Light
meter: Useful for determining whether light levels are adequate
throughout the garden, and for routinely checking if lights are operating
to specification (Fig 10.6).
Compatibility: Ensure the
ballast and lamp suit one another. For example, lamps of different
type (e.g. MH or HPS) or different sizes (wattages) may require a specific
ballast. Also, if using an ‘electronic’ ballast ensure the lamp is
compatible (i.e. otherwise causes premature lamp failure, blackening,
etc).
Handling HID lamps: Lamps can
explode if they are cold when lit or have fingerprints on glass.
Always wrap in clean paper/ or towel before handling. To clean the
lamp glass use window cleaner (or rubbing alcohol) and allow to dry
thoroughly before use. Lamps should not be restarted immediately
after being switched off (MH lamps should generally be left off for at
least 20 minutes; HPS for at least 3 minutes).
Effective working life: A lamp’s
intensity will diminish with use, and may also use more power. Note
that MH lamps have a shorter effective working life than HPS. Also
note that the capacitor in magnetic ballasts will deteriorate with use and
consequently the light intensity will diminish. Ask the manufacturer
for the useful working life of these items.
Lamp orientation: Lamp
directions will specify whether a lamp can be orientated vertically,
horizontally, etc. Failure to comply can cause poor lumen or colour
output, and shorten the lamp’s life span.
Electricity: Note, HID lamps draw large amounts of electricity
therefore safety must be a priority.
