On 22/06/2013 21:06, Howzit_China wrote:
Hi,
Looking for advice on a greenhouse I am looking to build in the sunniest
(relative) spot in my London garden.
My garden is West facing, the patch is South facing and gets sun from
12:30 to 18:00 (5.5 hours). Last summer I grew cherry tomatoes and
courgettes with fair success in this patch (birds got most of the cherry
toms tbh). I got a bunch or large tomatoes which didn't ripen in time
before the plants died at the end of the season (I didn't realise you
could ripen them indoors).
I want to build a greenhouse on this spot to increase my success rate
with tomatoes and other sun-lovers like peppers, cucumbers, squash and
pumpkin.
Originally I was going to buy a 4 x 6 foot aluminium greenhouse as the
space is awkwardly shaped and this is all I could find that would fit,
but then I thought if I design and build my own I could make better use
of the space and have a bigger greenhouse for the same money.
It's going to consist of a brick foundation (neighbours old driveway),
wooden frame (scrap liberated from skips), kitchen flooring for floor
(have this lying around) and a polycarbonate surface which I will need
to source. The whole structure will be covered in polycarbonate as I
don't want any wood exposed to the elements. See CAD drawing attached
(dimensions in mm). I've got my brother visiting in Sept and he has some
carpentry skills so planning to start work when he's over.
What I couldn't figure out how to get across in the drawing with my
limited CAD skills is the panels A and B, I want the poly carbonate
sheet at B to be fixed in place, and A to open upwards on hinges, like a
grow box, except a 1.6 meter high grow box = ). This should give me good
access to all the plants as the space behind B will be quite large for
me to be able to duck under.
So questions:
1. What thickness polycarbonate and how many chambers is usual for
greenhouses?
Depends on your budget, but twin-walled is sufficient for a greenhouse.
Probably 6mm would be best.
2. Does the pitch of the roof look OK? Is this important?
Can't tell from the diagram. Why does it need to be pitched anyway?
3. Will leaving the door open (A) occasionally be enough for ventilation
purposes?
No. You will need a vent near the ground on the right-hand side (near
where the "B" is on the diagram). That will give you airflow through the
greenhouse. Without it the RHS will get really hot in full sun.
4. Does the design look practical?
Is there no way you can increase the height? I think you'll find that
1500mm will leave you a bit cramped and hot, especially if it is a very
sunny day
5. Is it worth the effort considering limited access to sunlight?
Only you can really decide that, but as you've grown things successfully
before, it should be ok. But you might find that it's cheaper in the
long run to buy one of those polythene/PVC-covered greenhouses and
replace the sheeting every couple of years. I mean the sort of things
shown he
http://www.robertdyas.co.uk/?attribu...E%20DESCENDING
That might also give you a relatively cheap idea of whether or not it's
worth bothering constructing the polycarbonate-covered greenhouse you
are thinking about.
--
Jeff