How to gravity irrigate from a pond on a timer?

In theory I completely understand that a pond up high on your property can be used to irrigate things farther down the slope.  In practice I have a large veggie garden that I occasionally need to water (automatically when I'm not home).  It's relatively flat but probably loses a foot of elevation across the garden.  It's 120' by 60'.

From the garden the ground slopes upward to the high point of the property which is only 5' higher.  If I dig out a pond and push up a dam I could probably get water to be 4' higher than the garden.  I think that would give me under 2psi of water pressure at the garden.

Is there any drip irrigation that can operate under 2psi?  I have 27 raised beds that are all 25' long so distribution among the beds is a challenge.

I could always pump the water out of the pond at higher pressure.  But then I might as well put the pond lower on the landscape to catch more runoff.

I do have sandy soil so even getting a pond to hold water may not be worth the trouble.  I have a shallowish water table so I could do a windmill to bring up water.  I'd still have the low pressure issue though.

Any thoughts out there?  Does anyone distribute irrigation water to planting beds with low pressure and in an automated manner?

Options I've thought about:
Run a hose and hand water the garden - works fine except if I'm not there during a dry spell
Have a windmill fill the pond (to overcome leakage and water usage during dry spells) and pump water from pond through sprinklers on a timer
Improve soil so that watering isn't needed - in the works
Mulch - already doing but the soil is quite sandy in my area

Mike,

From what I am reading, and pardon me if I wrongly assume, you are thinking of irrigation systems in a commercially available sense?  At the risk of sounding flippant, a hose with holes poked in it is an irrigation system that works under 2psi.  I think with the low pressure, you need to step back and think in terms of low tech solutions.  Drip tape or other simple irrigation would work if you incorporated a solar powered solenoid or timer on the outflow of the pond.  Set the timer and walk away.  2psi of water would be slow drip but water will always seek its own level.  LLDPE tube can be had for about 6 cents a foot.  You would have to establish your drip rate at the far end of the hose and reduce progressively the number of holes as you traveled back up the system to keep from drowning the near end and dehydrating the far end; but with a little empirical trails, one could get a very cheap irrigation system set up that is pure gravity flow.  A very small solar panel system would provide more than enough current to open and closes a small valve.  Also a little 30 gallon per minute solar 'pond pump' might be an option.  

some examples:  http://pickmypondpump.com/best-solar-pond-and-fountain-pumps/

http://www.usplastic.com/catalog/item.aspx?itemid=23758

http://www.ebay.com/bhp/solenoid-valve-12v

I have more info on this topic in my book.  Drip tape or turbulent flow emitters operate on low pressure but 2psi may not be enough pressure to equally distribute water via drip tape but it still works.  Manufacturer recommends 4psi for drip tape.  They also make rain barrel soaker hoses that operate off .4psi but with soaker hoses or holes in pipe you won't get even distribution.  For automation you'll need a mechanical valve.  Toro makes a hose bib valve and some of the older gilmor's work.  Best would be a zone valve for hydronic heating (Taco zone sentry) that could be connected to irrigation control timer.

Thanks Jack and Shawn for your replies!

Jack:  Yes, I'd like to use commercially available hardware if I can.  But I'm fairly handy and can piece together things as needed.  In a previous garden I had an IBC cage tank on an 8' tower as a personal water tower.  I used a solar powered timer valve (since most faucet timers rely on city water pressure to operate).  I fed the water through 8 raised beds with 1/2" pvc pipe with little holes drilled in it.  The issue I had was I'd get much more water on the low ends of the pipes.  Based on that experience I don't see how I could water 20 more beds in a garden with even more slope and less head pressure using a pipe or hose with holes in it.  Unless the flow is diverted from one section to another during the water cycle (row 1-4 for 30 min, then row 5-8, etc).  Then I'd be into multiple timers but maybe that's the only way to make it work.

Thanks for the solar pond pump link, I hadn't thought of a lower pressure pump.  Maybe that could overcome the variation in the pipes from the low end to the high end

Shawn:  Thanks for the minimum flow info.  Maybe I could combine a small solar pump with the 4psi drip tape...  I've added your book to my Amazon wish list

I'm still hoping someone will chime in who has actually faced this same situation and has a working system. (fingers crossed)