HI all,

I am considering making (er...commissioning my husband to make) a mini
greenhouse. I would like a small home to nuture cuttings outside,
without having to invest in special lights, heating units, etc...
Here is my general plan for the greenhouse, can anyone comment if they
see anything wrong with this:

I am thinking of designing a small box, roughly 3 feet wide and long (I
want to start out small).
I'm thinking it should be 2 feet deep (Is this enough???)
The sides of the house will be made of wood, the top/roof will
(ideally) be glass or thick clear plastic (if we can't find cheap enough
glass) fitted into a wood frame.
The bottom will be wood, maybe lined with one of those rubber web
looking doormats for better drainage.
I have seen some mini greenhouses that have a slanted roof--is this to
conduct sun/heat or could I go with a flat roof?
If I use a wood greenhouse w/ glass or plastic roof, could it be used
year round? Would I have to propagate early spring? Would I need any
additional heating if the temps dropped, and at what temp would I need this?
Will wood sides make a difference if I keep the plants in the center,
not too close to the siding that they are shielded from light?

Thanks for any input you all have!
Heidi
Raleigh, NC.
US
Zone 7b

Heidi wrote in message ...
HI all,

I am considering making (er...commissioning my husband to make) a mini
greenhouse. I would like a small home to nuture cuttings outside,
without having to invest in special lights, heating units, etc...
Here is my general plan for the greenhouse, can anyone comment if they
see anything wrong with this:

I am thinking of designing a small box, roughly 3 feet wide and long (I
want to start out small).

I have a 3X4X2 clear box that I can lean onto the south side of my
home. If, like me, you leave gaps for air to circulate, it will get
cold at night. If you don't, the plants will eat up all the CO2 in a
matter of hours and won't grow.
You can get some CO2 if you put manure at the bottom and put the pots
on top. Typically half the carbon in a compost pile ends up as CO2, so
you can get an idea how much you will get. My one also got very hot
during the day (100+).

Also, that box was way too small. I needed something that can take six
seedlings trays at least, on top of the six that I keep inside the
house. In fact, I need a real greenhouse, however small, with proper
ventilation.

I'm thinking it should be 2 feet deep (Is this enough???)
The sides of the house will be made of wood, the top/roof will
(ideally) be glass or thick clear plastic (if we can't find cheap enough
glass) fitted into a wood frame.
The bottom will be wood, maybe lined with one of those rubber web
looking doormats for better drainage.
I have seen some mini greenhouses that have a slanted roof--is this to
conduct sun/heat or could I go with a flat roof?
If I use a wood greenhouse w/ glass or plastic roof, could it be used
year round? Would I have to propagate early spring? Would I need any
additional heating if the temps dropped, and at what temp would I need this?
Will wood sides make a difference if I keep the plants in the center,
not too close to the siding that they are shielded from light?

Thanks for any input you all have!
Heidi
Raleigh, NC.
US
Zone 7b

On Thu, 07 Aug 2003 12:41:20 GMT, Heidi wrote:

I would like a small home to nuture cuttings outside,
without having to invest in special lights, heating units, etc...

I am thinking of designing a small box, roughly 3 feet wide and long (I
want to start out small).

I just made 4 cold frames in the past month with some old wood lying
around the garage. Here is a picture of the two larger ones, with 30
degree angles (when I first started I hadn't remembered the proper
angle equations, but I knew the 30-60-90 rule).

http://home.ptd.net/~vstevans/Jun27_01.jpg

I'm thinking it should be 2 feet deep (Is this enough???)

Yes. Too deep and all the heat will be UP. Heat rises, so you want
to make it as shallow as possible while still leaving room for plants
and dirt. Mine are 1 foot deep at the shallowest spot in front.

I have seen some mini greenhouses that have a slanted roof--is this to
conduct sun/heat or could I go with a flat roof?

25 degrees is a proper angle...it provides maximum amount of sun for
the winter months. There are trade-offs. A slanted roof captures
more sun, but you lose cubic space inside the cold frame as the roof
is slanted steeper and steeper. The heat also gets trapped higher up
in a slanted cold frame, which is sort-of good on warmer days (keeps
plants from roasting).

Making a diagram is easy when using the proper equations. Remember, a
slanted-top cold frame is (from the side) a box on top of a right
triangle. To measure without requiring a protractor, use the
following equations:

To obtain the height with an angle of 25 degrees : Sin25 = opposite /
hypotenuse (hypotenuse = lenth of the glass top). Then add the
height of the BOX part below the triangle. With the hypotenuse length
(glass top) and the angle you desire (in this case, 25 degrees), you
can easily figure out the other two lengths.

The next is the length of the greenhouse, which instead of SINE is
COSINE, so cos25 = adjacent / hypotenuse. This will give you the
adjacent, or length of the cold frame. Now you can cut out the sides
and rear end.

If I use a wood greenhouse w/ glass or plastic roof, could it be used
year round? Would I have to propagate early spring? Would I need any
additional heating if the temps dropped, and at what temp would I need this?
Will wood sides make a difference if I keep the plants in the center,
not too close to the siding that they are shielded from light?

