What sort of heat reduction will the netting give compared to poly sheeting .
If I paint my glasshouse in white sun block , the heat reduction it tremendous .
Most times I've used it it has delayed the crops with in by three or more weeks & this is on plants that have started growing in the second potto=ing up pots from a thermostaticaly heated UV l( LED BULB ) bed
Last year here in South Wales none of my tomatoes managed to ripen till I washed the shade wash off .
You can make end windows well hinged at the top out of netting & / or poly sheet & use adapted automatic greenhouse window vent opener fittings @ approx £15 per opener device including arms & mountings
Thanks clodhopper: your points above are food for thought.
I would add, however, that I'm not thinking to bring plants on to maturity (or fruiting) under "cover". What I'm looking to achieve is a low-attendance benign environment for seedlings to take-off before selling as seasonal cell-grown seedlings (veg), or as seedlings to put out-doors to grow-on for eventual sale as plug or bare-root plants at 2-3 yrs (conifers or broad-leaf). Some, of course, will go outside to be grown-on as Xmas trees "in the field".
I did find a piece on netting acting as a heat-sink, but is was in combination with a glass or plastic covering and not in the UK (Australia I recall - of course that would be a whole different climate!) - I seem to have lost the link though.