Fogging Bar for Greenhouse?

This feels more like an engineering feat rather than a gardening matter but still...

I want to increase the humidity of my greenhouse for my tropical cacti as well as also decrease the temperature in the summer and I feel by incorporating a form of automatic misting that I could do this I've seen so called "Micro Irrigation Systems" which all tend to be around 20m of 4mm piping and a 3/4" tap connector and then hundreds of little drippers for each plant and the odd spray connector which seems a huge faff for the amount of plants I have.

My idea is to attach a length of 1/2" garden hose to the middle of the eaves of my greenhouse (any ideas how to do that?) with one end connected to a simple timer on the outside tap (to be installed) and the other folded other and sealed with a cable tie then use Gardena Reducing T-Joints (http://www.amazon.co.uk/Gardena-1333-8333-U-Reducing-T-Joint/dp/B0001E41FU) to connect 4mm piping at intervals along the hoses length and hang Coolnet Fogging units like this image below




I feel I could do the whole thing for around £30 if I shop around and it's simple enough for me to do lol

what do you think?

 

@IceColdRum
I assume you are talking about epiphytes, such as Epiphyllum, Rhipsalis etc, rather than your usual desert type cacti. In which case it sounds good the only snag could be water pressure. The micro irrigation systems generally have a pressure reducer between the system and the mains. The Netafilm misters run at 2.5 to 5 bar (35 to 70psi) which you may not get reliably from your domestic supply, especially hot summer afternoons when the lawn sprinklers start. So you could need a booster pump and a header tank.
You will need to get good solid joints as well.

 

Ah. You have spotted a flaw I hadn't noticed I intended on buying a Gardena micro drip kit which includes pretty much everything I need but the filter is also a reducer as you say down to about 1.5 bars I will have to investigate there central sprinkler filter as this doesn't mention reducing the water pressure.

Yes I have around 500 epiphytic cacti, some of which would really like some more humidity and the others will just get on with it

Sent on the go from my telephone

 

I think I will have to buy it and see the gardena kit is cheap enough and if I find there isn't enough pressure from my mains water supply then I will run it from my waterbutt pump instead and then control that by a standard plug in timer

Sent on the go from my telephone

 

The coolnets are pretty good at 60psi. They put out more of a fine mist than a fog so they need to be mounted high up and ideally controlled by a cycle timer which allow for very short misting durations..
It would be hard to attach them directly to standard garden hose due to the odd base fittings (3/8 whitworth thread). You can buy lengths of rigid pipe for them that have predrilled and tapped holes at various spacings.
A mains water pressure testing gauge is a handy tool, screwfix sell a monument for £15 , that screws directly onto a 3/4" bsp outside tap or washing machine outlet.
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