Auto seedling looking sick..Nutrient deficiency or light burn?

Hi all, hope everyone is well. Been a couple months since my last grow so I'm a bit rusty. I'm growing an Auto in coco perlite, run to waste, 200 watt spider farmer led at 70% power 61cm from plant which is what the manufacturer recommends. Feeding at pH: 5.9 PPM: 250 Temp: 20 degrees Celsius. Tent temp stays around 22 to 23 Celsius & humidity is a bit low between 50% to 65%. Strain is called "secret high cbd strain" & it does say its a moderately hard one to grow. I'm trying a new nutrient called cronk nutrients that is meant to be specifically for autoflowers, I've added calmag past 2 waterings to the base nutrient. I've gotten it to week 2 but now it's looking very light green with a brown spot on the tip of one of the leaves and the new growth has black bits on the tips, the leaves seem a bit limp too. It did stretch quite a bit at first so I burried the stem & lowered the light. I took pics with LEDs on, all lights off & with camera flash on so hopefully someone knows what's going on. I did google it but couldn't get any good answers to the problem, someone else did seem to have the same problem but didn't get any answer in the end. If anyone could help me out a bit that would be great, thanks very much in advance

Is that 250ppm including your base water ppm?

Looks hungry! I don’t grow in coco but you need to add nutrients in every feed to the media and 250 doesn’t look enough!

Hopefully someone who knows coco will chime in

Increase the Nitrogen dose a little bit. Other than that, the plant seems to be looking ok.

Made for specifically for autoflowers.

7CardBud said:

Made for specifically for autoflowers.

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I've heard a lot of myths about autos but nutes specifically for autos is a new one.

It's all the same 16 (or 18 ) chemicals. Some come in pretty bottles, some are in bags but it's all the same 16 (or 18 ) chemicals.

This really sucks to figure bc new growth is often lighter green anyways, but I noticed it's more your 2nd and 3rd node that are most affected. Just looking at this chart..sulphur deficiency looks the closest match.

Honestly shocked your having issues with it so young. I do t even feed nutes till the 3rd node bc I've been taught/read that a seed has enough nutes/energy to make it to 3rd node with just water.

bignugs68 said:

This really sucks to figure bc new growth is often lighter green anyways, but I noticed it's more your 2nd and 3rd node that are most affected. Just looking at this chart..sulphur deficiency looks the closest match.

Honestly shocked your having issues with it so young. I do t even feed nutes till the 3rd node bc I've been taught/read that a seed has enough nutes/energy to make it to 3rd node with just water.

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He’s in coco which is inert. 3rd node on just water is growing in soil

Have a look at coco for cannibas online , I learnt everything about growing with coco there and it's all really good info I use coco for autos sometimes but have been sticking with a peat based medium . That plant needs food have a look and you'll be able to come up with a nutrient regime. In coco I start at 0.3 ec as soon as the first set of leaves open and gradually build up to 1.0 ec by around week 3 and up from there. Good luck

cat shit said:

Have a look at coco for cannibas online , I learnt everything about growing with coco there and it's all really good info I use coco for autos sometimes but have been sticking with a peat based medium . That plant needs food have a look and you'll be able to come up with a nutrient regime. In coco I start at 0.3 ec as soon as the first set of leaves open and gradually build up to 1.0 ec by around week 3 and up from there. Good luck

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The auto front right is in coco/ perlite , from sprout I make up a nute solution with 0.4 cal mag and 0.6 coco a and b then I dilute it down to seedling strength around 0.3 0.4 and then you increase your ec up to wherever the plant can handle it this one is 5 weeks and it's feeds are at 1.2 ec. Coccoforcannibas.com

Was your coco buffered?
Does the 250 ppm include tap water or do you use r/o?
How much nitrogen, phosphorous, and potassium do the nutes have? Never heard of a nute line specifically for autos.
Do you ever use plain water?
How often do you feed?
Do you feed to run off?

Delps8 said:

I've heard a lot of myths about autos but nutes specifically for autos is a new one.

It's all the same 16 (or 18 ) chemicals. Some come in pretty bottles, some are in bags but it's all the same 16 (or 18 ) chemicals.

Click to expand...

Hi, thanks for replying
Yes I now see that it does sound funny having specifically Auto nutes but I always thought autos needed half strength nutrients and I'm terrible at math so I looked it up and sure enough found some lol.

MickFoster said:

Was your coco buffered?
Does the 250 ppm include tap water or do you use r/o?
How much nitrogen, phosphorous, and potassium do the nutes have? Never heard of a nute line specifically for autos.
Do you ever use plain water?
How often do you feed?
Do you feed to run off?

