I'm dubious about a 120-foot line of drip tape being able to emit well along the whole length of the tape unless you are using the expensive agricultural tape. You will be losing PSI all along the tape, and may not have enough force to reach the ends.

http://www.dripirrigation.com/drip_irrigation_chapters/9/drip_irrigation_pages/39

http://www.dripworks.com/category/ttape1

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You need to calculate how far below the input of the siphon your plots are, and from that calculate the PSI to them.

1 pound per square inch = 27.6704523 inches of water

So your pond has to be about 25 feet above the level of the gardens. Or you need a small elevated water tower to give you the pressure for the drip.

Suppose I divided the plot into 2 zones, 60 ft drip tape each? Today I was able to syphon 140 gal/hr over 100 foot of garden hose. If I use 1'' irrigation tubing that should increase gph. Will the gph drop over the run from garden to pond?

Forgive my fallacy in math but how do you figure my garden needs to be 25 below pond level?

You have two separate problems and together they'll kick your butt. You are underestimating back-pressure. Pressure drop in a 3/4 inch garden hose is 82 psi over 550 feet at 10 gallons per minute, or 40 psi at 5 gallons per minute. That 5-10 gallons per minute won't ever happen.

I think a 550 foot siphon will have such low pressure at the end, especially through a 3/4 inch line and a crud filter, that you will need lazygardens' suggested intermediate water holding "tower" (a 55 gallon drum?). That way you get a very modest pressure head and you will no longer have to care about siphoning rates since you will have 24 hours in every day to actively siphon.

However, even if you do increase the water supply you're trying to shove all that low pressure water through 2400 feet of drip line! At ten pounds, no way. Perhaps a siphon-fed booster pump (that would run for a measly ten minutes a day) might be useful to fill that tower you had to hoist way up for head.

At some point in the plan you will have to work energy into the system.

So take a 300 gal tank, have it placed above the field but below pond level, and I have a 'water tower'? Coldweatherisevil seems to think the siphon will flow over the 550 feet, so I should be able to use the siphon to fill the tank...

It'll be sitting a slope, but that shouldn't be an issue, right? As long as the line feeds downhill....

Will this be able to feed that 2400 ft of drip tape properly? I'm considering dividing the system up into 2 or more zones for added pressure....

I think your supply line needs to be much bigger than 3/4 if gravity has any chance of working. Something like 1 1/2. You could maybe get away with dropping down sizes after an amount of drop in height. I would think the first bit of the line should be a bigger size and progressively get smaller. Like run you could run the first 150' in 2", next 150' could be 1 1/2".... Etc.

That way you wouldn't be having any friction loss and you would have a larger volume of water pushing on then drip line