The rain that falls on your roof is the cheapest water you will ever have, and most of it runs away. This page answers one question: how do you put that water at the roots without a pump, a filter stack, or an electric bill? The temple's practice is a 55-gallon barrel, about fifty dollars in parts, and gravity doing the work — one afternoon to build, nothing to burn out.
The problem, plainly
A garden needs water steadily, but rain arrives in bursts. On sandy ground the problem is doubled: the soil cannot hold a flood — it drinks, but it drinks slowly — so a heavy rain either runs off or sits, and the dry week after leaves the beds begging. The usual fix is machinery: a pump, a pressure tank, a timer. All of it costs money and all of it can fail. The site's own arithmetic is the whole argument: about fifty dollars for the barrel, blocks, spigot, screen, and a length of downspout, and one afternoon to put it together. There is nothing to burn out.
What actually works
Gravity is the pump. Raise the barrel on blocks, fit the spigot low, and the lower it sits the more of the barrel empties; a short hose turns it into a filling station at the bed. The barrel fills itself — screen the top and aim the downspout in. Three details separate a barrel that works from a barrel that breeds mosquitoes: a first-flush T-fitting that sends the first minutes of rain — the dust and bird droppings — to the ground, so the clean water stays clean; a fine-mesh screen, one millimeter or finer and sealed around the opening, so the water stays dark, covered, and still; and an overflow pipe that carries the surplus away from the foundation when a downpour fills the barrel. The practice pairs the barrel with a buried olla in the bed that dries fastest: the barrel fills the pot, the pot meters the soil. Gravity meets capillary action — that is the whole system.
How to run it
- Read the roof first. Choose the run with the most roof above it, closest to where the water is needed. The shed often has the right one already.
- Let the first flush run — a five-dollar T-fitting sends the first minutes of rain to the ground.
- Raise the barrel on stable, level blocks high enough for a watering can under the spigot. A full 55-gallon barrel weighs about 450 pounds, so the blocks want to be solid.
- Fit the spigot low, then seal a fine-mesh screen — one millimeter or finer — around the opening.
- Aim the downspout in and fit an overflow, so a full barrel sheds surplus away from the foundation.
- Pair it with one olla at the root zone and refill the pot every three to seven days in summer. Before the first hard freeze, drain the barrel, turn it over, and let the roof shed to the ground until spring. That is the whole maintenance list.
Where it fails
- An open or loose screen. An unscreened barrel is a mosquito nursery; the screen must be sealed around the opening.
- No first flush. The first rain after a dry spell washes the roof into the barrel, and the water goes bad.
- The spigot set high. Gravity can only empty what sits above the tap; a high spigot strands half the barrel.
- No overflow. When the barrel is full, the water wins — surplus finds the foundation unless the overflow gives it a path.
- Skipping the winter drain. A full barrel freezes and cracks, and spring starts over. Drain it before the hard freeze.
- Adding a pump anyway. A pump in the loop adds cost and failure for no gain — gravity already delivers.
The short version
Put the barrel under the roof run with the most water, closest to the beds. Send the first flush to the ground, seal a fine screen around the opening, raise the barrel high enough for a watering can, keep the spigot low, and give a full barrel an overflow path. Pair it with one buried olla in the driest bed, refill the pot every three to seven days in summer, and drain the barrel before the first hard freeze. About fifty dollars, one afternoon, and gravity runs it from there.
From the Water-Wise Gardening FAQ
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