As I understand it, both for turf grass and trees, the objective of less-frequent, deep, slow watering is to allow the water, at a drip rate (no run-off), to seep down very deeply, encouraging the roots also to dive/grow deep.

The frequent, perhaps high-volume watering doesn't penetrate deep enough, perhaps with some run off, so the roots aren't encouraged to grow deep.

Deep roots can find water when the soil near surface is hot and dry. This is the role of deep-diving tap roots in woody plants, and in desert palms than can tolerate draught.

btw, one hour doesn't seem very long for a soaker hose. Have you measured how many gallons that is? I've seen soaking to mean overnight, many hours, every 2 weeks.

The deep-soaking approach only works if the soil is such that the water actually goes down deep. Somtimes there is a impenetrable hard pan that causes the water to go horizontally rahter than vertically.

would it not be more effective, and eco freindly to fill a bucket and soak the palm in that for some time? Just up to the soil level, and keep topping it up throughout the day?
Over here, running a hose all night is a no no at the moment, the words hosepipe and ban come out to play every summer!

oh, your palm is in a container? Then the "deep" watering makes no sense. Your frequent watering does, since containers usually dry out quicker than the ground.

When you water a well-draining container, you should see some water come out the drain holes after a few seconds.

Hi:
Thanks all for your comments.

I must not have been clear. The palms are not in a bucket but in the ground and are 15 - 20 feet tall.

unautre: Do you have a recommendation on how much water, gallons, is required for palms of my size?

If you look around San Diego, with its 10 inches of rain per year, you see plenty of huge, mature, healthy CIDPs, even growing on the embankments of the freeways or other places where they receive no moisture but your sparse rain.

I read something about "head in the fire, feet in the water" but I think that was date palms (full intense desert sun above with plenty of moisture at the base). CIDP's can tolerate drought, but grow faster with plenty of moisture.

I have no idea about gallons per hour or per tree size. Some numbers for trees:

http://www.paramountlandscape.com/irrigation.htm

http://www.thestate.com/mld/thestate/living/12753624.htm

fwiw, I've read where the very thirsty and invasive salt ceder can consume 400 gallons/day per treee!! Serious infestations cause the water table to drop, and the remaining water to be salty, brackish, killing native plants.

btw, I've seen metered watering controllers in the chain stores where you can select the qty of gallons, after which the meter shuts off the water. They are not cheap, but neither is water. Then you know that you've just watered with, eg, 200 gallons and can compute the cost from your water bill. :)