Leaves turning yellow on edges

Does anyone know why my strawberry Kush leaves are turning yellow on the edges?
Is this a nutrient problem?
First time this is happened.
I use distilled water at 6.5 PH
Growing indoors.
Giving Foxfarm nutrients.
Soil is Foxfarm Ovean forest.

How close is your light?
What kind of light is it?

Using a 600 watt Vipaspectra LED light.
28” above canopy.
I have others growing at the same height.
This is the only one having the problem.
The yellow eventually takes over the entire leaf.
Then the edges dry out.
All fed the same amount of nutrients.
I’m confused.

how long has the plant been in that soil? And how old was it when you began to feed it noots?

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It was growing in FFOF for 9 weeks.
Went to 1 gallon at 2-1/2 weeks.
Repotted to 5 gallon at 5 weeks.
Started nutrients at 6-1/2 weeks.
Only the Strawberry Kush is having this.
The others 3 are fine.
They all where on the same schedule.

Looks like potassium deficiency, but…

Is the pH 6.5 your reading after adding nutes, just before pouring into the soil?
Are you adding cal-mag (since you’re using distilled)
Have you been following the fox farms flush schedule?

I adjust the PH after the nutrients are added.
I’ve only fed then 4 or 5 times so far.
Only flush a couple weeks before harvest.
My Foxfarm chart doesn’t show anything different.
I never used cal-mag on them.
Only on tomatoes.
Do you think it would help?
If so how much?
Spray or on soil?

This schedule shows the flushes. It’s imperative with fox farms to do this.

Your issue could be from salt build up, lockout, or absent elements. It looks like potassium deficiency, maybe some magnesium deficiency too. K, calcium and magnesium are intermixed so it can be a combination of things. When you use distilled water it’s stripped of calcium and magnesium. Most people supplement with cal mag to offset this.

Not knowing your runoff ppms, my advice is to do a flush as soon as convenient. This will eliminate lockout. Then a mild feeding and see if the yellowing ceases on new leaves. Get back to us in a week.


@Drinkslinger when flushing with sledgehammer, do you do a normal watering, but with sledgehammer added? Or is it a flush as you would flush the plants pre harvest where you run a whole butt load of water through the medium?

Ex. I am following the fox fans feeding schedule, including the bloom nutes (not at full recommended strengths tho). We just had a tropical storm roll thru and we got somewhere between 4-5ins of rain…right before it rained I was able to get a gallon of water + sledgehammer onto all the pots, and I am wondering if what I did is going to be effective at helping with the removal of salt build up?

Thank you for the advice.
I never knew about flushing during vegetation.
I’ll get some Sledgehammer ASAP.
I have some Cal-Mag.
I assume it’s sprayed as a foliar after flushing.
Thanks again!

That’s why you monitor runoff ppms. When you hit about 300 (plus your input water ppm ) you’re done

It’s been a while since I used it, or any flushing agents. Iirc you add a little to a gallon of water. Let it sit. Then run 3-5 gallons more water through the soil. There are sure to be instructions on the bottle.

One can also flush using properly pH’d water. Usually 3-5x the pot size to bring runoff ppms down to a good level. .

Cal mag can be foliar, but I find it most effective as a soil drench. It’s calcium and magnesium at the proper ratio. You can mix it in with your nutes or just plain water. It will drop pH slightly, so be sure to check before applying. Don’t over do it. Follow the directions.

As mentioned above, it doesn’t have to be sledgehammer. Florakleen, flawless finish, or even lots of water will work.

It’s been a few weeks since I followed your instructions.
Flushed with Sledgehammer and added potassium and Cal Meg. For the first couple weeks it was looking promising with no new yellow leaves.
But the last week or so I’ve noticed a more severe yellowing on some new leaves and burning on the tips.
Not sure if I created a new problem
I’m growing 2 strawberry Kush and feeding both equally. And same lighting.
The other one is doing great.
And the leaves are much greener.
Here are some new pics.
Any ideas?

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Do you have the most recent runoff pH and ppm numbers?

Water in was 6.5.
Runoff was 6.2
Didn’t have a ppm meter.
But it looked pretty clear at the end of the flush.
Is it possible that the extra Potassium and CaImag I added is causing nutrient burn?
I’m just guessing

Totally possible. That’s why I was looking for runoff ppm.

If you’re inputting pH 6.5 and runoff is pH 6.2 the soil is still a little low.

I’m getting very concerned.
It’s gone from bad to worse.
The top leaves are burning on the edges and now I’m getting yellow leaves with dark dots on the middle leaves.
Seems to be getting worse quickly.
Even the flowers are half the size of all the other plants. All the other plants look great.
I’m thinking of doing a flush with Sledgehammer tomorrow and not giving any nutrients for a while.
Any suggestions?
Is this a deficiency problem?
Are there any others on this forum you know that might be able to help me out here?

I would double check ph in and out.

Water in was 6.5.
Runoff was 6.2