The message
from "Martin Sykes" contains
these words:



"Glen Able" wrote in message
...


I still think the mirror has some benefit though - because the area of the
mirror is greater than the area of the greehouse floor, it's getting more
light into the greenhouse. I've drawn a diagram here :
http://www.users.globalnet.co.uk/~sy...reenhouses.jpg

In the standard greenhouse, some light just passes through without going
near the plants.

That doesn't make sense. To grow straight and evenly, plants need
light all around, and that's what they get in a standard GH. The uneven
light in a leanto GH makes seedlings lean to the lighter side, and
necessitates turning the trays or pots.

In the modified one on the right, the roof is asymetrical
and internally mirrored on the side away from the sun so that that light
gets redirected to the plants. I bet it wouldn't be an expensive
modification and might make more of the little light we have. You could also
mirror the vertical side as well. Maybe even tin-foil would do the job?

The sun moves across the sky so doesn't always fall on the mirrors;
when it doesn't, any potential benefit is lost. Meanwhile, the mirrors
constantly reduce light from their dark side.The plants are alternately
fried, and drawn.

:-)

Janet.