Too much light

[pending]

I've looked at some of the other posts on too much light and maybe I'm looking at it wrong.. I thought it was a minimum distance question.. what's the min dis that the light saturation was sufficient for flowering.. the prob with bigger wattages was heat stress inside a certain distance.. anyway.. My question goes as so.. Kicked my light up to 1000watts testing the rooms temperature and after a couple of hours got it down into the mid seventies within a degree of what it was running at at 750watts.. I was happy.. Now, not so much.. My leaves seem to be coming in smaller.. Existing leaves lost some girth.. My lights about three feet above the plants.. The plants are sitting 16 inches off the floor.. I turned my lights back too 12\12 today, it's the reason for the testing.. should I go back to 750w when I swap over to the HPS or just put the plants on the floor now.. The room is 5/5, 25sq ft with 16inches of space above the light so I've got plenty of room.. thanks laters

 

[skirk]

@pending,What is the make and model of your light?

 

[pending]

IPOWER 1000watt variable me thinks.. I really thought the light was further away from my plants.. Was fine at 750 watts.. Doing a temp check before flowering and forgot\misjudged distance the light was from the plants.. Never meant to be any closer than 4 feet.. Don't know why, no idea where I pulled that number from..

 

[pending]

I dropped the plants a foot more or less, still five inches off the floor.. Dropped the power back to 750watts & turned a fan off that forced air into the room.. Can't say what was talking the shine off the leaves and causing them stress but I guessed right.. Leaves are banging and going passive with the air actually dropped the temperature of the room 2 to 3 degrees.. laters

 

[Mayne]

HEAT HEAT HEAT

I took 2 week old plants, under 1000 par, 3 inches from the light (ViparSpectra) and as long as it was cool air, they loved it. no burn, no crinkle, nothing.

 

[pending]

I dropped the plants a foot more or less, still five inches off the floor.. Dropped the power back to 750watts & turned a fan off that forced air into the room.. Can't say what was talking the shine off the leaves and causing them stress but I guessed right.. Leaves are banging and going passive with the air actually dropped the temperature of the room 2 to 3 degrees.. laters

Gotta love living in the south.. It's not the heat it's the humidity.. Note to self.. Passive air intake in lower Alabama equals powdery mildew.. FFS I can't catch a break..

 

[sstressed]

Speaking of too much light - I went into the hospital for a 4 day stay (it was nothing). My crop was ready to flip into flower but I made a quick decision to just use the 60ish watt light in my closet. I had no idea it would be 4 days of testing. I get home, turn on the 1000 watt,, put it up maybe 5 feet over the canopy (it was a great closet). Went to work. 11 hours later, the plants leaves (12 plants) were all dead. every beautiful green leaf was dead brown and some were a bit crispy. I called it light shock. I almost ran out of bud before my next crop.

 

[Stunned]

Speaking of too much light - I went into the hospital for a 4 day stay (it was nothing). My crop was ready to flip into flower but I made a quick decision to just use the 60ish watt light in my closet. I had no idea it would be 4 days of testing. I get home, turn on the 1000 watt,, put it up maybe 5 feet over the canopy (it was a great closet). Went to work. 11 hours later, the plants leaves (12 plants) were all dead. every beautiful green leaf was dead brown and some were a bit crispy. I called it light shock. I almost ran out of bud before my next crop.

Well done......

 

[LoSBigBlue]

Get the Photone App for your phone, if you have an Apple phone it has been tested for accuracy against $500 light meters and is very accurate. The Android version will also work, it is not accurate but it is consistent with its inaccuracy meaning you can multiple by a factor to get accurate values.

Having this at your disposal will allow you to know PAR and DLI values and to adjust your lights to those values. There are plenty of guides that give recommended values for different stages of growth.

 

[Hybridway22]

I've looked at some of the other posts on too much light and maybe I'm looking at it wrong.. I thought it was a minimum distance question.. what's the min dis that the light saturation was sufficient for flowering.. the prob with bigger wattages was heat stress inside a certain distance.. anyway.. My question goes as so.. Kicked my light up to 1000watts testing the rooms temperature and after a couple of hours got it down into the mid seventies within a degree of what it was running at at 750watts.. I was happy.. Now, not so much.. My leaves seem to be coming in smaller.. Existing leaves lost some girth.. My lights about three feet above the plants.. The plants are sitting 16 inches off the floor.. I turned my lights back too 12\12 today, it's the reason for the testing.. should I go back to 750w when I swap over to the HPS or just put the plants on the floor now.. The room is 5/5, 25sq ft with 16inches of space above the light so I've got plenty of room.. thanks laters

Hello! The saturation point in which negative effects kicks in is dependent on your spectrum. In general cannabis has a 1750 umol outdoor saturation point. With a well balanced spectrum, artificial leds can go to about 1500 umol although nobody recommends over 1250 usually because they hit the point of diminishing returns & or negative effects on their plants. Many making the switch make the mistake of using to much light, not realizing their spectrum may be Defficient & that likely their laser pointed led is putting out twice the photons to the canopy then hps. One reason why hps plants are easier to grow. Their peak ppfd's are usually 650ish whereas with a bar light one could easily provide 1200 ppfd of even coverage. Going from hps/mh or low lit veg to these kindve #'s will make your plant freak out usually. That is why I tell growers "Less is more" with led until your dialed in & used to the transitional phase. Which is actually the most important to maintain success.
Try increasing veg intensities prior to entering flower, then when entering the flower area, raise your lights to the Roof. Put them at a decreased power level & increase it over the course of a week or have it up there on high & let the plants grow up into it. The farther away the better off you are until your plants adapt.
If using a QB style light & it contains a very tight cluster of white leds then I'd consider diffusion & supplemental..
Goodluck!