Hi GTN, Very good question. I'll bet your 3/4" spigot has a 1/2" copper line feeding it nor is a spigot 3/4" through out it's length. Smaller to bigger or vice versa doesn't matter. Size affects velocity at that change point, but very briefly. Length of pipe is what affects the system efficiency (loss of pressure) the most. Water flows faster through the smaller diameter pipe and when water velocity gets high enough turbulence in the pipe is reached and your friction loss per foot of pipe increases as well as noise. This friction loss robs you of pressure as the water travel along the system. Your system has high pressure so this not a big concern in your system. It becomes a design issue depending on where you reduce your pressure for your garden. 1 1/4" pipe was sized by a formula that calculates flow versus velocities in various size pipe. A standard design criteria for non-turbulent flow is less than 5 feet per second velocity(noise reduction). Using that criteria the 1 1/4" was acceptable, 3/4" would be less acceptable but still can be utilized with no real problems. It then becomes a cost issue. It makes no difference what size the source pipe is, but hooking up to your house affects the velocity of water traveling through your house pipes. If you turn on your hose, how noisy is the flow in your house? Does it affect the flow of other water using appliances being used at the same time? Turn on the washer, shower, kitchen faucet, etc an listen to the sounds of the water. If the answer is no to these questions your house water system doesn't pose a constriction to your garden water needs. The more items being run the noisier it gets. Did you ever call your builder and find out about the pressure regulator needed for your house water system? Just curious. GL. Aloha

dm, Do some experiments with your system. The important thing is water getting to the roots at various stages of growth and weather. Usually the movement of soil is based on soil type. You can change the basic structure of your soil but not by much. So run the system for varying lengths of time and see how far and deep the soil moves in the soil for varying times after you finish irrigating. You are mapping your soil profile with the depth of your plants as they age (root growth). Do this for Spring Summer and Fall for different season maps. When you have done this you can give expert opinions on GardenWeb. Or go by the "rule of thumb" of about an inch of water a week Spring and Fall and an inch and a half for summer. Or "Rule of thumb" part 2 with about 1/2 to 1 gallon of water per plants every three days. With the rule of thumbs you still have to check if this is too much or too little over time (depends on soil). Gardeners check their plants somewhat frequently that the plants are getting what it needs. JMHO Aloha

Hi GTN, How much money would you like to spend. Drip tape is the way to go. Soaker hoses clog and are more expensive over time because of replacement. Place PVC mainline with drip tape through the actual garden beds. Drip gives more even and controlled flow, handles pressure better and has cheaper fittings than emitter systems. The cheapest method is just 1/2" pvc sch 40 pipe through the beds with small hole drilled in it. Drill holes small, then larger and larger as you check the flow at various spots in the lateral until you are satisfied the plants are getting the amount and rate you want. Life is trial an error. GL Aloha

Your garden is beautiful so great, I loved your explanations very easy to understand. Best of luck with your wonderful garden. I have been thinking about doing this myself I did stock up in the weed block cloth at the end of the season last year. Please keep us posted on how well it works for you. We have had a record breaking winter this year I am so ready for Springtime, and Summer.