Developed a huge problem over night

Plant: Green Gelato
Soil: canna 70/30
lights Viperspectre 350w LED at 16 inch during flowering.
Feed Biobizz bloom once a week, followed biobizz feeding plan. cal mag once a week.
lights 12/12
Humidity is been fluctuating between 50 and 65%
I'm 5 weeks into flowering and everything was going swimmingly, Thursday night last, fed them their usual Biobizz but also installed 2 x 120 watt full spectrum LED's because of two dead spots I had in the lighting and stunted buds in those areas.
Friday night all was well and LEDS were set at 16 inch same as Viperspectre.
Saturday night, opened the grow room to a disaster, 75% of the bud sights seemed fried and dried out with what looked like bleaching of the sugar leaves, Took a bud that was badly affected and cut through it to see if any grey mould or brown mould but all nice and green but plants look like they've symptoms of bud rot but no actual bud rot. Top 2 inches of colas crumple in your hand like dust, really dry.

What are your temps with the new lights?

Herb & Suds said:

What are your temps with the new lights?

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Temps are 77 with old lights and 79 with new lights on, also have 3 fans running and 4 inch extractor fan

What’s the humidity. Are you certain on the temps

Yes temps are spot on, gauged digitally with sensor inside grow room, done successful grows before in same environment. We're experiencing humidity fluctuations recently due to heavy rain then dry spells and has been fluctuating between 50 and 65% but friday and sat were a little lower at 45%. The problem seems to have happened inside a 24 hour period with 75% of buds affected. The other buds not affected are clean and healthy. Done a flush in case nute salts have built up and been affected by extra lighting and sprayed affected buds with a cal mag mist to see if I can get life back in. Never seen anything so devastating so quickly.

Also removed new lights

Gotta blame the only change, the new lights. They maybe too old to be introducing new things. May have just up'd the light intensity too much. The extra light could have caused then to draw too much of a certain nute and caused that burn. I see that u removed them, so you should be fine. I would go light on the nutes for a bit in case it's the last thing that I mentioned.

These were the same plants thursday night, so much devastation in such a short period. Definitely had a shock to their system and like you say they could have tried to draw a lot of calcium to combat the extra light and burned them. I've removed the light and flushed then done a foliage misting of calmag to dry and get some life back in there. Devastated.

I have heard of cheap plastic lens that distort the light as it pass through them and can cause hot spots and burn area... works like a magnifying glass

Magicbeanz007 said:

I have heard of cheap plastic lens that distort the light as it pass through them and can cause hot spots and burn area... works like a magnifying glass

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Actually these lights do have plastic lens on.

Sending the bulbs back for a swap with bulbs with no plastic lenses in. It's kind of obvious what's happened now, thanks all, just hope I can recover them.

Recovered the plants and harvested, down in THC but very nice.