Requesting Diagnosis

ILGM Community,

Thanks for your time in reading my post. I created a different post asking for general advice about a week ago, I felt I needed to have a completely separate post now because I feel like I have something wrong with my plant that I need to address.

My concerns:

Today is day 28 of my grow

I was told some yellowing is normal on the oldest fan leaves but it seems to be more prevalent, even on newer growth. The yellowing is very weird, splotchy.

The leaf tips are curling inwards.

I’ve included four photos. Three of my concern, and the final photo is the overall plant showing some LST I’m using with some wire.

Very basic indoor grow. Using FoxFarm Ocean Forest Soil. When the soil is moist I use my PH meter and get ph 7 throughout. The meter doesn’t work well in straight water but I’ve gotten it to read my runoff at 6.8.

I was doing 24hr light schedule but I reduced it to 18 on 6 off due to previous recommendations.

Maybe it’s because I’ve been following the fox farm nutrient feeding schedule and giving it nutrients it doesn’t need? Been using FoxFarms Grow Big / Big Bloom.

My temp is 75F, and my humidity is quite low but there’s not much that I can do about that due to costs.

I’m using a cardboard box lined with reflective material and a Mars Hydro TS600 (100 watts) 18” in from the top of the canopy.

Any advice on what’s causing this yellowing? Too much nutrients? Not enough? I water it every 2-3 days.


When watering with nutrients, can you remember if you got the lower leaves wet at all? Doing that can cause the nutrients in he water to burn the leaves. I’m not the most experienced grower, but from what I see it either looks like that or pH fluctuation, but you said you keep yours relatively solid. IHGM has a diagnostics checked that you can look at to try and determine what’s effecting your weed plant if you don’t get any good answers here.


At a quick glance I’d say you’re feeding too much, started feeding too early, and your ph is a little high.

Do you also have a tds/ppm tester? If not, you should. Relatively inexpensive one will do. You want to be able to test concentration of your nutrients applied and runoff. I’m guessing your runoff will be high. The ff soil you’re using should have fed plant alone up to this point. If you’ve been giving nutrients you may have potentially toxic levels of nutrients in your soil. In addition to info you’ve provided the the dark green color and clawing leaves also indicate this.


What is the ppm of the FF nutrition solution you been giving it?
And how often?

I second that. Looks really dark green to me which indicates too much N. Makes sense because veg nutes have a lot of N.


You just now in week 4 your soil should carry you thru week 4 and 5 then start watering to runoff then checking with tds pen ppms if below 1000 start feeding. Start feeding on ff feeding schedule start on week 4 and first week use about 1/4 of strength of what cause for and always water to run off or you will get salt build ups and get lock out.

Also only need first 4 nutes on list

Is the term “clawing” because the edge of the leaves develop bigger serrations?

Not what i was referring to. The tips of leaves bent over sharply, looks like a raptor claw.

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Yes! This is the exact thing I was following, except I’ve been using a 1.5 liter water bottle with holes poked in the cap so it doesn’t dump fast. (cutting the dosage in a 3rd since it’s about a 3rd of a gallon)

The directions there say in the seeding stage 6tsp, week 1 6tsp, week two then you introduce the second nute.

These are the three nutrients I bought:
Big Bloom
Grow Big
Tiger Bloom

I just got a Vivosun PH & TDS/PPM Meter. Keep in mind I did a big watering two days ago based on the advice I might have used too much feed.

I watered again to get a good amount of runoff. I think I got like 4.83-5.12. I’m like dang…

My PPM was 1,200.

So weird because when I use a ph rod type soil tester that says 7.

These are useless. :grin:

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You i am with @HMGRWN you need to throw that ph soil tester away and check your ph in and ph out. When mixing the nutes you need to ph water after mixing and check your run off ph.

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Agreed, dont try and test soil ph, test the nutrient solution ph and balance it. Them soil prop things are a gimmick, they don’t work

I wanted to reply to you since it says you’re a regular. Wondering what your thoughts are on “how it’s going/growing” today is day 35, it’s exploded in height!

I did like two flushes after testing my runoff PPM because it was like 1,200 and I got it down. I’ve also been testing my water/nutrient solution PPM and I’ve been making sure it’s around 900ppm.

The only thing I noticed now that I bought the vivosun PH tester is that my water PH out of the tap is like 7.5, and when I make my nutrient solution it’s like 5.4. Should I be adding a ph up to make sure the nutrients and water clocks in around 6.5-7?

First off, she looks great! :star_struck:
Congrats on getting to flower stage!

Exciting times! That would be the preflower stretch. She may seem to “stall” soon but it will steadily add length and density to your forming buds.

The flush may not have been necessary but probably didn’t hurt anything either. 1200 is not a bad level to be at. Over 2000 may indicate salt build-up. :wink:

Yes, for soil, Ph going in should be around 6.5 to 6.8. :+1:

Since I have an aquarium, could I use this to increase the ph of my nutrient solution? Yo, I really appreciate your broken down replies you’re super awesome. Last question is, how often should I be watering my plant? And how much water should I be pouring into the container (it’s 5 gal pot)

Safe for fish is safe for plants. :white_check_mark:

Cannabis likes to dry out between watering/feeding. What I do is lift the planter and feel the weight. You can tell when it is lighter, it is dry.
Some people wait to see how long it takes for the plant to “droop” then water one day sooner next time.

I mostly use 3 gal planters and 1 gallon of water/solution usually gives me about 1 quart of runoff. General rule of thumb is 20% runoff every time you water/feed. This prevents salt build up and testing it for the PPMs gives you an idea of available nutrients. I would guess around 1+1/2 or 2 gal every 3 to 5 days depending on your soil mixture.
Most good soils will feed for around 5 weeks with only water. When your runoff PPM drops below about 1000, it is time to start adding nutrients.

You are getting well into flower now and it is time for increased amounts of potassium and phosphorous ( The P&K part of NPK as seen on fertilizers) and reducing nitrogen.

The issue I’m having is:

I get ph 7.5 water 35ppm from the tap.

Then I add a tiny amount of Tiger Bloom.
I shake it up and test ppm, I get like 800. I test the ph, now it’s 5.4.

So I add “Alkaline Buffer” in small increments until ph is 6.5. Then I test ppm and it’s crazy high 2,300.

It’s like impossible to get ph 6.5 and ppm 1000 or less.

I keep diluting and retesting and just said F it, and poured in 800ppm and 5.4ph water. I feel like I did something bad because it looks like a lot of the leaf tips are yellow now. Ugh…

Here’s a pic. I feel like I should just be using water only and say screw it, it comes out how it comes out.

So, I used a tiny amount of tiger bloom. Ph tanked, I used baking soda to get the ph to be 6.5, and the ppm read out 800. It just looks like I’m killing it. Maybe because of using ph balancing and nutes when I should just be using plain water?