pressure drop
Hi Jeff:
As I mentioned before, I don't use sprayheads, although I have in the past. Most sprays require different run times than emitters, so hence seperate zones are used for each. I think Xeripops like at least 20 PSI to function properly. Depending how long your 1/2 inch line runs, and the distance from the water source to the last XCeripop, and how much the total volume draw on that zone measures, will depend on the pressure and volume left by the end of the line. So, your last Xeripop may not perform as well as a more proximal one. I don't know what spray heads you are useing, Some use larger flow rates, compounding the problem.
Another solution for beds is drip along line. The emitters are built into the line, which is available in 1/2 and 1/4 inch diameters. The 1/4 inch is easilhy snaked between individual annuals. Most find this too much trouble, and in that case, sprays are the only option.
Consider running a seperate 1/2 inch supply to the sprayers for best results. BTW, all 1/2 inch is not 1/2 inch. Many are really closer to 5/8 inch internal diameter, and carry about twice as much water. Thant could be important for sprays.
Please note again. I have never used Xeripops, but have used sprayheads. And am assuming your spray heads prooduce similar parcipitation rates, making the above apply.
Hope it helps, Jeff