What it is
Quarter-inch tubing comes two ways: blank micro tubing, which carries water to a separate emitter, and dripline, which has emitters built in at a fixed spacing. Raised bed kits such as Rain Bird’s lay dripline in rows. DIG’s Microline, for example, comes with emitters every 6, 9 or 12 inches on tubing .170 inch inside by .250 inch outside.
How long one run can be
Each maker limits the length of a single run so the far end still gets water. DIG gives 16, 22 and 28 feet for its Microline at 6, 9 and 12 inch spacing at 25 psi. Raindrip gives 50 feet as the maximum run for its ¼-inch tubing. Rain Bird says ¼-inch blank tubing running from the main line to an emitter should be no longer than 5 feet. Check your own dripline maker’s figure; the drip parts calculator flags rows longer than DIG’s limits.
Emitter spacing and flow
| Dripline | Emitter spacing | Flow per emitter | Maker |
|---|---|---|---|
| DIG 1/4 in. Microline | 6, 9 or 12 in | See maker | DIG Corp |
| Rain Bird ET256 emitter tubing | 6 in | 0.8 gph | Rain Bird |
| Raindrip Drip-A-Long (non-compensating) | 12 in | ½ gph | Raindrip |
| DripWorks Soaker Dripline | 12 in | About 0.80 gph | DripWorks |
Pressure-compensating emitters keep a steady flow across their pressure range, Netafim explains; non-compensating ones do not. Raindrip notes that with its non-compensating dripline, flow varies with the length of tubing and with elevation, higher near the source.
In the kits we cover
The Rain Bird GARDENKIT includes 35 feet of ¼-inch emitter tubing with 70 pressure-compensating emitters every 6 inches. The Epic kits use drip tape instead, eight tapes of up to 10 feet each. Plan rows and lengths with the drip parts calculator.