Lighting — Supplemental Lighting

Supplemental lighting does not replace your main lamp, it fills in where that one falls short. Which is almost always in two places: low down, where light from above no longer reaches, and in the spectrum, where an ordinary grow lamp has little to offer. So buy nothing here until you have a main light, because this is the layer on top of it.

Lighting the lower canopy

Light falls away quickly with distance, so the lower branches receive a fraction of what the tops do. The Cosmorrow bars from Secret Jardin, at 20 and 40 watts, are slim enough to hang vertically alongside the plant rather than above it, which is exactly what those lower branches need. The TNOLED versions do the same in a double fixture, and there is a 26 watt TLED for bloom.

Filling in the spectrum

The Cosmorrow comes as GROW, BLOOM, INFRARED and ULTRAVIOLET. GROW and BLOOM reinforce the stage you are in. INFRARED plays into the Emerson effect, where far-red alongside red yields more than either does alone. ULTRAVIOLET pushes the plant to build protective compounds in its leaves. From AC Infinity there are the IONBEAM U2 and U4 for ultraviolet and the S16 as a supplemental bar.

As a kit or separately

The Cosmorrow Kit Bloei supplies the bars at 60 or 100 watts with mounting and power together, which helps if you have nothing in this system yet. Buying bars separately, look under Power Supplies & Drivers: the Cosmorrow supplies come for one to five bars, and which you need follows from how many you hang.

Green light is for you, not the plant

The IONBEAM Green belongs in this group but serves a different purpose. Plants barely respond to green light, so you can use it to inspect during the dark period without disturbing flowering. It is the one light here you deliberately switch on while the rest is off. With ultraviolet, mind yourself: what pushes a plant to build protective compounds is not harmless to your eyes and skin either, so do not look into it or work under it for long.

Frequently asked questions

Can this replace my main lamp?
No. These fixtures are made to hang alongside a main light and do not give the coverage a tent needs.

How much do infrared or UV add?
That does not reduce to a single figure and depends on your lamp, your strain and your stage. Treat it as tuning at the margin rather than a step in yield you will see on the scales.

Do I need a separate power supply?
For the bars bought separately yes, and which one depends on the number. The kits include it.

Can I run UV all day?
Follow the figure on the product page. UV is used in short windows rather than as a second main light, and you do not want to be standing under it.