How Much Soaker Hose Does a Bed Need?
A soaker hose waters by weeping along its whole length, so it needs to actually sit beside every row of plants to do its job. The amount you buy is set by two things: how long the bed is and how far apart you space the parallel runs. Tighter spacing wets the soil more evenly but eats more hose. For a 20 ft by 4 ft raised bed at standard 18 in spacing you get about 3 parallel runs, which is roughly 60 ft of hose lying in the soil, plus a little extra to U-turn between runs.
Runs = floor(Bed Width / Run Spacing) + 1
Hose Length = Runs x Bed Length + turn allowance
Spacing depends on your soil. Sandy soil drains sideways poorly, so water spreads only 6 to 8 in from the hose and you want runs about 12 in apart. Heavy clay wicks water 12 in or more to each side, so 24 in spacing is plenty. Most loamy garden soil sits comfortably at 16 to 18 in.
How Long to Run It
Deep, infrequent watering beats a daily sprinkle because it pushes roots down where the soil stays moist. The standard target is about 1 inch of water per session. One inch over one square foot is 0.623 gallons, so a 20 x 4 ft bed needs roughly 50 gallons for a full inch.
Pressure Sets the Clock
Soaker hoses are slow on purpose. At normal household pressure a hose weeps somewhere between 0.5 and 1.1 gallons per minute for every 100 ft of length. Run 60 ft at the typical 0.75 GPM/100 ft rate and you are delivering about 0.45 GPM, so that 50-gallon, one-inch soak takes a little under two hours. A hose-end timer turns this into set-and-forget watering.
Frequently Asked Questions
How far apart should soaker hose runs be?
Match the spacing to your soil. In sandy soil water barely spreads sideways, so keep runs about 12 in apart; in loam 16 to 18 in is standard; and in heavy clay water wicks well to the sides, so 24 in lines still keep the whole bed moist. When in doubt, dig down a few inches an hour after watering to confirm the wetted zones from neighboring runs are overlapping.
How long should I run a soaker hose?
Aim for about 1 inch of water per session, which for a typical raised bed lands in the 60 to 120 minute range at normal pressure. The exact time depends on hose length and water pressure, since a soaker only weeps about half to one gallon per minute per 100 feet. Check the soil 6 inches down afterward; if it is still dry, run it longer next time.
Why does the far end of my soaker hose stay dry?
Long single runs lose pressure as water seeps out along the way, so the last several feet barely weep. Keep individual runs under about 100 feet, lay the hose as level as possible, and if a bed needs more than that, split it into two shorter loops fed from a Y-splitter so both get full pressure.
Should I bury a soaker hose or leave it on top?
Lay it on the soil surface and cover it with 1 to 3 inches of mulch rather than burying it deep. Mulch cuts evaporation and protects the hose from sun, which is the main thing that cracks soaker hoses, while keeping it accessible to check for clogs. Buried hoses are hard to inspect and clog more often from soil and roots.
Practical Guide for Soaker Hose Length Calculator
Buy a little more hose than the bare run length suggests. Soaker hose is sold in fixed lengths, usually 25, 50, 75, or 100 ft, and you need a few extra feet for the U-turns between rows plus a solid (non-weeping) feeder length to reach the spigot. This calculator rounds your purchase up to the next 25 ft increment so you are not left a few feet short with the bed half plumbed.
Keep each continuous run under roughly 100 ft. Soaker hoses bleed off pressure as they go, so a very long single loop weeps generously near the tap and goes nearly dry at the far end. For a large or long bed, run two shorter loops off a Y-splitter instead of one marathon line, and put each loop on the same timer so the whole bed gets a uniform soak.
Pair the hose with a simple mechanical or battery timer and a pressure reducer. Most soaker hoses are happiest at 10 to 25 psi, well below typical household line pressure, and over-pressurizing them makes them spray, split, or blow off fittings. A cheap pressure reducer plus a timer turns this into true set-it-and-forget-it deep watering that runs at dawn while you sleep.
Quick Checklist
- Set run spacing by soil type: about 12 in for sand, 16 to 18 in for loam, 24 in for clay.
- Keep each continuous soaker run under 100 ft, splitting long beds onto a Y-splitter.
- Add a pressure reducer (10 to 25 psi) so the hose weeps instead of sprays or splits.
- Cover the hose with 1 to 3 in of mulch and run it on a timer at dawn for a deep soak.