Author Topic: Greenhouse anyone?  (Read 47676 times)

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JMaris

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Re: Greenhouse anyone?
« Reply #27 on: May 16, 2010, 06:34:49 AM »
Is the poly you used the 6mil thick stuff? The 6mil is all I have been able to find online.

Hilltopgrange

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Re: Greenhouse anyone?
« Reply #28 on: May 16, 2010, 07:04:31 AM »
Your best bet is to contact a local horticultural supplier, if they don't have it they will at least know where to get it. I cant remember the spec on the cover as it was so long ago, I have just had a look to see what it says on it and it just carries the trade name politherm plus.

Russell
« Last Edit: May 16, 2010, 07:06:58 AM by Hilltopgrange »
How many windmills do I have to build to become a windmillologist?

SteveCH

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Re: Greenhouse anyone?
« Reply #29 on: May 16, 2010, 08:52:21 AM »
There is a company by the name of FarmTek which has been sending me catalogues for years. I've never done any business with them, but they carry a lot of hoop, or tunnel, greenhouse supplies. I have no idea how their prices compare with any others, but they do list many items. Might be worth a look to get an idea.

Again, I've never done any business with them, though I've been getting their catalogues for at least fifteen years so they've been around at least that long. They have a web site.

JMaris

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Re: Greenhouse anyone?
« Reply #30 on: May 16, 2010, 09:10:10 PM »
Thanks for the website. They have a ton of stuff on there! Im really interested in their hydroponic systems. Ever since I read about them, I really want to give it a try in the future... but Im not trying to get ahead of myself. I need to get the greenhouse going first. We are supposed to close on the land tomorrow. I have a long "to do" list for after we move in. The greenhouse isn't #1 on the list but it is fairly close to it.

JMaris

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Re: Greenhouse anyone?
« Reply #31 on: May 17, 2010, 08:56:16 AM »
So what do you guys think about using some thick wall PVC for the frame rather than metal? I was thinking like 1&1/2" or 2"id schedule 40. That would be a lot cheaper and easier to use than steel.

TomW

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Re: Greenhouse anyone?
« Reply #32 on: May 17, 2010, 12:00:04 PM »
So what do you guys think about using some thick wall PVC for the frame rather than metal? I was thinking like 1&1/2" or 2"id schedule 40. That would be a lot cheaper and easier to use than steel.

I think you would find it was too brittle in the cold and too pliable in the heat. Was my experience anyway. Our temps can be 100+ F in summer to -40 F in winter, however.

On a hot day here you could clamp one to a post vertically and by days end it would bend over from getting soft in the heat of the sun in the open. Behind heat retaining sheeting it would be worse.

Just my experience with PVC as structural elements here in the upper middle coast area.

Tom
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Hilltopgrange

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Re: Greenhouse anyone?
« Reply #33 on: May 17, 2010, 04:18:02 PM »
I personally would not use plastic tube for anything bigger than a cloche. As Tom pointed out it is going to be susceptible to temperature both high and low. I toyed  with it before I built this one but it failed miserably when the first storm hit it, mind you a glass 8x4 glasshouse from the diy store also failed here. I am in Northern Ireland, we don't get very hot or very cold conditions but we do get a lot of wind and rain but even in our cool climate it can get very hot inside. My main concern with this one was the wind, if a hoop was to fail in a westerly gale the whole cover would take off and land somewhere in Scotland. The other snag with plastic is UV as some types just disintegrate in a very short time.

If you don't fancy bending the steel for the hoops you could get a local fabrication shop to do it for you. I bought a hydraulic bender for less than 100 delivered and bent them myself. The whole thing bent, built and covered took less than a week to complete, its not as big a project as it looks but it does require some planing. I built mine on my own but I did enlist the help of my wife when it came to fitting the cover.

The other option is to buy a factory made tunnel but they are not cheap.

Where are you and what sort of size are you thinking about? 
If it is smallish you could use a smaller diameter tube or maybe even aluminium.

If you are in a hot climate you will need to think about how your going to cool it. A hot day in our climate is about 70f maybe as high as 80f but that would be exceptional and rare but even at 65f outside you could not spend any length of time in it without ventilation.

Plenty to think about! keep us updated.

Russell
How many windmills do I have to build to become a windmillologist?

JMaris

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Re: Greenhouse anyone?
« Reply #34 on: May 17, 2010, 06:26:17 PM »
We want to build a 20x50. We live in west texas and the temps range from high of about 100-110 F in the summer and as low as 15F on the coldest winter nights. Given, we get a lot more heat than cool. I am going to put a "swamp cooler" in on one end and have vents and fans on the other end during the summer. The winds out here do get fairly bad during certain times of the year. I wonder if aluminum coated steel tubing (muffler shop tubing) would work... or would it be to weak?  

