Supplemental LED Lighting

Supplemental LED lighting is added alongside a main fixture rather than instead of it. Two very different jobs sit under this heading: adding a spectrum your main light does not produce, and getting light into parts of the canopy the main fixture cannot reach.

Spectrum supplements

• Far red (730nm). Triggers the shade-avoidance response and is used at lights-off to shorten the transition to darkness. Some growers run a short far-red burst at the end of the photoperiod.
• UV-A and UV-B. Used in the last weeks of flower. The plant produces protective compounds in response, which is where the interest in resin and aroma comes from. Handle with care – UV damages eyes and skin, so proper glasses and short exposure windows matter. See UV lighting.
• Deep red and blue bars for tuning a fixed-spectrum fixture.

Side and under-canopy lighting

A top-down fixture loses intensity fast as it travels down through the canopy, so lower sites stay small and airy. Bars mounted at the sides or below fill that in. Worth it if you are running a dense canopy or tall plants; pointless in a short, well-trained one where light already reaches the whole plant. See under canopy grow lights.

Be honest about whether you need it

Supplemental lighting is a refinement, not a fix. If your main fixture is undersized, or your environment is off, adding a UV bar will not help – you will just have an underlit room with a UV bar in it. Get the main light, temperature, humidity and feed right first, then add spectrum. Browse LED grow lights and grow room lights for the primary fixture.

Why buy from The Hydro Bros?

We are a hydroponics shop in Croydon and we will tell you if your room is not ready for this yet. Discreet UK and European delivery, and excellent customer reviews on Trustpilot.