The Watering Year: How a Claremont Landscape's Schedule Changes

Almost every irrigation problem in this town starts with the same mistake: a controller set once and then left alone. A schedule that is right in the heat is wasteful in the cool months and actively harmful in the wet ones, and a schedule that is right in winter will not carry a landscape through an August afternoon.

Watering here is a CURVE, not a setting. This is the shape of that curve across the year, and what a household should be doing at each point on it.

One thing this article deliberately does not do is tell you how many days a week to run a station. Watering rules, allowed days, and any restrictions in force come from the water provider serving the property and from the City of Claremont, and they change. Get them from the source, then apply the seasonal logic below inside whatever the current rules allow.

The wet months: the season of doing less

When the rain actually arrives, the correct irrigation setting is usually far closer to off than most controllers are set to.

Plants are not transpiring much, the soil is holding water, and the ground is doing the job. Running a full schedule into wet soil does three unhelpful things at once: it wastes water, it pushes moisture against foundations and hardscape where you least want it, and it encourages shallow rooting in exactly the plants that will need deep roots later in the year.

This is also the season when the drainage side of the property gets graded, and irrigation is part of that picture. If your system is adding water to a yard already struggling to shed it, you compound the problem described in the atmospheric river guide.

The job that matters most in these months is watching. A wet season shows you where water pools, where it runs, and which parts of the yard drain and which do not.

Spring: the ramp, and the audit

Spring is the busiest season for a controller and the one most owners skip.

Two things happen at once. The ground begins drying from the top down, and growth accelerates - so demand climbs steeply over a few weeks. A schedule left at its winter setting falls behind; a schedule left at its summer setting overshoots.

Spring is also the right time for the annual system audit, because you want faults found before the heat rather than during it. Run each zone while you watch it. You are looking for the classics: heads spraying hardscape, a station that no longer covers what it used to, a drip line cut by a shovel, a valve that seeps, and pressure that has quietly changed since last year.

The planting side of the same season is covered in the planting calendar, and the two decisions are related - anything newly planted has its own establishment schedule, which is not the schedule the rest of the landscape is on.

Summer: peak demand and deep watering

The warm months are where the annual water bill is decided and where a landscape proves or disproves the way it was designed.

The first principle is deep and less frequent rather than shallow and daily. Shallow daily watering keeps roots near the surface, which is precisely where soil dries fastest, so the plant becomes more dependent on you rather than less. Deeper, less frequent cycles push roots down toward moisture that lasts.

The second principle is timing. Water applied in the heat of the afternoon loses a large share to evaporation before it does anything useful. Early is better, and it also gives foliage time to dry.

The third is that not everything on a property wants the same thing. Turf, established trees, shrubs, and pots have genuinely different needs, and one schedule applied to all of them will over-water something and starve something else. Established trees in particular are usually the most valuable living things on a Claremont lot and are often the least deliberately watered.

What all of this looks like when a house is on the market is covered in the summer curb appeal guide.

Autumn: the taper nobody does

The most commonly missed adjustment of the whole year is the autumn step-down.

Heat lingers, so reducing feels wrong. Then the days shorten, the nights cool, growth slows, and demand falls well before the weather appears to have changed. Controllers left at their summer setting through that stretch waste a great deal of water at exactly the point when nobody is watching the bill.

The signal to follow is day length and night temperature rather than the afternoon high.

Two things worth automating

If you do nothing else, two changes remove most of the annual error.

A rain sensor, or a controller that responds to weather. The most visible irrigation failure in any neighborhood is a system running in the rain, and it is entirely avoidable.

A seasonal adjustment feature. Most modern controllers can scale every station by a percentage. Changing one number as the season moves is realistic; rewriting the whole program four times a year is not, which is why nobody does it.

The pattern to remember

Demand climbs steeply through spring, holds high through the heat, tapers earlier in autumn than instinct suggests, and drops close to nothing in the wet months. Landscapes chosen for this climate ride the curve without drama. Landscapes chosen for a wetter place fight it every year, and the water bill is where that fight shows up.

Anthony Grynchal has been licensed in California since November 2009.

Work through the rest of the local year at the seasonal guides hub, and see the season that sets the whole curve in the summer guide.