Start at the spigot with a backflow preventer, a timer, a filter, and a pressure regulator, in that order. Then run 1/2-in supply tubing to a header across the end of the beds, with drip tape or emitter tubing down each bed, a connector and an end closure for every line, and staples or stakes to hold them. For three 4 × 8 ft beds you'd buy about 106 ft of drip tape and 46 ft of supply tubing, 10% extra included.
Open this example in the Drip Irrigation Planner
The parts, in the order the water reaches them
A drip system has two halves. At the spigot, a short chain of parts protects your house water and cleans and slows the water down. From there, tubing carries it to the beds and along every row. Extension guides list the parts at the spigot in this order (Drip Irrigation for Home Gardens):
- Backflow preventer. A one-way device that keeps garden water from being sucked back into your home's drinking water. It goes on the spigot first. Ask your building department or water provider what's required where you live.
- Timer or control valve. Turns the water on and off. A battery hose timer is optional, but it means you never forget to water or to shut it off.
- Filter. Catches grit before it clogs the tiny holes the water drips from. Use a 150–200 mesh filter on city water; "mesh" is the number of openings per inch, so a higher number is finer. If your tubing's label gives a minimum mesh, use at least that (Part I: Drip Tape Irrigation for Cut Flowers).
- Pressure regulator. Lowers household water pressure to what the tubing is built for, in psi (pounds per square inch): about 8–15 psi for drip tape (Part I: Drip Tape Irrigation for Cut Flowers), or about 20–30 psi for emitter tubing (Drip Irrigation for Home Gardens). Use the pressure printed on your tubing if it differs. Don't skip it: tape fed straight from the spigot can burst.
After the regulator comes the tubing:
- Supply line: plain 1/2-in poly tubing from the spigot to the beds.
- Header: the same tubing laid across the end of the beds. Every drip line starts from it.
- Drip lines: drip tape or emitter tubing running the length of each bed.
- Fittings: a connector where each drip line joins the header (you punch a hole in the header for it), a closure at the far end of each line, an elbow where the supply line turns, and an end cap on the header.
- Hold-downs: staples or stakes so the lines stay put. Use 6–8 in staples for tape and leave them a little proud of the soil so the tape can swell (Part I: Drip Tape Irrigation for Cut Flowers).
Example: three 4 × 8 ft raised beds
Three 4 × 8 ft beds, planted closely (greens, carrots, onions), with 2 ft paths and the spigot 25 ft from the first bed. Drip tape, a 1/2-in supply line, and the planner's default estimate of 5 gallons a minute from the spigot. The planner gives:
The full parts list
| Qty | Part | Notes |
|---|---|---|
| 1 | Backflow preventer, hose thread | First part on the spigot. Check local code. |
| 1 | Timer or control valve | Optional, but saves you remembering. |
| 1 | Filter, 150-200 mesh | Before the regulator. |
| 1 | Low-pressure regulator, about 8-15 psi | Low-pressure regulator matched to your tape's rated psi, typically about 8-15 psi. Extension guides reduce tape to 10-15 psi; above 15 psi tape can burst. |
| 1 | Supply line adapter, hose thread to 1/2 in | |
| 46 ft | Supply line and header tubing, 1/2 in | Includes 10% extra. |
| 1 | Elbow, 1/2 in | Where each supply line turns along its beds. |
| 1 | End cap, 1/2 in | One at the end of each zone's header. |
| 106 ft | Drip tape | Includes 10% extra. |
| 12 | Drip tape start connectors, barbed | One per line. A few spares help. |
| 12 | Drip tape end closures | One per line. |
| 24 | Drip tape hold-down staples, 6-8 in | Staples about every 20 ft, plus one at each end of every line. |
| 1 | Hole punch for the header |
The tubing lengths include 10% extra for cuts and mistakes; the fitting counts are exact, though a few spare connectors help. The 106 ft of tape is 12 lines × 8 ft = 96 ft, plus the extra.
What changes with emitter tubing
Switch the same three beds to 1/2-in emitter tubing and most of the list stays the same. Four things change:
- Regulator: about 20-30 psi instead of about 8-15 psi.
- Filter: 200 mesh.
- Hold-downs: 60 stakes, one about every 2 ft (extension guidance), instead of 24 tape staples, one about every 20 ft plus one at each end (Part I: Drip Tape Irrigation for Cut Flowers).
- Flow: 86.4 gallons an hour (gph) instead of 19.6, so the weekly watering drops from 3 h 3 min to 42 min. Both still fit in one zone.
Run your own numbers
The free BedMath Drip Irrigation Planner works this out for your beds, spigot, crops, and tubing, and shows every formula and source. This link opens it with the example above filled in.
Sources
Published 2026-11-03. The numbers in the examples come straight from the planner.