Strange leaf spots + Nitogen Toxicity?

[Olderfart]

Thanks. I have been keeping pots of water in the tent, as well as hanging a wet towel, and it hasn't seemed to be doing much. Your suggestion of having a towel half submerged in some water sounds like it might be more effective. I'll try that. Cheers!

It’s my preferred tool. Best if you blow on the towel with a fan.

 

[Cannanoob]

I have a 4x4 and a 8x4 tent. My watering usually brings my humidity up. And the dehumidifier brings it down if it is too high. Do you have an extraction fan or intake fan? If so that cud be causing your humidity to be lower. If space is an issue hang a wet towel off a top bar in your tent like others suggested. Save money on a dehumidifier if it works.

Yeah, I do have an extraction fan. It's attached to a carbon filter which does a perfect job of eliminating odours, but it seems that this is what is causing my humidity issue. Thanks to all of the suggestions on this thread I have been able to raise it to 45% using towels, etc. but I will definitely invest in a humidifier soon, and possibly a dehumidifier for the summer as well. Thanks

 

[Cannanoob]

Ok, so I may have found the source of the nutrient imbalance!

I bought a soil PH tester and it is reading at around 7.8 - 7.9!
I always check the PH of the water (after adding the nutrients), and I usually have to + it a bit to get to it ~6.5, but now I can see that this has no bearing on the soil PH, which I've just discovered is much higher...

I'm kicking myself for not checking this sooner, but at least I know now.

So, does anyone have advice on how I should go about lowering the PH of the substrate?

 

[Cannanoob]

It’s my preferred tool. Best if you blow on the towel with a fan.

Thanks, that did the trick! Having a fan blowing directly on the wet towel has made a big difference. The humidity has increased by 10%. Cheers

 

[Proph]

Ok, so I may have found the source of the nutrient imbalance!

I bought a soil PH tester and it is reading at around 7.8 - 7.9!
I always check the PH of the water (after adding the nutrients), and I usually have to + it a bit to get to it ~6.5, but now I can see that this has no bearing on the soil PH, which I've just discovered is much higher...

I'm kicking myself for not checking this sooner, but at least I know now.

So, does anyone have advice on how I should go about lowering the PH of the substrate?

I seriously doubt that your soil ph is close to 8.. What type of soil probe did you get and how did you check it?

 

[Cannanoob]

I seriously doubt that your soil ph is close to 8.. What type of soil probe did you get and how did you check it?

Its this:

and I have left it in the soil for a while, with the probes around 5-6cm deep into the soil.
It has given almost the same reading for two different pots that have the same substrate, same nutrients, etc.

Why do you say you seriously doubt?

 

[Cannanoob]

Its this:
View attachment 1281275

Its this:
View attachment 1281275

and it has given almost the same reading for two different pots that have the same substrate

And I have been checking the Plagron site too, and have seen that they recommend checking the soil PH regularly when using their Light Mix, which I haven't been doing until now.

 

[Proph]

Its this:
View attachment 1281275

and it has given almost the same reading for two different pots that have the same substrate

Those things are questionable at best.. Plagron lite has a few ph buffering sources.. It's really hard to get the soil ph out of range. A true soil ph probe costs about 100 us dollars. I use a Kelway..

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I would find a few more test subjects.. Maybe outdoors somewhere, or old soil if you have some around. Something to make sure you're getting readings other than 7.8-80..

 

[Proph]

And I have been checking the Plagron site too, and have seen that they recommend checking the soil PH regularly when using their Light Mix, which I haven't been doing until now.

That's because it's a compost and buffered to stay between 5.9-7.0. If anything it would be lower than 7, not higher..

 

[low_and_slow]

Plagron light mix is not soil. It is a pH buffered peat product with added perlite.

You should be treating this as a semi-soilless grow and using hydroponic pH ranges.

6.5 is too high, target 5.5-6.1 as your ideal pH range.

Soil probes should not be used in hobbyist growing, pH drops or a calibrated meter will give far more valuable information about acidity.