On Sun, 23 Jul 2017 10:08:32 +0100, Martin Brown
wrote:

On 23/07/2017 00:20, Archibald Tarquin Blenkinsopp wrote:
Anyone used one of these?

I thought I would give one a go, 900W [presumably effective LED power]

As the mains power is 120W I assume it's the equivalent wattage of a
sodium lamp of similar luminosity?

Out of curiosity what colour is it? The professional LED grow lights
these days omit the green LEDs almost entirely and so appear magenta. No
point producing light that simply reflects off chlorophyll.

and the rest of the stuff only shows a marginal improvement over the
"control" plants in a south facing window.

It is mid summer and it would be surprising if things on a sunny window
sill did not thrive.

I power up the light for eight hours. I switch on when I get home in
the evening and off in the morning.

Depriving them of the night time cycle - which might be OK for some
plants that live at high latitudes but would be disastrous for desert
plants using C4 acid metabolism which only breath in the dark at night.

The room is lit with daylight from a curtained window also.

The light does not seem to be worth the power expended on it, but is
it worth keeping for when the days shorten?

Depends what you are trying to grow and how much light they need. If you
are trying to grow things year round and not have them go leggy in mid
winter then the grow light will do what it is intended to do.

Has anyone any tips or suggestions please?

AB

Use the grow light to supplement dark days - don't use it to deprive the
plants of their daily light cycle (unless you are doing it to trick
something into flowering at eg Christmas).

Thank you. I jumped into a subject I knew nothing about, with nothing
but ignorance and a few spare pounds.

The light is being shelved and the plants are going on the shed roof.

In the meantime I'll read a book or two.

Regards

AB