Secret Jardin - Cosmorrow LED 20W ULTRAVIOLET (L50)

The Cosmorrow ULTRAVIOLET is a waterproof 50 cm LED bar of 20 watts on 24 volts. It combines cool white light with UV diodes at 365 nanometres and is meant as a supplement.

Ultraviolet is a dose, not a setting

With ordinary grow light you think in intensity: more light means more growth, up to a point. Ultraviolet does not work that way. To a plant UV is a mild stress signal, and the effect you want comes from the amount received across a day rather than from where a knob is set.

What that signal does is well enough established to state. Plants under a little UV stay more compact and set shorter gaps between the nodes, they defend themselves more actively against mould on the leaf, and they produce more of the aromatic compounds many growers are after in the first place. That is why this bar gets added during flowering.

But it is stress, and too much stress is damage. A crop left too long under UV scorches at the leaf edges and grows more slowly rather than better. No single number holds for every room and every crop, so the safe approach is to build up: start with a short period each day, watch how your plants respond over a week, and only then extend.

Practically it therefore belongs on its own timer, separate from your main lamp, exactly as Secret Jardin themselves prescribe.

Technical Specifications:

• Model: col20uv
• Power: 20 W
• Length: 50 cm
• Spectrum: cool white combined with UV at 365 nm
• Application: supplementary lighting, on its own timer
• Supply voltage: 24 V
• Power supply: bought separately
• Protection: IP65
• Life expectancy: 50,000 hours

Frequently asked questions

How long should it run each day?
Start short and build up. No single figure suits every room, so watch how your crop responds.

Can UV damage my plants?
Yes, with over-long exposure. Scorched leaf edges and slower growth are the first signs.

Is it safe to look at?
Do not look into the lit bar and do not work for long under switched-on UV. Turn it off while you are in the room.

Can I run it alongside the infrared version?
Yes, but at separate times. They push the plant in opposite directions as far as stretch is concerned.

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