How to Set a Landscape Lighting Timer, and When to Change It

Illustrative times. Confirm the actual timer mode, local clock and whether the device adjusts automatically.

When local clocks move back for daylight saving time, a landscape-lighting schedule may need a check. A photocell follows ambient light; a clock timer follows clock time; a countdown timer runs for a selected duration. This guide explains the difference so you can adjust the mode your actual model uses.

• Clock time check it when your local clocks change
• Photocell responds to ambient light, not the clock
• 6-hour example starting at 5 p.m. ends at 11 p.m.

What the clock change does

Nothing happens to the dark. It arrives when it did the day before; the clock just reads an hour earlier.

Illustrative example: if the photocell turns on at 5 p.m. and the countdown is six hours, the lights turn off around 11 p.m. Actual turn-on depends on local light and sensor placement; use the observed time at your home rather than an unsourced city sunset table.

The photocell responds to ambient light. After a clock change its switch-on time may appear about an hour earlier on the clock, even though it is responding to the same evening light. The switch-off behavior depends on the selected control mode.

Which kind of timer you have

Look at the settings on the transformer, or on the timer if it is a separate box. Most transformers offer more than one mode, so note which one yours is set to, not only what it can do.

• Countdown timer A number of hours — 2, 4, 6, 8, or a range such as 1 to 11. At dusk the photocell switches the lights on; the timer counts that many hours, then switches them off.
• Clock timer A time of day — a clock face, a dial with pins, or a digital display with a clock. The lights go off at the hour you set, say 11 p.m.
• Dusk to dawn Often marked D-D or D2D. No timer at all: the lights come on with the photocell at dusk and go off at first light.

What to change when the clocks go back

Countdown timer: nothing

The selected duration stays the same, but the clock time at which it ends moves with dusk. For example, six hours after a 5 p.m. start ends at 11 p.m. Review whether that duration still covers the hours you need; adjust it only using a mode supported by your model.

Clock timer: set it back one hour

A clock timer that does not adjust itself for daylight saving time will still be on summer time on Sunday morning, an hour ahead of every other clock in the house. Left alone, it turns the lights off at what it thinks is 11 p.m. and what is really 10. Set its clock back one hour: on a dial timer, turn the dial until the arrow points at the right time; on a digital one, use the clock button. If yours adjusts for daylight saving time on its own, look at it on Sunday evening anyway.

Dusk to dawn: nothing

In dusk-to-dawn mode, runtime follows the period of darkness and usually grows as winter nights lengthen. Check whether all-night lighting is appropriate for the location and how the sensor behaves in the installed position.

How to set it

1. Give the photocell a view of the sky. It should see the open evening sky, not a porch light, a streetlight or the glow of a window. A photocell that sees another light thinks it is still day and keeps the lights off; one buried in a shrub thinks it is night and turns them on early.
2. Pick a schedule. Choose the hours when people use the space. If your controller uses a countdown, observe its dusk start and select a suitable duration; a fixed bedtime such as 11 p.m. will not stay fixed across seasons without adjustment or a clock-based mode.
3. Test it. Cover the photocell with your hand or a piece of tape. The lights should come on, sometimes after a short delay. Uncover it and they should go off again.
4. Check it after a power cut. Some transformers keep their settings through an outage; an older dial timer loses its place and has to be set again.

A countdown timer through the year

A countdown keeps a duration, not a fixed bedtime. As a simple example, six hours from 5 p.m. ends at 11 p.m.; the same six hours from 8 p.m. ends at 2 a.m. These are illustrative start times, not sunset observations for a city.

A clock timer can keep a fixed switch-off time. Check its clock, daylight-saving setting, power-outage behavior and any separate switch-on setting according to its instructions.

Two schedules on one yard

One timer means one schedule for everything on the run. The walk lit until the last person is home and the trees off at ten is two schedules: a two-zone transformer with a timer for each zone, or two transformers. The transformer guide covers sizing each zone.