building a greenhouse--need advice!!

[Patch of Heaven Farm]

Hi,


I am planning a greenhouse and need help with making sure it will actually be worth while!
I have a structure that was intended for a small horse stall for the kids ponies but we changed our mind and built run-in shelters instead in the fields. So I have a framed building 12 x 14 and thought about turning it into a greenhouse. We haven't put a roof on it yet and the sides are just framed. I thought I could get some concrete poured for the floor and build shelves and such. It is close to the chickens and my garden. It is facing south and is in full sun all day. My question is what should I put on the roof and sides? I live in southern Ms and I am in zone 8. We rarely have freezing temps (but it did snow 8 inches here in Dec) but we do have a few days of pretty cold weather. I would like to grow things in the winter and for starting seeds in the spring. Any help and advice would be appreciated. I want to do this cheaply as possible but something that will last awhile. I thought about putting plastic around the sides and some fiberglass panels on the roof. Please help!!

Also anyone have any good ideas on making a worm bed? I would like to make one close to the greenhouse. :watering


Thanks, Jessica

 

[patandchickens]

I have a structure that was intended for a small horse stall for the kids ponies but we changed our mind and built run-in shelters instead in the fields.

Just wanted to say good for you! Much better way for them to live

I thought I could get some concrete poured for the floor and build shelves and such.

I am not sure how worthwhile it would be to spend your money on concrete as opposed to other places in the structure. Plenty of people have tamped gravel floors, with some pavers atop it in the aisle if you prefer, and that would be cheaper. You will probably *need* to budget for some automatic openers at *least*, possibly a thermostat-controlled fan, to keep it from getting too hot in there during the day. And it may be worth spending more rather than less on the material for roof/sides, to get something that will work more satisfactorily and last longer.

My question is what should I put on the roof and sides? I live in southern Ms and I am in zone 8. We rarely have freezing temps (but it did snow 8 inches here in Dec) but we do have a few days of pretty cold weather.

It depends how much money you want to sink into this You can get greenhouse plastic that just clips or staples over the structure, but it mostly only lasts a few years and is a bit vulnerable to wind and hail damage. Glass or plexiglass or Suntuf would be your other usual choices, depending on budget. (Further north I'd recommend double-walled acrylic greenhouse panels but they're kinda expensive and surely overkill for Mississippi ) Whatever you get, make sure it can stand up to UV and high temperatures (if you are browsing at your local Home Depot and notice the corrugated clear sheets of plastic Palruf, note that the mfr. specifically recommends AGAINST using it for greenhouses, because of not being thermally stable enough and because of offgassing).

To help vs cold snaps, two big things are a) stuff the greenhouse with as much thermal mass as you can, ideally water-filled black-painted metal or thin-walled-plastic containers. It will make the greenhouse warm up more slowly during the day (which is actually a good thing, reduces overheating) and makes it cool off more slowly at night. Also, during a cold snap you can rig curtains inside the greenhouse or little 'tents' over the plants or stick bubblewrap to the inside of the glazing, those things will help too.

I would like to grow things in the winter and for starting seeds in the spring. Any help and advice would be appreciated. I want to do this cheaply as possible but something that will last awhile.

Your limiting factor in what you can grow is usually how cold the greenhouse drops at night. THis can be modified somewhat with shrewd design, lots and lots of thermal mass, and appropriate insulation, but beyond a certain point you can't grow warm-weather things (like tomatoes or orchids) without nighttime heat. I have no idea how this maps onto exact greenhouse design for Mississippi, you might want to talk to others in your area who have greenhouses and can give much more specific advice about that.

Have fun!

Pat

 

[Patch of Heaven Farm]

Thanks Pat for the help!! I have been checking prices for plastic and was thinking of using this for the sides but I didn't think it would work for the roof b/c we have a lot of rain and I figured it would just rip after awhile. Should I put greenhouse panels all the way across or should I alternate with tin or something to keep it from overheating? Not alot of ppl in my area with greenhouses b/c our temps are mild most of the time. But I want to be able to get ahead start in the spring and maybe raise some herbs and citrus trees in containers.


Again thanks for the info!!


Jessica

zone 8 :rainbow-sun

 

[vfem]

Pat is always FULL of the best advice and ideas. I would really listen to her.