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Hi, thankyou for replying.
By buffered do you mean nutes added to it before I put the plant in? If so then no but it says on the package that it's ec & pH buffered. It's called Ugro pure max air. 250 PPM including tap water, because I thought autos only need half strength nutes, is that incorrect? So I got autoflower nutes so I don't have to do the maths of halfing my usual nutes. I thought because it had stretched and id transplanted to go easy on the nutes at first but 250ppm is with the new nutes and added calmag at the dose it says to use. Never use plain water only nute water to run off every day. I upped the nutes and the lighter green has darkened but the edges of the new growth has gone purple in colour and the older growth has purple dots in it. What could that be? I checked and it's not the strain itself I don't think. I checked for bugs but none that I can find. I've done a few grows of photos and never had this purple colour. Do you know by any chance what it could be? I added pics of the nutes and of the purple tinge on the plant. Thanks again

bignugs68 said:

This really sucks to figure bc new growth is often lighter green anyways, but I noticed it's more your 2nd and 3rd node that are most affected. Just looking at this chart..sulphur deficiency looks the closest match.

Honestly shocked your having issues with it so young. I do t even feed nutes till the 3rd node bc I've been taught/read that a seed has enough nutes/energy to make it to 3rd node with just water.

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Thanks for your reply. I know right, that's what I was thinking. The cotyledons are still nice and fat so it's not depleting it's food source. It did stretch quite a bit as a young seedling because I got a new light and thought it was stronger that it actually is but that's fixed. Not sure what this is because the leaves have now got a purple tinge, the new growth is purple around the edges and older growth purple dots?

cat shit said:

Have a look at coco for cannibas online , I learnt everything about growing with coco there and it's all really good info I use coco for autos sometimes but have been sticking with a peat based medium . That plant needs food have a look and you'll be able to come up with a nutrient regime. In coco I start at 0.3 ec as soon as the first set of leaves open and gradually build up to 1.0 ec by around week 3 and up from there. Good luck

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Thankyou for your advice. I'm going to go to coco for cannabis now and have a look. Going to up the feed to 0.8 and see how she fares then to 1.0 if all goes well. I'll keep it mind that you can feed 0.3 as soon as the first set of true leaves appear. Thanks again

BibbyMcBuds said:

Thankyou for your advice. I'm going to go to coco for cannabis now and have a look. Going to up the feed to 0.8 and see how she fares then to 1.0 if all goes well. I'll keep it mind that you can feed 0.3 as soon as the first set of true leaves appear. Thanks again

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No worries happy to help out another aussie!

BibbyMcBuds said:

By buffered do you mean nutes added to it before I put the plant in?

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Buffered coco is pre-charged with calcium and magnesium.

BibbyMcBuds said:

I thought autos only need half strength nutes, is that incorrect?

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Autos are just like any other cannabis plant.......a special nutrient with fancy labels is usually just snake oil.
I'm unfamiliar with those nutes, but veg nutes generally have a lot more nitrogen in them.
I suggest you up your ppm's to around 500 and feed with a pH around 6.0.
What is the ppm's of your run off?

cat shit said:

No worries happy to help out another aussie!

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Should have known I was talking to a fellow Aussie when I saw the name was "cat shit" lol

MickFoster said:

Buffered coco is pre-charged with calcium and magnesium.

Autos are just like any other cannabis plant.......a special nutrient with fancy labels is usually just snake oil.
I'm unfamiliar with those nutes, but veg nutes generally have a lot more nitrogen in them.
I suggest you up your ppm's to around 500 and feed with a pH around 6.0.
What is the ppm's of your run off?

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Oh I see, I read about it on coco for cannabis site so I can buffer the next lot of coco I grow in. Your 100% right about the fancy label snake oil, these cronk nutrients appear to be exactly that & they certainly aren't cheap either so I got diddled for sure. They are meant to be super concentrate but no. I'll use them up then go back to my usual bio diesel. I've made up some nutes at 500 ppm & when I feed tonight I'll make the pH 6.0 & check the run off ppm, ive been feeding at pH 5.8. I forgot about checking the run off. So if 500 goes in & higher comes out that's good but if lower comes out it's not getting enough still? Also incase you see someone else with the purple plant issue I spent a couple of hours googling & the conclusion is that the purple hue on the leaves is usually due to phosphorous deficiency if the temp & waterings are all good & the plant isn't in flower, can be a blue colour too apparently. Thankyou for taking time to help me out, much appreciated