What is the matter with my plants?

[recky]

Hi guys! Just wanting some help, I have two plants in a 150 cm x150cm x200 cm grow tent. I have a 600w led light, they are in a 15litre 70/30 coco perlite medium. My problem is I have yellowing leaves at the top of my plants. coming from the stem out. I also have a brown spot on one of the leaves. The first image is the first plant with the brown spot on it the second ones are the plant i feel is most badly affected by the yellowing streaks.

 

[Jack420]

Have u started to feed nutrients

 

[recky]

Yeah thanks, started after week 1 now week 3. Started feeding them after they started to show Deficiencies. Currently feeding them every other water with fertilizer and nutrients. Fertz has an npk of 14/4/15 and nutes are 28/5/10

 

[Jack420]

Wat brand and wat strength are u feeding them

 

[ZebSoames]

pH?

 

[recky]

using a liquid plant food for nutrient's called growzilla and and my fertilizer is called photrogen. I'm feeding them a quater scoop of a ten millimeter spoon for the nutes and fertz per every in 4.5 gallons of water. Sorry don't have ph reader yet!!. Just using regular tap water, but In wellington, where i live the water is pretty optimal. By the way I feed them about 3 times a week, twice with the fertilizer and once with the nutrients .

 

[MickFoster]

You have several problems. You should have started in smaller containers - one of the reasons your plants look like a week old instead of three. Without a way to read pH - you're dead in the water. Never use plain water in coco. My guess at this point is that it's pH. Also, is your coco pre- buffered or did you pre-charge yourself?
These plants were started in solo cups and are 3 weeks from sprout and fed everyday. Good luck.

 

[Jack420]

Yeap coco is hydro so ph need to b on point

 

[Icemann420]

 

[ZebSoames]

Hempy is the only method of growing that pH isn't such a big deal, except out doors.
Even a spa test kit is better than nothing

 

[Jack420]

Yeah or pool strips or drops really cheap n u can grap everywhere

 

[MickFoster]

I don't own a pH meter. I've been using the GH pH drops for many years. It's never wrong. No need for calibration. No need for 7.01 and 4.01 solutions. No need for cleaning and storage solutions. No need for a meter.

 

[Jack420]

I use the drops also they work great

 

[MickFoster]

The color chart on the bottle is a bit off so I use this for reference.

 

[recky]

I have autoflower's which I should have mentioned hence why I put them in the 15 Liter's. yeah I went out and bought a pool ph strip myself. The reading's after putting some white vinegar in the water was at 5.5 down from 7.2 so will keep it that way now I have a ph reader, just need to get the ec meter sorted out. the run off from every plant after putting the diluted white vinegar were 6.2, 5.8 and 5.5. fed them as well, should I just keep on feeding them every water with ph around 5.8 at a consistent good level?. Sorry didn't see your comment before watering and feeding them!