First grow, first problem. Orange/Brown spots on top leaves

Hello,

Yesterday my 2 plants in the same 10 gallong DWC tote showed signs of what I thought was nutrient defficiency, and the water level was low, so I mixed nutrients in about 2 gallons of water, and added that in. This morning, I'm waking up to a problem. Please help this is my first grow and It's really going well...would love it if it succeded.

So this is yesterday:



No spots or anything. And today:






The PH level was 6.5, I'm adding ph down to bring it down to 6 now.
The PPM was 490ppm ... I'm keeping it fairly low because the amount of water plants drink. I use foxfarm trio for now, and the recommended levels are 3 times what i put in, but I don't think they account for the temperatures I'm growing these in.

Is it possible those were water spots and light burned?

I didn't thought of that.
It's possible, but very unlikely... I was adding water so it's possible that i sprayed some on the leafs...it does look kinda random. I don't think I did though.

I added quite a bit of cal-mag though. More than I usually do. I didn't measure how much water i put in exactly, so i might have overdone on the cal-mag.

The temperature in the tent was 25c (77f), humidity was around 45, because I was running an aircon over night.

I will monitor the plants (happened on 2 plants, on the other one the spots are white) today and tonight, if it stops good... if not, i guess i should change water.

I would say the spots are from ph fluctuation. I would lower ph to 5.8 and raise ppm to 600.
See if that helps.

could be bugs too. you have a scope to look at the underside of the leaves for mites?

rkymtnman said:

could be bugs too. you have a scope to look at the underside of the leaves for mites?

Click to expand...

Not yet, will get one soon...

HydoDan said:

I would say the spots are from ph fluctuation. I would lower ph to 5.8 and raise ppm to 600.
See if that helps.

Click to expand...

I think you're correct... I lowered it back to 5.8 yesterday, and now it's back to 6.5 and the plants drank a liter of water (or even more) in 24h. The ppm is down to 350 from ~450.
I'm not sure why the PH is going back up like this all the time... I'm gonna add nutes and additional water in now.

It seems few more spots appeared on few other leaves, and plant grew significantly. Few new leaves are cupping upwards.

Those rusty brown spots are typically either potassium or magnesium deficiency. Since you already added too much Cal-mag, it’s likely potassium deficiency which is extremely common. You‘ll need to chop them both down & start over.
Just kidding. Add some K, double up on PPM’s and they should be fine.

> You‘ll need to chop them both down & start over.

My worst nightmare. Good thing it's a joke, at least for now!

I just added some nutrients, and lowered PH from 6.5 to 5.9 ...
It's likely that this whole thing started because I messed up the ph when I added more nutes in few days ago, and I didn't notice.

I'm getting new batch of nutrients delivered tomorrow, and then i will completely replace water.
Until then will just regularly monitor ph to make sure it doesn't go far from 5.9.

There seem to be around 8 leaves that are affected (plant on the right). What should i do with them? Pluck them off? The plant is getting a bit busy maybe some defoliation is in order anyway. It's been exactly 1 month since germination.

What nutrients do you use?

I get those spots & other leaf problems all the time that are to me, really just an early indication that I need to make adjustments. Nice thing about DWC is you can correct most deficiencies overnight if you catch them right away.
I chop leaves like a freak on wheels & still get great yields, so don’t worry about that, but your deficiency is early stage & not in bad shape at all.

blueberrymilkshake said:

What nutrients do you use?

Click to expand...

Foxfarm Trio Base set. Something called "Big bloom" and "Grow big".
I'm switching to another, cheaper product. The former is way too expensive, at least where I live.

Ok, 24 hours later the problem seem to have stopped. The rusty spots are kinda pale in color now, and no new leaves have spots on them.
The plant is considerably bigger too.



I realized my PH meters needed calibrating. I had 2 and both of them showed considerably different values.
I lowered PH to something between 5.8 and 6, I'm not sure exactly because since calibration the values are not stable and it's jumping between 5.8 and 6. Will have to recalibrate again.

Problem seem to be that PH was way too high due to bad readings.

Unless you can spend at least $50 on an Apera ph20 or better, you're better off with pH drops.
Drops are accurate and consistent.
The $15 pH meters are trash.

I'm using Yieryi RS485 7 in 1 thing.

It came with faulty charger. Otherwise it worked good. I payed 65 usd for it.

I’ve been struggling with this exact problem. At first I assumed it was just light burn but after reading everything here, I’m gonna adjust the pH and see if that helps. I had a friend help me transplant them and he said the pH was fine and that it wouldn’t be that big of a change, but I didn’t validate. It looks like I’ll be switching back to using the pH drops. Digital ph meter was something like $12-$17

Thanks for the thread.

RIS said:

I’ve been struggling with this exact problem. At first I assumed it was just light burn but after reading everything here, I’m gonna adjust the pH and see if that helps. I had a friend help me transplant them and he said the pH was fine and that it wouldn’t be that big of a change, but I didn’t validate. It looks like I’ll be switching back to using the pH drops. Digital ph meter was something like $12-$17

Thanks for the thread.

Click to expand...

I agree with the guy above, invest in a good ph meter and calibrate it, or use drops. PH is so important, basically nothing else matters if it's not in the correct range.

I check ph at least 3 times a day. The ph probe is in the tote, i just turn the meter on read the value, turn it off.

rkymtnman said:

could be bugs too. you have a scope to look at the underside of the leaves for mites?

Click to expand...

Not saying he's wrong but bugs would and should start lower not higher

I think it's ph. To many new growers buy a 10 dollar meter. Ph is not an option. And more isn't better with nutrients, usually 3 quarters of recommended dose is all plants want

Best sub 50 ph meter imo. APERA INSTRUMENTS AI209 Value Series PH20 Waterproof pH Tester Kit, ±0.1 pH Accuracy https://www.amazon.com/dp/B01ENFOHN8/ref=cm_sw_r_awdo_1MDMT69MAQCB4DB1ETS2

White.Black said:

I agree with the guy above, invest in a good ph meter and calibrate it, or use drops. PH is so important, basically nothing else matters if it's not in the correct range.

I check ph at least 3 times a day. The ph probe is in the tote, i just turn the meter on read the value, turn it off.

Click to expand...

I had been checking the pH an obnoxious amount of times in a day and was told it wasn’t as important but after seeing how they reacted im 100% sure that’s the issue.

As for the meter, i’m not saying it’s going to remain correct but as of today. I checked the pH via drops and my cheap ass pH reader, they came out in the same range. That being said, I can see how it will need to be calibrated often. As for now I’ll continue using the pH meter and occasionally (every other day) then verify it against the drops.

Thank you very much for the link you provided that will Probably end up being what I get soon. And this might just be marketing but according to the meter in the instructions I have it calibrated to an accuracy of .01. That could also just be complete bs lol