Is this nute burn or light burn?

First grow, in flower, day 10 in photos since 12/12 switch. I believe this is Nute Burn but the Mars hydro website has changed the height suggestions of their lights in the last 2 months. My ladies are stretching fast. Mars says my 300watt tsl2000 can be 12" without CO2 at 100% (last month it said 16-24"). I’ve got it up to 22in at the moment in case it’s lightburn not Nute burn. Had them at 14-16"s first 5 days and noticed these tips changing (18" all veg). Tupar coco mix, Fox Farm Hydro Trio pack at about 66% strength, 175%ish cal-mag & using distilled water. I’ve had calmag deficiency issues start & fixed couple times throughout the grow, these ladies want the extra. Plus they really don’t like it if the pH gets too many feedings below 6.0 (they seem to prefer 6.2-3ish). Any advice welcomed!



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Forgot to say Lights on average temp 80F/ RH 55-60%, lights off avg. 76F / RH 50-55%.

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Looks very healthy. What leads you to believe the plant may be burned by something?

Your pH target should be 6.5.

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Thank you for the healthy compliment. If you look closely at the tips you’ll see slight “burned tip” Alil yellowed and slight bend in a few. It’s subtle still but I wanna nip it in the bud right away.

You have minor tip burn…
Nutrients are at optimum levels…
Stay right where you are…
Dosen’t look like light burn…
If things start to get worse, back off of the nutrients just a little…
You could also raise the lights just a little if necessary…
:v:t4: :sunglasses:

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Those are flowering pistils developing. Your plant is perfectly healthy.

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In coco perlite mix medium most “experts” say to treat it like straight hydro with ph’s starting at 5.5-6.5. My Amensia Fast ladies definetly don’t like it low however. Now I make my feeds to @ 6.0 and let it drift to @ 6.4 ( I make @ 4 days feed at a time)

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Okay. I missed that you were in coco. Here’s the pH profile for hydro/coco.

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Thanx for your thoughts :slight_smile: I’ve rread some growers like to take it just to the begining of nute burn (like here it seems) to make sure their geting everything they could need. I’l try and make the next feed bucket a little bit lighter nutes but not much.

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Periodic flushing is recommended in coco. A product like Florakleen or Sledgehammer can help too. I monitor runoff TDS and when it drops below about 1,200 ppm in coco it’s time to supplement. If it’s above that value it either gets a flush or water-only until the value drops to my target then resume feeding. This can help with any nutrient excess or lockout due to it.

Plant looks good from what I can see.

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I’ll give them a flush today and probably tomorrow. They drink about half a gallon a day, 3 gallon fabric pots. I’m assuming I make ph balanced water and still add the appropriate cal-mag right? Thanks again for everybody’s responses

Just use whatever water you currently use, monitor runoff until it drops below target value.

You can even use the water from the tap then finish with a final gallon of PH’d and Cal Mag’ed water.

I did a quick DLI calc on your light
PPFD map from mars site


Based on this I would not think it is light burn if you are in a 2x4.
I do want to point out though, at 12 hours and at 18" the DLI is about 27.
With the light at 22" the DLI will be quite a bit less. During flower 27 is on the low end of desired DLI
DLI Screen-Shot-2018-12-28-at-11.19.14-AM

I think Amnesia Haze is a pH sensitive strain. Good that you recognized that and made adjustments to find the sweet spot. I think the plants look healthy. For me, if my plants don’t have a little tip burn they are being under fed.

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Amnesia haze is also a strain that is hungry for magnesium that fox farms and calmag cannot supply. Not seeing a mag def yet but come flower it will occur. Recommend some plain epsom salt for your plant come flower. Start with 1/4 tsp/ gallon on water only days.

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Thanks for the very specific info, boy everyday I have to learn something new LOL. DLI is one I have not looked into yet. So it sounds like you’re saying I want to keep it as close to 18 and maybe even lower? The Mars site does show in a recent update that they now recommend 12"s at 100% in flower without Co2 supplement. It seemed too close for my taste and in turn I misread it seems this slight nute burn for lightburn. Now that I’m adjusting the Nute Burn, which already looks better today, I’m going to let it grow into the light before I move it up again, maybe 16"?

Around 16" sounds about right. The important thing is you are letting the plants tell you where they max out. One thing about having a light set at lower heights is the intensity at the perimeters drop significantly. Generally, if Mars is saying 12 is an acceptable height, I take it they are maximizing PPFD directly under the light and as you move out from the center the PPFD drops. Therefore, the size of your space has a lot to say about the best height for all of your plants in that space. So it is finding the balance of maximizing intensity and therefore bud quality while not burning them while also optimizing it’s intensity over the entire space.

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I would say light stress