DanG

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Re: Greenhouse anyone?
« Reply #35 on: May 17, 2010, 09:33:32 PM »
The larger diameter the tube is the stiffer it gets.

For cooling there are also shade - reflector arrangements to cut back on peak hours solar heating.

http://tinyurl.com/2g8htxw <--- twin wall polycarbonate panels 4 & 6 foot wide on supposed closeout.

If you live within a days drive of Cedar Rapids Iowa those panels might be a viable solution - they sell a lot of them but freight shipping and crating is killer. I've been daydreaming of projects with them for years.
« Last Edit: May 17, 2010, 09:35:28 PM by DanG »

frackers

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Re: Greenhouse anyone?
« Reply #36 on: May 18, 2010, 04:53:51 AM »
So what do you guys think about using some thick wall PVC for the frame rather than metal? I was thinking like 1&1/2" or 2"id schedule 40. That would be a lot cheaper and easier to use than steel.

4 by 1 timber - I reckon you could park a truck on mine since just a single section will take my weight (about 190lb) . Rigid enough with 5-6 sections that I can pick one up with the tractor (bucket at one end, timber post on the 3 point rear link) and move it about on the garden (200' from construction site to veg plot!!).

I've costed out a shade house of 14' wide by 17' long at less than NZ$300 using H4 pressure treated timber (ground contact), all the nails and screws and including the shadecloth (half a 50m roll). I'm sure you could get the timber cheaper by looking round or stripping down old pallets. It takes me a full 8 hour day to cut all the timber and nail it up - if I had some help I could probably halve that time.
Robin Down Under (Or Are You Up Over)

SteveCH

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Re: Greenhouse anyone?
« Reply #37 on: May 18, 2010, 12:43:05 PM »
We want to build a 20x50. We live in west texas and the temps range from high of about 100-110 F in the summer and as low as 15F on the coldest winter nights. Given, we get a lot more heat than cool. I am going to put a "swamp cooler" in on one end and have vents and fans on the other end during the summer. The winds out here do get fairly bad during certain times of the year. I wonder if aluminum coated steel tubing (muffler shop tubing) would work... or would it be to weak?  

Swamp cooler is good, and you'll need a very large one. Well, you may need two very large ones. Our greenhouse is 12 x 23, outside temp's top out at mid-90s, and our 4,000 CFM swamp cooler barely keeps it liveable for the plants, takes it down to about 80 F. or a little higher on the hottest days. You will likely want to plan for some shading material you can roll up out of the way. You will need shading even with the cooler. Our shading is on the inside due to very high winds now and then, and you may need to do the same. Shades cool better outside, but they are then subject to wind damage and also can flap hard against the structure and damage it.

[Is this sounding more complicated all the time? It will be worth it.]
« Last Edit: May 18, 2010, 12:45:34 PM by SteveCH »

JMaris

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Re: Greenhouse anyone?
« Reply #38 on: May 18, 2010, 09:10:25 PM »
It sounds more and more complicated every day. As much fruits and veggies as we eat, I know it will be worth it! Not to mention it is something we have wanted to do since we married.

JLB FAB

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Re: Greenhouse anyone?
« Reply #39 on: May 18, 2010, 09:57:05 PM »
DONT use pvc for a frame a chemical reaction between the pvc and plastic covering will destroy it in the first year

frackers

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Re: Greenhouse anyone?
« Reply #40 on: May 19, 2010, 05:15:16 AM »
It sounds more and more complicated every day. As much fruits and veggies as we eat, I know it will be worth it! Not to mention it is something we have wanted to do since we married.
No pix of the inside, but this is a small part of what came out of it...
Robin Down Under (Or Are You Up Over)

frackers

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Re: Greenhouse anyone?
« Reply #41 on: May 19, 2010, 05:17:36 AM »
Having just posted my first picture to the new board and seeing it totally out of the context I was aiming for, can someone give a clue as to how I preview attaching an image? The text was supposed to be below the picture...

Cheers
Robin Down Under (Or Are You Up Over)

TomW

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Re: Greenhouse anyone?
« Reply #42 on: May 19, 2010, 05:35:25 AM »
can someone give a clue as to how I preview attaching an image? The text was supposed to be below the picture...

Cheers


Right now, you can't.  >:(

We have some plans to make that possible.

Otherwise you can use web hosted photos "inline" like you want but that is a bit more effort. This has been covered elsewhere so I don't want to divert this thread explaining it here.

Tom
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JMaris

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Re: Greenhouse anyone?
« Reply #43 on: May 19, 2010, 08:54:52 AM »
I shouldn't get a chemical reaction using hot spot tape right?

