Todd, Man you are doing the hard stuff. Two ibuprofen is better. Here is the hydraulics. Approximately 0.5 psi for every foot of elevation the water level is from the garden surface. For example if the height difference is 10 feet you will experience 5 psi at the garden outlet pipe. The pressure will decrease as the height of the water level decreases. In low pressure water distribution pipe sizes need to be bigger because your flow velocity will be low. See what flow your system will deliver by filling a 5 gallon bucket up and timing the fill. Do it several times and average the gallons per minute. You will now know how long it will take to deliver a certain amount of water to a zone. At least you won't need pressure regulators but probably a filter screen if your going with drip or soaker hoses. Think about pvc with holes drilled into it at what ever spacing you need(I can help you with this). You need to calculate the usage flow rate of the drip tubing or soaker hose to plan correctly for even distribution. Who will coordinate the water regime for the garden? Talk to a local landscaper to help you and you will advertise his name in the garden. Trial and error is a way of learning life. Aloha

It's bulk soaker hose. I've have poor luck with hoses near 100'. Works better on shorter runs. Make sure you use a pressure regulator. I'm not crazy with the snap on coupling. I use hose repair couplings. I've found the hose made to a specific length (25', 50', etc)are easier to use and come with all fittings installed.

When I started my garden, I used soaker hoses. The roses were babies and the circles of hose around them were small. Then the roses started growing and compost and mulch had been put down several times on top of the hoses. Pulling the hoses up in order to enlarge the circle around each rose was a pain in the butt and tricky, often tearing the roots. The most serious issue with soakers is the type of soil you have. In clay soil the water from the soaker will spread wider before it flows downward. In sandy soil it doesn't spread as far before gravity pulls it down, so more circles of hose are needed to wet the same area and more water is required. I found them to be inadequate during the Florida summer with my sandy soil. In the winter of 2010 I switched to micro-sprinklers from Lowe's like Nanadoll described. I like the sprinkler heads, which are basically misters, because I have placed them so that the whole bed is watered, i.e., the whole root zone of the roses and companion plants which keeps the soil cooler and the microbes happier with no dry areas. It's a very flexible system in that connections are easily plugged if not needed, moved or added on. The different radiuses mean there is very little overspray and wasted water. My only problem with the micro system has been the squirrels. They chew into the connectors (and regulators, valves, hose-end converters, etc), creating geysers, loss of pressure and dry garden beds, so if you run the system while your still asleep (like I do) unless you test the system regularly, you won't know you have a problem until the plants start to decline. I have had to bury the connectors or wrap them in hardware cloth to protect them from the %^#%@$* squirrels. I also wrapped the 1/4" lines going to the pots because the squirrels would cut them. They chew off the top on the shrubblers (they spray in a wagon-wheel pattern) which creates a geyser. Also, some of the little connectors between 1/4" tubing & the 1/2" poly are tricky because there is a right way and a wrong way to insert them in the poly. If you insert the wrong end into the poly, it's not a secure connection and it will pop off - uh-huh, creating a geyser. So there is a learning curve to this system, but once you get the hang of it, it's great. I'm very happy with my micro system. I only have a .17 acre lot (60x125) that is all garden, and I used at least 400' of 1/2" poly. The great thing is that you can easily extend it which I have done. Pressure has not been a problem, and I have sprinklers about every 6' on both sides of the beds. But I have learned to despise squirrels with a deadly (I wish) hatred since they also chew the canes on my climbers constantly. Sherry Here is a link that might be useful: If only sweat were irrigation...

But gravity doesn't care where the water goes when it leaves the hose, I do. I have read that each 3' of elevation of the reserve yields 1 psi for distribution. For me, this eliminates any hope for soaker hose or drip tape to regulate the water spread in the garden. It looks as if that goes for original scenario. My latest design now is to set up 5g buckets that will be filled from the rain barrels. It is a larger storage filling at the rate of the rain fall and feeding to smaller reserves to store water for even lower volume distribution. Each 5g bucket will have smaller hoses (1/4" or smaller) with a hole to let water seep out directly to each plant. I am not sure how this will work for the 1.5 acre (65Ksq ft) garden but I will be experimenting with this in my 300 sq ft of raised beds and flower gardens.