+ 1200ppfd is it bad for ure plants

Hi there ,

As a solution to heat problems in my small 2x2 i bought this leds https://cre.science/en/shop/the-halo-fluxengine-x4/

At 40 cm in a 60x60cm grow tent it gives at center 1000-1200 ppfd .

My grow started with hps , and now im at day 20 of flowering and temperatures are hitting 28C, i need at least more 7 weeks and its
gonna get hotter as winter is ending .

The problem is plants stretched to much , and i can only place the leds at 30cm .

So are these 2 things a big no , no , changing from 250w hps to this leds , and placing them at 30cm that gives 1200+ppfd ?? Any help feedback is apreciated

bump

I had a pheno grow into 70,000 lux.

I can't help a dumbass plant. It's taken a beating. It also has about 15 days until it's dead. I did all I could to give it the best life possible.

It's neighbor plant has been at 47,000lux. Enjoying itself.


They're both getting smoked. I doubt Ill be able to tell the difference.

I wouldn't worry about the ppfd. The numbers reported by that site look to be extremely fabricated when compared to top of the line industry leaders such as HLG.

Just listen to your girls. They'll tell you if they're getting too much light. The stretching is probably from a lack of light honestly.

PPFD of full sun (meaning the maximum amount of sunlight we can receive on planet earth, e.g. on equator at noon) is around 2500 umol/m2/s

I get more stretch if the plants touch in veg. There's some kind of plant communication going on. They then compete for overhead space. Trying to grow taller then the other.

Regardless of light.

jimihendrix1 said:

PPFD of full sun (meaning the maximum amount of sunlight we can receive on planet earth, e.g. on equator at noon) is around 2500 umol/m2/s

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Thanks , what about the change from a hps to a much more powerfull light at 20 days in flowering u think they will be ok

Yep.
What Light?

SevenStoned said:

I wouldn't worry about the ppfd. The numbers reported by that site look to be extremely fabricated when compared to top of the line industry leaders such as HLG.

Just listen to your girls. They'll tell you if they're getting too much light. The stretching is probably from a lack of light honestly.

Click to expand...

They have twice the diodes then the top manufacturares , the numbers are right

Skyhound said:

Thanks , what about the change from a hps to a much more powerfull light at 20 days in flowering u think they will be ok

Click to expand...

They will be fine, just ease them into the new light if it's stronger. Start it out high, then lower it little by little until you hit your target height, just observe your plants for light burn/stress.

What light are you using?

jimihendrix1 said:

What light are you using?

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He's using a 320w LED with 560 smasung lm301h diodes.

Thats 80w sq/ft, and if its 320w of the best Samsung Diodes, and at 15.7 inches from the canopy, I fear for the plants lives. Thats 2x whats called for for LED growing, and is 9 inches closer to the top of the canopy vs what is normally recommended 2 feet for a Gavita 1700e

I use my Gavita 1700e as a guide and at 2 feet, in a 4 x 4 it will put out around 1000PPPF max.

OK. Now we take 320w, and put it in a 2 x 2 area, at 15.7 inches from the canopy????? Half the watts x 1/4th the area, 16 sq/ft vs 4 sq/ft ) and 2x the watts for the area, and 9 inches closer. And it only reads 1200PPPF at 15.7 inches??? Seems like it would read higher.

Can the light be dimmed? If not maybe switch back to the HPS to help keep hit down. That extra 70w might be enough of a difference to save ya

Dimmers are awesome

i have dimmer but i dont have lux meter i can only dim by feeling ? maybe to 75% , what u guys think

jimihendrix1 said:

Thats 80w sq/ft, and if its 320w of the best Samsung Diodes, and at 15.7 inches from the canopy, I fear for the plants lives. Thats 2x whats called for for LED growing, and is 9 inches closer to the top of the canopy vs what is normally recommended 2 feet for a Gavita 1700e

I use my Gavita 1700e as a guide and at 2 feet, in a 4 x 4 it will put out around 1000PPPF max.

OK. Now we take 320w, and put it in a 2 x 2 area, at 15.7 inches from the canopy????? Half the watts x 1/4th the area, 16 sq/ft vs 4 sq/ft ) and 2x the watts for the area, and 9 inches closer. And it only reads 1200PPPF at 15.7 inches??? Seems like it would read higher.

Click to expand...

its 170w led but yes at that distance it will be more then 1200ppfd

Tie the plants down if they’re showing light stress

jimihendrix1 said:

PPFD of full sun (meaning the maximum amount of sunlight we can receive on planet earth, e.g. on equator at noon) is around 2500 umol/m2/s

Click to expand...

A handy tool that not everyone knows about is the clear sky calculator. It is a digital tool developed by Apogee where we can see the light intensity pretty much anywhere on the planet, any time of the year and at any time of the day. It was developed so that their customers can calibrate their quantum sensors towards the sunlight, where they live. Handy!

I checked Bogota in Colombia which is located on the equator, which also seemed to experience more or less the same intensity as Yuma in Arizona.
At summer solstice, June 21, the PPFD touches just above 2000 for two hours.

Here are the rest of the hours for the same day and location, if anyone is interested in how strong the sun is at the brightest place on earth, at the brightest time of the year:

Military time - PPFD
01 - 0
02 - 0
03 - 0
04 - 0
05 - 0
06 - 0
07 - 128
08 - 531
09 - 973
10 - 1382
11 - 1718
12 - 1954
13 - 2071
14 - 2059
15 - 1920
16 - 1665
17 - 1313
18 - 895
19 - 453
20 - 56
21 - 0
22 - 0
23 - 0
24 - 0

Skyhound said:

i have dimmer but i dont have lux meter i can only dim by feeling ? maybe to 75% , what u guys think

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You need to buy a lux meter then; they are only 20-$30 and you can easily convert to PAR by dividing by ~68. You will also now be using that dimming function and be able to adjust for the life stages of the plant. There are also apps for your smartphone but they tend to suck at higher lumens.