JMaris

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Re: Greenhouse anyone?
« Reply #44 on: May 23, 2010, 10:12:17 PM »
So I scored a ton (probably literally) of pipe and angle iron yesterday.  It is mostly structural pipe and angle iron but there are some 20 or 30 foot long sections of galvanized pipe. Im not sure how many there are or what condition they are in. I will take inventory as I unload all of it this week and get a better knowledge of what I got.  Hopefully there will be enough of the galvanized to build my greenhouse. If not, at least it will be enough to get a good start on it. Good news is that thus far all that it has cost me so far is the 2 hours it took me to load it all up on the trailer!

wooferhound

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Re: Greenhouse anyone?
« Reply #45 on: May 31, 2010, 06:45:04 PM »
People on here are talking bad about PVC pipe green houses
I have built about 5 of them and except for replacing the plastic every 3 years or so they have worked wonderfully
These were built in Alabama where the weather is generally mild.
we would use clear plastic in the winter then Black Shade Netting in the summer like this picture shows
« Last Edit: January 25, 2011, 11:15:18 PM by kurt »

JMaris

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Re: Greenhouse anyone?
« Reply #46 on: May 31, 2010, 07:52:34 PM »
Looks like you used 2" schedule 40? How long were the joints of pvc you used?  Looks like you are having to duck to walk through... What is the height at the peak? Im not sure if the pvc will withstand the west texas wind we get out here. Which is why I am glad I have some galvanized pipe. I don't remember how many I have though. I will count them tomorrow. If I don't have enough to make it as long as I want to, I will alternate between pipe and pvc. I am hoping to have the greenhouse built before summer ends. We have been ridiculously busy getting our house setup. I just poured the slab for our water well house today and we are still waiting on the power company to get us hooked up... So needless to say the greenhouse isn't quite at the top of the list, but it is close!
« Last Edit: May 31, 2010, 08:12:57 PM by JMaris »

JMaris

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Re: Greenhouse anyone?
« Reply #47 on: June 02, 2010, 09:06:54 PM »
Well, it looks like I have 3 pieces of about 30ft galvanized and then some shorter pieces. I have 2 more long ones, but the finish on them isn't the best. I need to clean them up and see if it is just junk on top of the finnish or if the finnish is damaged. I figure I can alternate galvanized pvc galvanized pvc etc... or galvanized pvc pvc galvanized pvc pvc etc... depending how many of the pieces of galvanized clean up good. How far apart do you guys think I should space the support ribs? I was thinking 6 or 8 feet. What do you guys think?

sbotsford

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Re: Greenhouse anyone?
« Reply #48 on: January 08, 2011, 11:56:12 AM »
I have a small greenhouse, built from an old shed and a raft of used windows.  Roughly 7' x 8'.  With it, I start my plants in the house, then start up the greenhouse on the 1st of april, which is 7 weeks before we usually set out bedding plants.  a 1.5 Kw heater gets me through the cold nights.

This is a good way to start -- see if it's fun.

I want to build two more:  One will be a 'conservatory' attached to the house.  Used as a sun room, and a place to start seedlings.  I also want a 30x60 foot gothic hoop house for production use -- forcing lilies for the spring trade

If you are in a cold climate (We're zone 3) then running a greenhouse in winter isn't reasonable without a bunch of supplemental heat.  If it is well made running it for 8 months a year can be done.

Consider building a greenhouse attached to the south side of your house.  Even if you shut it down for the winter it can provide heat to the house during sunny days.

Build as much water storage as you can into a green house.  This reduces temperature swings. 

Your aisles should be wide enough to move a wheel barrow down them and squeek by it.

A good cheap way to make benches is a double row of barrels (filled with water) and used pallets.  Note that the cracks in the pallets make wonderful places for pests to overwinter.  There is merit in closing the greenhouse up and get the temps as high as possible for a few days at some point each year.  (140F will kill many eggs)

Reaching over 2 feet into a row is hard.  Wall benches should be 2 feet wide, center benches can be 4 feet wide.  With 3 foot aisles this makes for certain magic numbers for width: 

*  Two wall benches + 1 aisle = 7 feet.
*  Two wall benches, 1 center bench + 2 aisles = 14 feet
*  Two wall benches + N center benches + N-1 aisles = (N+1)*4 + (N-1)*3.

Watch kijiji and craigslist.  Sometimes you can get a used greenhouse frame for cheap.

The usual problem with a greenhouse is NOT heating it, but cooling it.  In summer you need an air exchange a MINUTE to keep from cooking it.
This can be done with high speed fans, or roll up sides, or complicated roof mechanisms.  In the southern US they often remove the plastic for the summer.

In your research google "high tunnel"  Cornell has a good set of resources for it.

Building an attached shed to the green house is a good idea.  This is where you do your potting, keep the watering hose, all those bits.  In the trade it's referred to as a head house, as it was usually on the north end of a bunch of N/S running greenhouses.

