Greenhouses

 

I'm thinking about getting a greenhouse this year to extend my season (I
live in Massachusetts). Last fall someone on this group suggested I try a
popup greenhouse because they are very cheap (under $150, some as low as
$50), rather then make any kind of major investment. Does any one have
any experience with them? There also seems to be a class of greenhouses
that are a step up, around $600-$700. The cheap ones are basically
plastic tents, the mid priced ones are aluminum and polycarbonate. I'd
like your opinions on both types. In my heart of hearts I've always
wanted a proper glass Victorian greenhouse, but that's real money so I
want to see if a greenhouse is helpful to me before I make that kind of
investment.

 



I bought a $110 plastic greenhouse from Walmart.  It was easy to assemble.
The workmanship was a little shoddy, but nothing drastic--just a zipper
off-kilter, some crooked seams, that sort of thing.

There were two problems I saw, and these might not be problems for you:

1. It didn't stay warm at night.  I'd see seedlings popping up during the
day (when it was VERY hot inside the greenhouse), then they'd die overnight.
If you are going to put some nighttime heating in it, then this probably
wouldn't be an issue for you.

2. The wind completely took it away.  We staked it down all around AND put
concrete cinderblocks around the perimeter of the greenhouse, but on one
windy night the entire thing was pulled up from its stakes and blown into a
tree, where it twisted and broke.  The plastic was ripped, and the metal
bars were bent and sheared clean off at some places.  (A few of the stakes
were still in the ground; the wind had separated the poles at the joints and
lifted them away!)  If you do not have a lot of wind where you live, this
shouldn't be a problem.

I really like the idea of these inexpensive greenhouses, but for me it was a
waste of money.
--S.

 

On Sun, 07 Mar 2010 12:36:25 -0700, Suzanne D. wrote:


Thanks for your feedback. Both of those things are issues, I wondered how
something that was basically a tent could stand up to any kind of wind,
apparently they can't.

 



 Maybe nestled up to a south facing wall with  east and west protected
with a few cider blocks.  As I understand it auto venting device is
really of import or the heat which varies a lot due to no solar mass
fries or freezes your plants.  I's add gallons of water maybe half your
space to try to moderate the temperature swings. Small maybe beautiful
but one has to work harder on your design.

--
   Bill   Garden in shade zone 5 S Jersey USA
<http://www.globalissues.org/article/75/world-military-spending>

 

Bill who putters wrote:

   I like that idea.

   You may wish to look at home made hoop greenhouses. Easiest way is to
drive rebar into the ground, and pop the hoops on the exposed rebar. You
will need to recover every few years, but the material is cheap.

One example:

http://westsidegardener.com/howto/hoophouse.html

   My general advice, curves are strong and resist wind. If you can prop
this against a south facing wall you will cut your heating needs.
Greenhouses lose heat at night, and lots of it. Without added heat,
inside temperature will be the outside temp by morning if not long before.


   As I understand it auto venting device is

Water is one BTU per pound water degree F. Heat loss for single layer is
~ 1 BTU/hr per square foot times the temperature difference. It adds up
to a lot of water as Bill has said. Try Drums. Other materials store
heat, but not as well as water.

  Double or triple wall polycarbonate will cut the heat loss by almost a
half to two thirds.

   I'll retrofit my solar cabana with mylar storms this fall. Clear
mylar degrades in UV so it needs a UV outer barrier.

   I've been using vinyl shower curtain liners. They are very clear and
hold up well, so far.

   Jeff

Small maybe beautiful