I've been researching this as well. Whatever model I decide upon will get plenty of testing prior to leaving on vacation. Will you be relying on electricity or batteries? Did you know there are also solar models?
Might want to ask this question of professional irrigators too.

Here are just a few I'm investigating so far.

How To Install An Automatic Drip System
http://www.irrigation.learnabout.info/articles/110-install-drip-irrigation.htm

Orbit
http://www.nextag.com/orbit-sprinkler-timer/search-html

Nelson

Carlon
http://www.carlonmeter.com/index.php?q=ftc

Gilmour
http://www.shopping.com/xPR-Gilmour-Electronic-Water-Timer~RD-113316499076

Digital
http://www.gardeners.com/on/demandware.static/Sites-Gardeners-Site/Sites-CATALOG_Gardeners/default/pwr/product-reviews/Gardening/Watering/Accessories/p/33__868-Digital-Water-Timer.htm

Reviews and other brands:
http://www.galttech.com/research/household-DIY-tools/best-irrigation-controllers-sprinkler-timer.php

I started using an orbit model #62015 hose bib timer that I bought from Home Depot last spring. I used it all last May thru Sept full time to drip and micro-spray 30 -40 containers on my deck and never had a problem. It is battery operated which means I can use it out farther on the property where I have no electricity. I was easy to set and can go on multiple times a day if needed. Tomatoes in June for me with my well drained potting mix needed two a days but kept the BER away which I had some problems with the year before from the media drying out too much in a 24 hour period at full fruiting time and with temps above 90. I have it installed on the side of the house under a narrow roof eave. It still gets some sun and rain (weather) but not the full brunt. I would suggest using some protection if your hose bib location is in full sun or exposed to direct weather.

I have been pleased and now need to change the batteries out for the new season (even tho its still working) it takes 3 AA batteries and it is suggested to change out once a year. Makes sense to me and it is worth knowing it went a full season without needing replaced.

One problem I have recommnending this or any other timer is that these days with so much of the work done overseas and the changes that a given vendor will make season to season means that you may not get exactly the same time I have even when the model # is the same. Home Depot is usually pretty good about product that doesn't work so that would be a plus overall. I find it easier to see products like this in person instead of buying over the internet but maybe that is just me. I think doing research is great but more often than not I want to see it in person to make a final choice.

Good Luck and Happy Growing with your homemade media and whatever timer you choose to keep your babies going while you are gone. David

I need to do this for all my potted plants, glad to have found this thread. I also need to put timers on my soaker hoses.

It is a pain to drag the hose all around the yard watering potted plants but I love having them.

We have a Melnor that we got at Home Depot maybe 6 years ago and it still works fine! It can be set on a pre-programmed schedule or you can create your own. Runs on 2 AA batteries that have only been replaced once in the time we've had it. I run the soaker hoses during the summer and it really helped after my heart attack last summer, when I couldn't get outside every day.

Pam

I have for many years used mechanical Melnor timers.(this type is spring loaded, you manually turn on and it turns off after a certain amount of water has passed through) I know that as a brand they have done a good job over the last 20 or so years I have used this type. It is good to hear that their battery timers seem to be up to par as well.
Happy Growing David

whats a vacuum breaker? is it like a pressure regulator? where do you buy them? want to try your idea. thanks for sharing.

Love my Dig timers

We were just talking about these, mostly because one of us is always leavig the hose on for hours.

I think I'll go with the manual ones, no batteries to change and it might survive flooding.
Tally HO!

I bought a Gilmour 8-cycle digital timer from Lowes in June just before I went on a 4-day weekend. It works so well that I bought another one for my front spigot.
It hasn't failed yet (it's battery operated) and I've been keeping close tabs on it while I've been home. Just put fresh batteries in it before you leave and you should be good to go.
No troubles with clogging that you mentioned.

Roman: A vaccum breaker is found in the same area of a store as valves and pressure regulators. There are some that are designed to thread on hose bibs and types for pipe thread so get the type for your application. What it does is not allow water and impurities get past the connection point to insure the water supply is not contaminated. Many states have requirements for these on any irrigation system.
I hope this answers your question and if not ask more and I will try to get back with you on specifics.
Happy Watering David