Cooler-weather plants would be a wise decision in a non-heated cold
frame. Choose wisely.

You can add heating coils to the bottom of the cold frame. Then it
becomes a hot-bed. Wood is a good material to use, but use 1 inch or
thicker for better insulation. I don't understand the shielded from
light part.

Just like in growing seasons, deer and other critters could outright
destroy everything. Old starving "Bambi" and his 25 herd-friends
come along in January, they see greens and lettuce inside this thing,
tasty food they haven't seen outdoors for months, and will put a
couple hoofs right through that pretty glass cover of yours to get to
it. Protect your cold frame appropriately.

Dan

In article , wrote:

HI all,

I am considering making (er...commissioning my husband to make) a mini
greenhouse. I would like a small home to nuture cuttings outside,
without having to invest in special lights, heating units, etc...
Here is my general plan for the greenhouse, can anyone comment if they
see anything wrong with this:

Do a web search for "cold frame." And go to the library -- see if they
have Eliot Coleman's book, "Four Season Harvest." He's way into cold
frames. (Any good gardening book will have something on cold frames.)

They're cool, handy little units, and a really good project for you to learn
how to build your own garden gidgits on. Commission your DH to teach you
how to use a tape measure, a pencil, a handsaw, a t-square and a hammer.
(You can advance to Skilsaw later.) Help him build the first cold frame, then
build the others yourself. (You *will* want more than one, trust me.)
If you paint the inside walls white, it'll reflect light to your cuttings.

Don't put a floor in it. Find a used window somewhere for between cheap
and free. You'll want the top to slant, to take advantage of lower sun angles
early in the spring. If you're a good scrounge, you can find the lumber you
need for cheap/free. You might have to buy the hinges at the hardware store,
and the nails. (Use galvanized nails, so they won't bleed rust when they get
wet. Or use screws and a screwgun instead of nails.)

My DH and I just built a 7' wide x 12' long x 9' tall lean-to greenhouse with
a reinforced visqueen cover, for free. We used lumber, hardware and visqueen
we had laying around. It took about 4 hours total, at a *very* laid-back pace.
( He played with the dog while I came up with the dimensions I wanted. I
cleaned
the woodshop while he was kicking through the lumber pile, talking to himself.)

The old trick of burying fresh horse or cow manure under soil, in the bottom of
the cold frame works. The manure produces heat as it decomposes and heats
the cold frame. Any horse owner would be more than happy to give you all of
the road apples you want.

Have fun with your project : )

Jan

Thanks for the advice! I will put your tips to work this weekend, and
now that I know what I want is called a cold frame, I can find out even
more info!

Thanks again!
Heidi




Jan Flora wrote:

In article , wrote:



HI all,

I am considering making (er...commissioning my husband to make) a mini
greenhouse. I would like a small home to nuture cuttings outside,
without having to invest in special lights, heating units, etc...
Here is my general plan for the greenhouse, can anyone comment if they
see anything wrong with this:



Do a web search for "cold frame." And go to the library -- see if they
have Eliot Coleman's book, "Four Season Harvest." He's way into cold
frames. (Any good gardening book will have something on cold frames.)

They're cool, handy little units, and a really good project for you to learn
how to build your own garden gidgits on. Commission your DH to teach you
how to use a tape measure, a pencil, a handsaw, a t-square and a hammer.
(You can advance to Skilsaw later.) Help him build the first cold frame, then
build the others yourself. (You *will* want more than one, trust me.)
If you paint the inside walls white, it'll reflect light to your cuttings.

Don't put a floor in it. Find a used window somewhere for between cheap
and free. You'll want the top to slant, to take advantage of lower sun angles
early in the spring. If you're a good scrounge, you can find the lumber you
need for cheap/free. You might have to buy the hinges at the hardware store,
and the nails. (Use galvanized nails, so they won't bleed rust when they get
wet. Or use screws and a screwgun instead of nails.)

My DH and I just built a 7' wide x 12' long x 9' tall lean-to greenhouse with
a reinforced visqueen cover, for free. We used lumber, hardware and visqueen
we had laying around. It took about 4 hours total, at a *very* laid-back pace.
( He played with the dog while I came up with the dimensions I wanted. I
cleaned
the woodshop while he was kicking through the lumber pile, talking to himself.)

The old trick of burying fresh horse or cow manure under soil, in the bottom of
the cold frame works. The manure produces heat as it decomposes and heats
the cold frame. Any horse owner would be more than happy to give you all of
the road apples you want.

Have fun with your project : )

Jan

What you propose seems to be a "Cold frame"

What ever size it will be to small. Why not lay out a few seed trays and
pots that you think you want to use in it and see how many fit.
The idea of a sloping roof/top is
A/ to let water run off, and
B/ to catch more sunlight in the winter when the sun is at a lower angle.
I doubt if you will make it airtight but ventilate as needed in daytime,
and remember you can shade it from outside to keep some of the heat away,
and in the winter you can always cover the outside with sacking or something
to keep extra cold out.


David Hill
Abacus nurseries
www.abacus-nurseries.co.uk