 

[Liberty7]

Depending on the size of the greenhouse, if you put down a concrete floor, your property taxes will go UP just like with a backyard shed!

 

[patandchickens]

have been checking prices for plastic and was thinking of using this for the sides but I didn't think it would work for the roof b/c we have a lot of rain and I figured it would just rip after awhile.

The plastic that is like a translucent tarp, definitely a no-no for roofs. The plastic roofing panels like Suntuf however are FINE. (I'm put a translucent white version -- you'd want clear -- on my new chicken runs, and am paying about $50 for a 2x12' panel. It may well be cheaper in the States though)

Should I put greenhouse panels all the way across or should I alternate with tin or something to keep it from overheating? Not alot of ppl in my area with greenhouses b/c our temps are mild most of the time. But I want to be able to get ahead start in the spring and maybe raise some herbs and citrus trees in containers.

If you alternate with soemthing, don't use tin, that will REALLY lead to overheating <g>. I dunno, it depends pretty totally on what you want to grow. If you just want to keep nonflowering things alive over the winter and raise, like, lettuce, it is quite possible you may be able to get away with part of the roof opaque. OTOH I really don't know, and if you do that it may be awfully hard to convert back to all-clear-plastic in future.

If you want part-opaque roof, make the sunward slope of the roof all-Suntuf (or whatever), and the northward slope of the roof all opaque. (Frankly I would recommend opaque suntuf but plywood with metal roofing or light-colored shingles over it would probably be ok). [it occurs to me I'm assuming the long axis of the building is east-west. If not, then make the southern half of the roof, both slopes of it, clear -- the northern half of the roof both slopes opaque.

You'd have to sit down and see whether that'd actually save you any money though. It might not be so much of a difference as you might think!

REally you will be much, much better off if you can find people running greenhouses in your area. They will be able to guesstimate how much your structure will cool off at night, how much it will tend to overheat during the day (hence how much ventilation you need to build in -- I will warn you that auto openers, which are $50 a pop already, are quite often insufficient and you may need to move up to a thermostatically-controlled vent fan, which starts in the several hundred dollar range), etc etc.

Good luck, have fun,

Pat, who grew up in a house with an attached greenhouse (orchids mostly) and would really like one (NOT heated, just very well designed in a passive solar way, for lettuces and such) but it's not likely to happen anytime soon

 

[vfem]

Here's the greenhouse we're planning on building:

http://www.buildeazy.com/greenhouse.html#1


Here's some samples of one's people made from that plan, including changes:

http://www.buildeazy.com/photo_greenhouse_side.gif

http://www.buildeazy.com/photo_greenhouse_ken.gif

My favorite is the second one, I think that is what we are going to do with a peagravel and flagstone walk inside. Makes it a mobile piece so I don't have to report it being built.

http://www.buildeazy.com/photo_greenhouse_swingseat_alex.html

(That site also has lots of other plans, for chicken coops, wells, benches, picnic tables, gazebo....ect! We made the garden benches so far, very inexpensive and easy plans.)

 

[patandchickens]

Oh, btw, you will want to run extra diagonal bracing on the shed walls and ceiling. Normally the plywood or metal walls themselves would give some degree of rigidity but without 'em you will want to add 'artificial' diagonal braces (or plywood gussets at corners, but they're not as strong) to reduce the extent to which the structure gets twisted all out of shape in the wind.

(Just crossed my mind b/c I was out working on the sussexes' new roofed run, essentially a wall-less shed, and thinking about exactly how to brace *that* )

Pat

 

[Patch of Heaven Farm]

Thanks for all the great info!! I am going to check around and see if I can find someone near with a greenhouse. My grandmother had a greenhouse when I was a child and she had all fiberglass(seemed like it anyway) like panels for the roof and sides with gravel for the floor.The panels were green and clear alternated. She seemed to grow a pretty big garden and always had lots of flowers but I can't remember exactly how well the GH worked.

Thanks again!!

Jessica

P.S. I probally will finish the Gh this summer to get ready for fall/winter since it is to late for this spring. So plenty of time to get the materials and plan for it!!! :coolsun

 

[j.luetkemeyer]

Another option would be to put the money into cold frames instead and use the frame for something else. Cold frames work pretty good where I'm at in zone 5. I would think they would be great for your area.