hps to led problems

hi all, after years of hps i decided to buy a led 720w ,so i have 2 wilma systems side by side, one with 600 hps and the other using my new led 720w
they a both 4 weeks into flower,and both getting tret exactly the same ,nutes,watering times etc
the plants under the hps are fine,and looking really healthy,but the ones under the led light are looking a little lime green and a bit veiny
could anyone help im 4 weeks in to flower,they are not in tents,but both in the same room
il try and get sum pics

Pictures would help
What make and model is the 720 watt led light?
How close are the lights to the canopy?
720 watts of led is going to be the equivalent to ~ 1000 watts HPS.

^ yup. Sounds like just a bit too much light for the plants. Also look at the plants under the same light to make sure what you are seeing is not because of the different colour light.

It could also be the LEDs aren't heating the leaf surfaces and the lower transpiration of the plants is reducing nutrient uptake.

You can check your canopy PPFD with a free app like Photon, 800-1100 is usually the sweet spot for flowering.

Lower heat, LEDs should be 8"-24" depending on strength and growth period. People are finding that LEDs make your plant go through more cal/mag, too.

For heat when I need it, I have a small USB fan blowing down from the lamp onto the plant. Push some of that driver heat down.

HPS fan here.

Mix and match?
Folks can say that HPS is your grandfather's grow lights but they sure have their positives.
I dono, my design for the flower room has HPS augmented with Corn Cob LED

I mean we are simulating the Sun after all.
Good reading from those in the know in this thread so I thank you.

Dirt_McGirrt said:

Lower heat, LEDs should be 8"-24" depending on strength and growth period. People are finding that LEDs make your plant go through more cal/mag, too.

For heat when I need it, I have a small USB fan blowing down from the lamp onto the plant. Push some of that driver heat down.

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My personal hunch....I think LEDs may slow nutrient uptake and the Cal/Mg issues show first.

Only one I've had issues with is cal/mag. I'm in coco with distilled water, too. So there's that. Running ol reliable GH.

I actually have a mg foliar coming and trying that.

Dirt_McGirrt said:

I actually have a mg foliar coming and trying that.

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What do you mean a Mg foliar coming? Go down to the store and get a bag of Epsom Salts for $5.

Friendly_Grower said:

I mean we are simulating the Sun after all.
Good reading from those in the know in this thread so I thank you.

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Nah. I really do not want sunlight in my tent.

xtsho said:

What do you mean a Mg foliar coming? Go down to the store and get a bag of Epsom Salts for $5.

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But the foliar is specifically for weed bro

Horselover fat said:

Nah. I really do not want sunlight in my tent.

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Tent?

xtsho said:

What do you mean a Mg foliar coming? Go down to the store and get a bag of Epsom Salts for $5.

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Oh. Well alright then Epsom salt it is. Just found the ratio.

madas26 said:

hi all, after years of hps i decided to buy a led 720w ,so i have 2 wilma systems side by side, one with 600 hps and the other using my new led 720w
they a both 4 weeks into flower,and both getting tret exactly the same ,nutes,watering times etc
the plants under the hps are fine,and looking really healthy,but the ones under the led light are looking a little lime green and a bit veiny
could anyone help im 4 weeks in to flower,they are not in tents,but both in the same room
il try and get sum pics

Click to expand...

Give us more detail.

Space each light is covering.
Light distance from canopy.
Brand and model or type of light.
Air temp
Nutrient strength.
Ph

And yeah, pics would help

You probably don't need a foliar of anything.

7CardBud said:

My personal hunch....I think LEDs may slow nutrient uptake and the Cal/Mg issues show first.

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It is a personal hunch and not based on science

Led growers (on the internet) be like:

1) Dark plants are awesome, needs more calnit, pk boosters bad! Borax bad!

2) It's so frosty, look at all the calcium carbonate in the trichs. Much frostier under my led smartphone flash than silica trichs.


3) I prefer smoking the lower, shaded buds. I also take photos of lower buds because my tops are too fucked up.


4) I love all the dumb shit the experts say, but when NASA scientist Bruce Bugbee said Cannabis soaks up Calcium like a sponge and struggles to uptake potassium, I'm gonna ignore that, because we all know led plants need more calcium. Someone told me so. It's even written in the broken English spider farmer manual. They've never grown a plant, but the plastic plants in their photos look nice?

GrodanLightfoot said:

Led growers (on the internet) be like:

1) Dark plants are awesome, needs more calnit, pk boosters bad! Borax bad!

2) It's so frosty, look at all the calcium carbonate in the trichs. Much frostier under my led smartphone flash than silica trichs.


3) I prefer smoking the lower, shaded buds. I also take photos of lower buds because my tops are too fucked up.


4) I love all the dumb shit the experts say, but when NASA scientist Bruce Bugbee said Cannabis soaks up Calcium like a sponge and struggles to uptake potassium, I'm gonna ignore that, because we all know led plants need more calcium. Someone told me so. It's even written in the broken English spider farmer manual. They've never grown a plant, but the plastic plants in their photos look nice?

Click to expand...

You know what’s even better? Some noob who joined 2 months ago criticizing everyone else’s grows and hasn’t even posted a pic of his mids yet.

bk78 said:

You know what’s even better? Some noob who joined 2 months ago criticizing everyone else’s grows and hasn’t even posted a pic of his mids yet.

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don't forget the blaming on everything on lack of boron when literally nobody has a boron deficiency