From doug@conch.aa.msen.com Tue Jul 30 21:33:55 1996
To: Aaron Hicks <ahicks@nmt.edu>
Subject: Re: Doug!
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Aaron --

here is #3

ll1 - Site Prep - (posted 7/24)
ll2 - Framing   - (posted 7/30)
ll3 - Ventilation

This is the third is a series of messages about the lessons I have learned on
my first greenhouse.

Once the frame was up in Late October, I had to cover the openings for the
vents and the fan with poly, they had not arrived yet. This meant that I did
not have any effective way to vent the greenhouse, except to leave the door
open or to remove one of the pieces of poly.

It was 6 weeks later that they arrived. In mid-November. By then the fan was
not a useful thing to put in, so I rolled the crate into the greenhouse for
spring installation and used if for a potting bench all winter {-:

The vent on the other hand were badly needed. Not for the vent purpose, but
rather because I had had to replace the poly over the vent holes twice.
My vents are 30 inches by 60 inches each. I expected that they would (as shown
in the one and only photo I had) install from the outside. They did not,
they went in from the inside. They were also a different size than specified
The rough openings I had left were 2 inches too wide and 1-1/4 inches too
tall. This meant shimming the holes. The 2 inch problem was easy to deal
with, I used 1 inch plywood scrap, that I picked up at the lumberyard for free,
to shim, left and right. But the 1 -1/4 was 3/8 too small for a 2x4, so I
resorted to a power planer to reduce a 2x4 to a 5/4 x 4. It was a very cold day
and my hands were very very cold. At least the poly could stay in place until
the vents were in (it on the outside and the vents going in from the inside).

The very thin aluminum frames of the vents bent every way known to man. I
finally put the shims directly on the sides of the vents to get them into the
wall. I then used screws to attach them. I no more than got them in place, when
I realized I had a problem. They would leak cold air all over the place.

Back to the lumberyard.

Two sheets of blue foam board and I was in business. I cut a piece for each
vent and put them on the outside of the vents. I then used duct tape to
seal them in place. It was a wet day, so I had to redo it a couple of times
during the winter. Since it was so cold when I installed them, the blue
board popped out of the vent frames as soon as the weather hit 55 for the
first time. I spent 3 weeks checking the fit each night before bed, to
ensure that the spring frost did not get to the orchids.

Since I was so late in getting them in. I did not get the insect net installed
on the inside. I missed the first several weeks of small insects and lost
a number of orchids (and small seedling plants) to spider mites. I run an
organic greenhouse (I am allergic to most pesticides) so I am still fighting
this problem with bacteria and wasps, and other counter insects.

I was very busy in the early spring, so the fan lay in its crate until the
first day the inside of the greenhouse hit 110 degrees (f). This did not
help the plants either. I fogged the place and started un-piling all the
stuff that had grown around the fan crate. I rolled it out of the greenhouse
and started to uncrate it. Once that was done. I tried to lift just the
fan. No go, I had to get help. Two teens down the road were home from
school, so I rented them as cranes for a couple of hours. The fan did
not fit in its hole, surprise, the hole was too small, and too weak for
the weight of the fan. I ended up spending a couple of hours redoing the
hole for the fan and bracing the end wall. With my human cranes we lifted and
set the fan in place. Then came the fun part, no instructions on how to
wire the fan. I finally found a college text on motors and figured out
how to set it for 110v. It is no fun climbing inside a motor, so try to
get your fans prewired, for the voltage you need. Acme will do it, if
it is specified on the order form for free, my salesman did not bother.

The fan louvers did not fit over the fan in a 2x4 frame wall, it turned
out that the spec on the fan called for being installed in a 2x8 framed
wall. So I improvised with a 2x6 and framed the fan in after it was installed
from the outside. Turns out that was a good thing, because the salesman
ordered the cover for the fan based on the blade diameter of the fan
and the overall dimensions of the louvers. That meant that I had to
make the opening smaller than the fan diameter to be able to attach the
louvers to the fan. The only part that went well that day was installing
the inside cage for the fan. It went up in about 20 minutes, all the
holes matched and the whole thing just went together. Finally something
worked.

I had ordered a hydrofan mid-summer and installed it. I intended to use
it to automatically fog the greenhouse when needed and provide air movement.
Well, the humidistat did not work on arrival, and on two tries I still do
not have one that works. So the fog is all manual. The air movement is
wonderful. I made the mistake of hanging a new spider plant in the
direct path of the hydrofan and within a week all the spiders were blown
off the stems. It (the spider plant) has recovered, but I have 20 more
pots of spider plant, as a result of the misplacement of the plant.

I have a new vent and heat control system, in the box, that came a couple
of weeks ago and I plan to install it this late august, for now
the Orchids (what remains of them) are on the front porch, with a box
fan blowing accross them, the same way I had it set-up two years ago.
Then again I have about the same number of plants as two years ago.

Needless to say I learned a few things -

1) get real drawings from the manufacturer in advance for all equipment
to be installed. Ensure the dimensions are correct. Talk to an engineer
about rough opening sizes (how big the hole in the wall should be).

2) Understand which side things install from.

3) Set delivery dates and penalties, 11 months later the vendor for my
greenhouse still owes me pieces.

4) Pretest all controls and understand how they work and where to install
them.

5) Get air leaks under control early. I spent about $100 a month to
heat the greenhouse (20 x50) once I had the air leaks covered. Do not
make it too tight or the air will not be good for the plants.

6) Ensure you know how the wind blows and make the ventilation work with
the wind. Do not try to buck the wind with your exhaust fan, mine spins
backwards sometimes.

7) If you have intermediate doors, know how you are going to vent thru
them. They will not stay open on their own.

8) Keep spare blueboard and poly around, you can rig air deflectors to get
air where you need it with them, cheaply.

9) Be aware of what water and humidity do to electrical components and
only buy equipment rated for use in a wet environment.

10) Remember there is a 8 to 12 week lead on most ventilation equipment.
You are too late for this year already.

11) Orchids like moving air, the one thing that I did right was to over
buy in fan and vent sizes.

cheers

--=doug=--


Ban Di-hydrogen-monoxide!