Hydroponic Light Timers, Meters & Controllers

Start with a timer

A timer is the bit of kit an indoor grow cannot skip. Plants read day length, and a flowering crop needs darkness that stays dark. Running the lights yourself works until you miss an evening, and one broken night is enough to put a flowering plant under real stress.

One fixture is what a basic plug-in timer is built for. A mechanical dial is the cheap, tough option — it only steps in 15-minute increments. A digital unit gives exact on and off times, more than one program a day, and it will usually remember those times after a power cut.

When you need a heavy-duty timer

The rating on a standard plug-in timer is one light. Several fixtures on the same switch push it past what the contacts can carry, and that is a fire risk rather than a nuisance. Multi-outlet timer boards and contactor boxes solve it by letting the timer trip a relay while the relay takes the load.

Past one or two fixtures, move up. Do not daisy-chain plug-in timers.

PAR meters — what light is actually reaching the plant

The coverage figure on a box is measured in ideal conditions. A PAR meter tells you what actually lands on the canopy — at your hanging height, inside your tent, off your walls. That is how you find out if a fixture is too high, too low, or leaving dark corners, and it is the useful number when you compare two lights or commission a new space.

Extendable wands sit next to the meters so you can walk readings across the canopy without leaning over the plants.

Controllers and dimmers

Fit a controller between the fixtures and the wall and you can dim several lights together, ease them up at sunrise and down at sunset, or change output as conditions shift. Hortivision, Digi-Lumen and Hi-Par each sell a brand-specific unit; multi-zone models run several fixtures on their own channels. Useful once you have more than one light. Pointless on a single fixture that already has a dimming knob. See the full LED grow light range for what they control.