Lumatek light overdose?

[OGDread]

Ladies and gents,

Whats going on:
I have something that I only can describe as a light overdose. Too much lumens... two weeks ago 1 replaced a 400watt bulb in the center, for a 600 watt lumatek. It had a pretty obvious light pattern, as the hood was also new, and still sharply bend.

Now two weeks later, the plants in the middle have yellow leaves on top, right below is lot greener, and just few yellow leaves very low.

What I have done:
Afraid of N shortage, i give low dosages in bloom, I gave a high N dosage last night.
I also raised lights, especially the middle one.
I swapped the most effected bag, with the least effected.

Have i done right? Is this whats going on? Any suggestions?


Situation, 3 x 600watt side by side, covering 3m2

as an expiriment, Im also mixing my containers, like this:

left light
left side, 2 rows of 4 plants (8), right side, 1 bag of 50L with 6 plants and 2 pots 11L in front. (8)

Middle light
2 bags 50L with 6 plants each, 4 pots of 11L in the front.

Right light
left side 1 bag, 6 plants 2 Pots in front, 2 rows of 4 pots on the right side.

So 4 bags, with pots surrounding the left front and right side...

This is the middle lamp, you can see the coloration, wich matches the light pattern exactly..

From a distance you can see the yellow area

Here I placed the the most effected bag, the right one under the middle light, to the far left position. Its pretty obvious thats its not just a light pattern anymore!

here are some leaves, the yellow areas were directly exposed to the light.

Here some healthy, just to show off, mix seeds, 2 weeks bloom, cinderella 99 4 weeks bloom, same room, same nutes

Here is the questionaire

How long has this problem been going on?
looks like 2 weeks

What STRAIN are you growing?
Widow/afghan

What was the establishing technique? (seed or clone?)
clone

What is the age of your plants?
7 weeks from received clone

How long have they been in the soil mixture they are in now?
4 weeks

How Tall are the plants?
30-40cm

What PHASE (seedling, vegetative or flower) are the plants in?
bloom, week 4

What Technique are you using? (SOG, SCROG etc)
sog, 16/m2 trained for multiple bud

What size pots are you using? (Include how many subjects to pot)
bags: 50L 6 plants
pots, 11L 1 plant

What substrate/medium are you using? What brand of soil mixture are you using?(percentage of perlite, vermiculite...etc?)
100% Biobizz allmix

What Nutrient's are you using?
Biobizz grow/bloom/topmax

How much of each nutrient are you using with how much water? *Knowing the brand is very helpful*
50ml/10L of those 3

How often are you feeding?
Once a day

If flowering, when did you switch over to using Bloom nutrients?
2nd week of flower

What order are you mixing your nutrients? (example: veg nutes 1st, bloom 2nd ect)
er... that may vary

What is the TDS/EC/PPM of your nutrients used?
unmeasured

What is the pH of the "RUN-OFF"?
about 7

What method of pH test was administered? Using Strips? pH pen?
pen

How often are you watering?
Once a day

When was your last feeding and how often are you feeding?
Today, Once a day

What size bulb are you using?
600watts

What is the distance to the canopy?
first 50, now 60cm...

What is your RH Factor? (Relative Humidity)
between 50-65

What is the canopy temperature?
night 21, day 29

What is the Day/Night Temp? (Include fluctuation range)
20-29

What is the current Air Flow? (cfm etc.)
1500m2 out, passive in

Tell us about your ventilation, intake exhaust and when its running and not running ?
Intake is passive, partly from outside (15cm tube) rest from inside, crawlspace

Is the fan blowing directly at plants?
3 fans, blowing at the lights, perhaps touching the tops

Is the grow substrate constantly wet or moist?
pretty dried out in the morning

Is your water HARD or SOFT?
hard, 7.8

What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water?
Dutch tap

Are you using water from a water softener?
nope

Has plant been recently pruned, cloned or pinched?
nope

Have any pest chemicals been used? If so what and when?
in veg a dose of bayer masai

Are plant's infected with pest's?
nope

 

[Arlen]

I'm no expert but those leaves look hungry to me.

 

[OGDread]

Could it be Im short on nutes (n mostly then) and it effecting only the leaves getting blasted in light?

a few side by side

 

[HeadyPete]

It's not burn, thankfully.

What I suspect has happened here is that when you changed the 400 for a 600, the plants under that light are all of a sudden receiving more light energy, therefore the metabolism kicked up and the plant started eating more. That looks like a nute deficiency on those plants.

What is the ph of the nute solution after mixing?

Around 7 is too high, it should be that nute in and runoff = around 6.3-6.5. You may need to drop nute ph lower until the runoff starts coming down, then raise until 6.5 in = 6.5 out. Make all ph changes gradually, over days, .1 point at a time. Plants do not like sudden ph swings.

All in all they look great, so don't stress that there is a major problem here.

Biobizz has a feed sched that gives week to week suggestions of dose. I would go easier than they suggest at first to see how they react and remember there is nutes in that AllMix as well.

 

[OGDread]

Thanks a lot for the replies.
I recalibrated the meter and I measured the water again, 7.8 plain tap (sometimes it gets as high as 8.3...)
7.1 mixed
7.0 runoff

I dont use ph-, I find it hard to keep the levels constant, and I may end up doing more harm then good.
ps., I use the biobizz schedule, about 3/4 recomended bloom verts, and 1/2 grow. I switched to 100% recommended grow now.

 

[HeadyPete]

You should bring down your fert/water mix to 6.5 slowly with PH down. You are doing more harm than good now with a high ph. Tap also takes time before the ph settles down due to the minerals in the water. When you add ferts those minerals bind up with the ferts and adjusting ph is easier. Plain tap takes longer for the chemical reactions of the acid and the cal and mag in the water. Let it mix for an hour before reading ph.

Sounds good on the BB sched, although I find the Grow to be low in P for vegging moms long term. I mix it 1/2 gro 1/2 bloom.

 

[Weedhound]

I agree....a lower ph both going and in the runoff would be better for your plants.

 

[OGDread]

ok, so my goal is to lower the mix in .1 per day, to 6.5, and see what the runoff turns into

Can I add the (phosphor) ph- right after the nutes, just before watering, or will that just be wildly off?

 

[HeadyPete]

yep, ph down last and mix well.

 

[OGDread]

HeadyPete, supercalifraciousthanks

 

[whodair]

my 600 lumatek hortilux is on the shelf

my 600 lumatek hortilux is on the shelf

had the same problem, and went back to my 430w hps. in my environment, the girls reacted better to that wattage and spectrum. also my palnts off to the side always crystallize more. the angle of the rays may be more like fall along the edge of the garden, where the angle of the rays is more direct in the middle of the patch. i dont know if that makes sense

 

[NWestCoast]

my 600's can do the same when they get too close, so can 1000's. You have a deficiency as already stated. Light burnt plants bleach uniformly and then get crispy.

 

[NWestCoast]

Also, you will know when your plants are healthily regrowing and you have fixed the problem when the inner growth leaf (new growth) has greened up again.

Have you tried raising the light to see if it fixes the problem? You have to start eliminating possible causes somewhere for your own reference. Experience is the best teacher.

 

[OGDread]

Whodair: it does make some sense. My most effected plants actually get light from the center lumatek, and the light next to it. In the dead center of the middle light is actually some shadow, the hood misses that spot (there is no sharp triangle bend down in the centre of the hood, like some have)
NWC: yes, I have raised the lights 3 inches about, I dont expect much new growth however, its about 32 days bloom. Next week, it basically shoudnt be worse