On Fri, 18 Jun 2010 18:29:31 +0000, Jake_Darvall wrote:


What I'm worried about is heat. Because this side of the shed faces
north, and during summer in particular there's a lot of heat reflected.
scorching at times.

You could always "face" the side of the shed with a few. Or fasten a bit
of shade cloth to the shed and/or cover the plants.

Would I be wasting my time building boxes ?

Define waste. At the worst, you'll have an idea of what doesn't work.
OTOH, microclimates can produce some interesting results.