If you want an interesting take on low energy cold climate greenhouses google solaroof  (Note only 1 r) This is a technique using soap bubbles as insulation/sun shade between two layers of plastic.

If the greenhouse is seasonal then being able to separate it into chunks has merit.  In early spring when starting seeds, you only need a small chunk at one end that is kept warm.  As plants are moved to larger and larger pots, the partition is moved down.  In this way a moderate heater can heat a small area during very cold times, and a larger area in not so cold times.

On a sunny day, a greenhouse needs an air change every 10 minutes just to provide CO2 for the plants. This varies with the amount of green in the house.  In winter you want makeup air to be well mixed with the existing air before it touches a leaf.  In commercial houses this is done with a 2' diameter poly plastic tube with  small (about 1 cm) holes every few feet.  The tube is hung from the ceiling.

If you are clever, you can reduce outside air by using a compost heap for your CO2 source.  You have to watch the C:N ratio as too much N and the heap will produce ammonia gas which is tough on your plants.

I've also heard of using chickens as your CO2 source.  Chicken crap has a big ammonia problem.

If you get a used greenhouse, take a LOT pictures of it.  Bring a pad of paper and make signs:  "Top end connector"  "Mid wall perlon"

As you dissasemble, take another set of pictures of the piece, and the bolts.  Not all the bolts are the same.  Use up the 2.25" ones where the 2" ones should have gone will leave you short later.  It's a good idea to put the bolts back into the connectors.

Do some careful measuring.  Some greenhouses are sent with all holes in place, some you have to drill on site, some are a mix.  If the holes are drilled on site, they will vary in position.  E.g. if one rib is an inch out of line, it's holes will be an inch out of line.  This will make reassembly tricky.
If the holes are predrilled, you move the pieces to meet.  If they are site drilled, you can mark every piece with location and hope, or you can resign yourself to drilling new holes.   Drilling new holes isn't usually a big issue. 

If you live in a snowy climate get a gothic arch.  Round tops collect snow. 

Do your homework:  Research the brand, and check the rated snow load.  Snow will usually slide off a gothic arch roof in a few sunny days.   If you ever get 2 feet of wet snow at once, you need a roof that will support that.  A cheap greenhouse will have a 10-15 lbs/sq foot load capacity.  Good ones run about 40-50 -- same as a house.  You can compensate in part for this by putting the ribs on closer spacing.

Larger greenhouses are easier to control for temperature.  So are taller ones.

sbotsford

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Re: Greenhouse anyone?
« Reply #49 on: January 08, 2011, 12:01:47 PM »
DONT use pvc for a frame a chemical reaction between the pvc and plastic covering will destroy it in the first year

PVC is also one of the most evil compounds made.  Really hard to dispose of in a green way. 
If you must used PVC, paint it with latex paint to inhibit the reaction between the outgassing plasticisers and the poly. 
If you are in love with plastic, use ABS (drain pipe) instead.  Paint it white.


For the strength, metal isn't that much more expensive.  The steel conduit used for the top of chain link fence is a good place to start -- it comes in 30 foot chunks.  There are benders on the web to make your arches.




dnix71

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Re: Greenhouse anyone?
« Reply #50 on: January 08, 2011, 08:27:49 PM »
Frackers here's your pic. A lot of the pix in this thread are not displaying inline I think because they are 640x480. I think the limit is 600x480 but it doesn't say anything below except 150kb limit. I used the GIMP to resize yours to 600x450 at 90%. The GIMP is free and comes in handy for this. I own a Mac but don't want to pay for Photoshop. The GIMP does more than I will ever need. Inkscape does vector graphics for free if you need that.

http://www.gimp.org/
http://inkscape.org/


offgridgirl

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Re: Greenhouse anyone?
« Reply #51 on: March 27, 2011, 09:23:45 PM »
Yes we have both.  One is attached to the dome and one is outside and portable.
I will have to take some pictures as I can't find any in my album at the moment.
There is a picture on my website, if you want to look ;)
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ruddycrazy

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Re: Greenhouse anyone?
« Reply #52 on: April 17, 2011, 12:17:32 AM »
I made this greenhouse out of 4" fence posts and covered it with 40% green shadecloth. The concrete goes right around and at the rear it's pretty high and the inside was first covered in black plastic then 5 ton of 10mm rocks were placed in. At the rear is a sump where excess water flows into and when the drum is full it is filtered then sprayed back through the micro sprays. My wife is pretty happy with it as she can grow her herbs all year round and not worry about heat or frost.

Cheers Bryan

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DamonHD

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Re: Greenhouse anyone?
« Reply #53 on: April 17, 2011, 02:44:07 AM »
Looks good!  That's about the size of my whole garden.

Rgds

Damon