Bleaching leads to purple? with pics

I mentioned before that the plant directly under the centre of my lamp seemed badly bleached
(the outer plants are a rich, deep blue/green)
the central plant - and some of the stems from neighbouring plants - that also fall under the centre of the lamp
are more of a lime green.
And they seem more dried out, less healthy, less vitality.....

Now the trim leaves of the central plants/stems are developing purple.
The outer plants are not.
Pics of both are uploaded for comparison
The first 2 pics are central
the 3rd is a corner plant.

(be aware these pics are taken with an old mobile phone camera -
so aspiring photography critics can just fuck off to another thread)

Cheers

Looks very similar to heat/light stress. It shouldn't cause purpling directly, but indirectly it can because heat stress can lead to deficiencies which would cause the purple. Based on how good the corner plant looks heat/light stress would definitely be my guess, especially since your description matches most of the symptoms.

Purple patches on the leaves Phosphorus deficiency. Pic 2
Pic 1 looks like a (P) def. and a Magnesium def.
as to why? you'll have to make sure everything is where it should be, pH, soil temps, your feeding schedule. over watering.
Keep in mind marijuana loves Phosphorus.

Good Luck on Your Grow.

topfuel29 said:

Purple patches on the leaves Phosphorus deficiency. Pic 2
Pic 1 looks like a (P) def. and a Magnesium def.
as to why? you'll have to make sure everything is where it should be, pH, soil temps, your feeding schedule. over watering.
Keep in mind marijuana loves Phosphorus.

Good Luck on Your Grow.

Click to expand...

I cannot imagine it being a deficiency because all 9 plants are fed from the same reservoir on the same schedule.

I upped the light from 600w to 1000w and the plant in the centre - plus the stems of the neighbouring plants that are also situated in the centre-
became 'bleached' looking.
(It's my first crop so I'm half guessing but the 'bleached' parts looked almost a lime green, rather than the rich, deep blue/green of the corner plants.
When the light first goes off the bleached leaves seem to glow - like they're retaining energy.
They have a fluorescent quality to them. If that makes any sense???).

I have little choice other than to carry on to the finish, with these 9.
But I have 23 Clones on Day 9 of Vegetative 18/6 growth and I'd like to avoid repeating any mistakes.

I was considering using PK13/14 and Mag supplement from week 5 of Flowering - on the next crop.

But I am unsure of whether to reduce the light power???
I have a dimmable Lumatek 1000w - so taking it to 600w or 750w is easy
I could even boost it up to 1100w

Taking the reflector higher is an option....
but then I worry about stretchy, lanky plants???

SUGGESTIONS PLEASE....????????

Its not a deficiency. You are correct it is bleaching. The discoloration is likely just a side effect of the bleaching and disruption caused by it. Dimming a bulb is hard on it. You are better off to either raise the light or get a lower wattage bulb to match with a lower setting.

Alexander Supertramp said:

Its not a deficiency. You are correct it is bleaching. The discoloration is likely just a side effect of the bleaching and disruption caused by it. Dimming a bulb is hard on it. You are better off to either raise the light or get a lower wattage bulb to match with a lower setting.

Click to expand...

If I dimmed the ballast to 600w I'd put a 600w bulb in.
At 1000w the 1000w bulb goes in.
It's the 750w and 1100w settings that are difficult.

As yet I haven't used them.

The 10% over can be used at anytime with a 1000 watt bulb. But most only use it with an older bulb to get a bit more life out of it. And they do make 750 watt bulbs.

edit: also there is no need to keep a 1000 watt light any closer than 32-36 from the top of the canopy. You should probably research 'plant light saturation'.