Help diagnosing yellow/brown leaves

Hello everyone! I’m hoping you guys can give me some tips about what could be wrong with my plant. It looked great a couple weeks ago. I got a bit sick and didn’t pay much attention to it for a while and now the leaves are turning yellow/brown. I did go a bit too long without watering it a couple of times.

Indoor Grow
Mango Kush feminized photo from ILGM
Tap water – PH 7 and PPM 40 before adding anything
PH 6.5-6.6 and PPM 1000 after adding nutes and PH up
PH runoff is 6.2- It was a bit lower (5.8) but I’ve been working on raising it
Soil – Mostly peat moss and worm castings
Using Advanced Nutrients
2 plants in a 4X4X6 tent - Each in 5 gal fabric pots
Mars Hydro SP3000 and VIPARSPECTRA P2000 – 500 W total
Day temps 78-80. Night temps 75
Day RH 45, Night RH gets up to 65 (working on lowering)
Air duct in is attached to a window AC during the day to keep temps down
4’’ exhaust fan with carbon filter out and 4’’ fan to bring air in
This is my 3rd grow so I’m pretty new


Welcome to the community @jcun05

Looks like a nitrogen deficiency.

Or potassium

What nutes are you giving them now? Not brand.
How long in flower now?

Do you water to runoff?


Normal fade of fan leaves during flower. At this point in your grow I would recommend removing all fan leaves anyway. Plant will continue to slowly lose leaves as flower matures.


I flipped to flower on May 3rd. I water until I get a bit of runoff. Probably 10-15%. I’ve been giving AN grow, micro, bloom, bud candy, big bud, nirvana and sensizym.

1 Like

@jcun05 How long have you been using the boosters?

Although I am not familiar with AN. As in I haven’t used them… Boosters in general can cause nute lockout. I stopped using them but when I did… I found I had to stretch out my initial booster usage… Instead of starting at for example… 1/4tsp…I would start at 1/16tsp…then to 1/8…so on… A week at a time… To slowly bring the initial boosters up to acclimate the plants to it.

I mire often than not got nute lockout… And chased it the rest of the grow if I wasn’t careful.

You may want to flush… If you had recently started the boosters.

Then as soon as it dries out start you regular nutes for the week if flower as you normally would.

As @Myfriendis410 said… Leaves do start dropping in flower… But I suspect thus may not be it.

I agree with myfriendis410, definitely could be fade.

Another question I have is are you using cal/mag on top of your nutrients?

Cal toxicity will cause lockout of potassium and magnesium starting at the middle of the plant like your are experiencing, just food for thought.

I’ve used cal-mag a couple of times at half strength. Could have been too much with the other nutrients. I assume a flush would help if this was the case?

I’ve been using boosters pretty much since a week or so after flipping to flower. So I’ve used them for about a month. I used them every other time I watered. I used a half dose the first time and then went to the full recommended amount. I probably should have started out a little slower. I didn’t get a chance to do a really good flush today but I did water them with only PHed water. PPM runoff reading was around 800 with only water going in.