Brown spots: nute burn, wrong pH, or something else entirely?

[Yogso]

Hello everyone.

I have these brown spots on my leaves, and no idea what it is. Hopefully you can help me.

Problem: -Brown spots on leaves. Still very small but I wouldn't want it to increase since my plant is young.
-begining of yellowing on one leaf
-First true leaf all droopy and yellow spot.

Medium/grow method: Soil, biobizz light mix

Feed and supplements used: Alc a mic 1.5ml/L. Fed twice the biobizz Bio-Grow at 0.75ml/L so far. Did some foliar feed with water + alg a mic yesterday.

water source: "Cristaline" bottled wated, pH 7.7.

Strain/age: DP's AutoBlackberry Kush, day 15 today.

light used: Mars hydro 300w (135w) at 22inches (recommended 18 to 30 inches)

Climate: 50% humidity, 20-22°C

Additional info: I followed Biobizz advices, they said you don't need to check pH when using their soil and nutes. They also said to start at 1ml/l of grow, and to feed everytime.

I actually just checked the pH of what I fed them this night, and it is the exact same as my water: 7.7.

My best guesses would be nute burn (since I fed them twice already), or wrong pH (despite what Biobizz says), or maybe light burn from the foliar feed? But It wasnt the first time I did it, and they enjoy it like crazy usually (praying hands whenever I do it).

Also, the second plant is fine, and growing strong (although her first true leaves are also a bit droopy).

edit: it might actually be wind burn. Since the stem is weak, my fan was mainly blowing toward her to thicken it. i've moved it much futher away now. however, it does not explain why the first true leaf is dying. Any advice appreciated!

Edit2: decided to cut the sick part of the first true leaf. It really looked Bad, like it was being eaten... See the last pic.

 

[AppleFritter]

That looks like a spider mite or something in the third photo. I think there is a sticky about how to get rid of them

 

[mohawk warrior]

whats the soils ph?

I'm gonna say its too wet... possible to hot... that first pic looks like it, too much in the foliar like you said
..
just smoke a joint and let this play out a bit... thats what i'd do...
spider mites? he's trying to scare you.. that's wayyyy noticeable .. and a nightmare.

best thing to do is go...
hehehehe he's gonna kill me...

hey @Waira
does that look like mites to you?
wait...
@Eekman gonna pick on you for a bit... give waira a break
wanna help this dude?

 

[Yogso]

whats the soils ph?

I'm gonna say its too wet... possible to hot... that first pic looks like it, too much in the foliar like you said
..
just smoke a joint and let this play out a bit... thats what i'd do...

I'm gonna wait a bit then! I wish I could ease the wait with a joint, but i'm on a break right now... One more week i'll try to cool the place down in the meantime, the new air extractor i'm acquiring on saturday should help.

I don't know the soil pH, i still can't water to runoff.

 

[mohawk warrior]

I'm gonna wait a bit then! I wish I could ease the wait with a joint, but i'm on a break right now... One more week i'll try to cool the place down in the meantime, the new air extractor i'm acquiring on saturday should help.

I don't know the soil pH, i still can't water to runoff.

by "too hot" I mean the soil ... to active.. too much juice..
personally, I'd let it dry out and water with plain water for next time maybe two; depending on what you see before the next watering will decide weather or not you should give it a good flush or not..
ideally you'd not wanna have to.. it'd be better to be able to just give it regular waterings but that may not be a choice..
more food doesn't always mean bigger plants. same goes with water.. most people water any plant way too much..

u have full plant pics? and a soil probe is not a bad investment... as waira says..
amazon.. I forget the brand... like 20 bucks or so.. keep ph between 6 and 7 and your golden

 

[Yogso]

I'll take some more pics tomorrow. Next watering will probably be plain water, just in case.

I'll think about buying a probe. It was supposed to be a budget grow and it's already 100+ € over the base budget so...

 

[Aunty Edna]

It was supposed to be a budget grow and it's already 100+ € over the base budget so...

You are not alone...

 

[Arthur]

Doesn't look like mites to me either, the tip that's yellowed looks like exactly like what mohawk warrior said... a little nute burn. No worries, pH your water and no feed for a couple waterings then feed @ a reduced amount. You should be golden.

 

[Yogso]

Quick update guys. She's looking much better today. The spots aren't disappearing but they aren't growing any bigger. I'll stick to the advices, next watering water only, and i'll pH the water no matter what biobizz says. Thank you all.