last year I bought all they had, 50' was 7.95 on sale for 2.50. 1/4" tubing is connected with barb's to a 1/2' main tubing.
I know you didn't ask about my watering system, just thought I'd give you something to think about. I'll be glad to share more with later on if you like.

Oh, by the way I'll be hosting a Round -Up in 2008 you just might wanna join us here in Coffee County.

Have a Good One,
Donna

What a great looking place. The GH looks wonderful,but oh the pond in the background has won my heart.

Ok

Finally go my floor done

First I put heavy black landscape cloth over the ground

I then put down some crushed gravel. I told them what I needed it for and they suggested this crushed granite run.

Once that was done, I added an extra layer of 2x4s as suggested by Tigerlily to give me a larger base to work with when stapling the cover on.

I then trimmed the excess landscape cloth off and built our first bench.

So the only things I have left to do is the electrical work and the heating.

I work in the homebuilding industry so I'm try to watch my pennies. I am thinking of doing the interior electrical wiring myself and bring in an electrician to install the meter, breaker box and hook everything to the power. Has anyone else done the wiring runs themselves? Is it difficult?

And as far as the heating goes, I need about a 30,000 btu heater. What size tank should i get to power that size heater?

BB

BB I'm not sure why you would need a meter and a breaker box for this job! Your house already has those things. All you are doing is running a circuit or two from your home's breaker box to the greenhouse. That's all I did. I installed the electricity into my GH myself and I don't work in construction!

MollyD

Hi Molly:

This is quite a long way from the house (probably 50 yards or so) which is why I was considering a separate breaker. The power company is going to set a pole next to the GH and run power to it.

Can you give me some tips on what exactly you did?

Thanks
BB

BB all I did was run two separate line from the box (about 70') out to the greenhouse. Inside the greenhouse are junction boxes and off the junction boxes I ran lines out to outlets. I use propane and kerosene for heat so I could get by with regular outlets. Make sure there is a GFCI at the beginning of each run. That will protect all the boxes on that run. My outlets are for fans, heat mats, occasionally lights and radio. Nothing heavy duty.

My wires( outdoor grade for below ground) are buried just below the surface. I laid patio blocks over them as an extra safeguard.

MollyD

Put another breaker in your main panel and run the wire out to the grhouse in a deep (at least 18-24"...I think thats deep enough, mine is 36" deep) ditch, in which you can also run water (thru PVC pipes that you hooked into under your house). If you run the electrical wire (romex) you should put it in a PVC conduit. Once you get the wire up under and into the grhouse, you can set up a small panel for several breakers-I have one for the large fan (220 amp) and one for the small fans, one for the squirrel cage fan that blows the air between the two layers of plastic, one for outlets and one for the heater and one for the lights. I think a few are combined in one breaker-maybe not-I can go look if you are interested.

That was good where you added the wood at the base to staple to, but its only 2" high, and that is sort of narrow if you are swinging a hammer stapler. You don't want to miss/partially miss the wood and put a hole in the plastic. I have 2x8" wood on its side so I have the 8" to staple the plastic to. If you are going to do the two layers, then it is also too narrow-the plastic is folded at least 3 times at the base when you staple it, and so with two layers-that would be 6 fold of 6mil plastic to get on less than 2"...I try to get one layer higher than the other on the sides so its not too thick with the second layer.

A 325 gallon tank would last you a while. You could also do 2 125 gallon tanks that are connected.

Thanks

Sounds like I'll need to make a call to an electrician

What is a hammer stapler?

BB