You might try a hand held. Use it regularly and you should get a better feel for what is needed as the season change.

I don't know of a system that comes that way from the factory but I'd think that you could wire it to operate that way so that any sensor would override the whole system... if that's what you're looking to do. If you had a valve-in-head system, you could have each head come on as needed based on sensor readings. That's one that I've been playing with in my head. Yes, it would be more expensive but it should be more effective and efficient.

I work for Acclima and stumbled accross your message while I was looking for something else. We actually do sell several systems that give you the ability to connect multiple sensors. One that is just being released is a 36-zone, stand alone controller. It allows you to connect a sensor on every zone if desired. In practice you will place a sensor in each microclimate, then from the controller specify for each zone which sensor you would like it to track. A 24-zone model of this controller will be available shortly.

The RS500 can be used to control multiple microclimates, even with one sensor. Typically the sensor is used only for the turf irrigation. Place the sensor in the area that dries out the quickest, then adjust watering times on other zones to compensate. Drip zones are left on timed mode.

Our sensor is the only absolute, stable sensor on the market. It has been tested by CIT, Utah State, and numerous other institutions. Please email me if you would like more information. slundstrom@acclima.com

(shakes head.... Must... Not... Buy... Acclima... 36... Zone... System... )

I'm not being sarcastic at you samlundstrom but I AM being sarcastic at me. You see I'm a gadget freak and just love things that take the chore out of everyday tasks. I'm disabled and only recently got into this gardening obsession and have bought a couple of Hozelock timers for my garden and though I looked for a single system that could control mulitple areas (front garden, back garden and mini greenhouses) I couldn't seem to find squat here in the UK.

It's sods law that I've laid out the front and back garden irrigation out and now I find two systems that use sensors to stop wasting water. The other one I found was a UK company (see link below) and I still may get a better system after I've seen how I cope this year.

It's ironic though, I just setup the back garden watering system and watched it turn on (hooray I shout)... then just seconds after the soddin' heavens opened up and totally soaked me and the garden and there was my automatic watering system still pushing out the litres to add to the newly created swamp. Go figure...

Seriously though, anything that will reduce the amount of water usage is good for the environment. At the moment I'm just glad I'm not on a water meter as my Bamboo is one thirsty plant hehe.

Oh yeah I nearly forgot... another reason for me being sarcastic at myself was the fact that I only have a small garden and making it use more than 4 zones would mean I would have to start making every container become a seperate zone which is kind of on the obsessive side heh. Still if I DID have a big garden it would be excellent to have such flexability.

Here is a link that might be useful: UK Watering System (Gardena)

That looks like a good unit to consider, samlundstrom. I was unable to read much information but let me know if I understood correctly: basically, one connects the RS500 to an existing controller; one sets the existing controller to water daily; at watering time, the RS500 then turns off the zones that are "too wet".

Things I was not sure... (1) my existing controller uses 12 zones; can RS500 handle that? (2) can RS500 also turn off zones based on the current outside temperature (say if the temp is close to or below freezing)? (3) I am almost sure the answer here is no but can RS500 also turn off zones if it is too windy (water will end up where it is not wanted, like the street)?

Thanks, Luis