Yellow leaf tips and edges... light burn or something more?

[bighits]

Hello,

I looked today closely at my autoflower and noticed some yellowish tips and edges on the leaves. I looked around and tried to figure what could cause that and I think that my light was too low (45cm or 18 inches vegetative stage) but also if it has to do anything with fertilizer or something else from experienced growers would help a lot. ( I have a 300W LED, 50 LED´s on the light).
If anyone has a similar light setup, please shed some info on how far away should the light be from the plants .
Thank you in advance.

[CaptainWiese91]

How much nutes did you give it ? It’s way too small for given nutes right now.
autos don’t need that much fertilizer. What kind of soil are you using? And how big is the pot?

[bighits]

It is like a grow kit ready to use. I don´t wanna say the name of the brand so it's not advertising.
You get a smaller pot, 7 litter or smth like that, coco soil for it, some auto seeds, and fertilizer called coco forte A and coco forte B. Also, there are instructions on how many drops of that fertilizer per 100ml of water for every week so I don´t think its that issue, maybe the Ph level because in the instructions in the kit it only says to put in a sunny spot and water it with those fertilizers and no mention of the Ph level. But after 2 weeks of being at the window, I decided to put it in my grow tent with also very young plants (not autos).

[CaptainWiese91]

Always check Ph, first thing I learned on the way. Or else the roots can’t absorb the nutrients. I hope it’s only your PH, it’s easy to fix.

[bighits]

Okay, I will start from now on this plant as well. Thank you for the help tho (y)

[CaptainWiese91]

I just PH my water, after I supplied it with all the nutrients. I hope it helps 👍🏻 But I’m never adding full strength to my water with autos. I think it’s too much, but that its only my opinion.

[bighits]

Also, should I use CalMag since I am growing in coco?

[CaptainWiese91]

Yea you should- I even feed them calmag every time I give them normal water and nute water. I’m growing in soil - but I know they like it.
But coco you need to do it👍🏻