Brown or copper colored spots on leaves

I am in the fourth week of grow auto flower Red Poison I have developed some brown spots on leaves seems to be all over plants top to bottom . I had a fungus gnat problem a couple weeks ago treated with Neem oil and Diatomaccous earth. Seemed to get them under control. As you can see I excavated the root of one plant and they appear healthy to me. I also examined them under a magnifying glass and can not find any fungus gnat larvae. The PH in the soil has always run 7.0 or slightly above. Most recently I switched to flower nutrients. NPK of 2-8-4 Tiger bloom. However i did notice one spot before this Tiger bloom contains both zinc and Magnesium also boron.

You are gonna want to get your ph down some. I believe 6.5-6.8 is best in soil

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Any suggestions I was thinking of adding vinegar and egg shells in case it is a calcium def

Get you a bottle of calmag. About $15

I think Epsom salt works too

Adding vinegar will bring your pH down but you need to be careful it doesn’t bring it down too much. Everything should be adjusted to 6.5 in soil. To far and calcium and Phosphorus will be locked out. Eggshells aren’t soluble enough to provide the calcium the plant needs. Should be added through your nutes.

I have used egg shells in the past on tomatoe plants with great success

You’re not growing tomato’s but adding should not hurt. Just may not be enough.

Don’t think it’s a calcium / magnesium deficiency!! Just my opinion!!

Your talking about ground egg shells and adding vinegar to them in a cup and letting them react / dissolve with vinegar and then applying correct. Will make calcium available quicker. Dont forget to also add epsom salt (magnesium) with your egg shell (calcium) ratio I’ve heard is around 5:1 Ca:Mg

As far as soil Ph if your growing organically and not using chemical ferts and your critters in your soil is being fed that then feed the plant the Ph will fluctuate up and down based on how wet / dry the soil is and at what depth you check it. Normal for living soil to range from 5.5 up to 7.5 or so. The critters take care of things if you take care of the critters. Just my limited experience to date.
If your using man made chem nutes you kill the critters and the above Ph info doesn’t necessarily apply.

What are you using to measure your soil Ph? I’ve found that the soil can be too wet (right after watering and for a day or so after) or can be too dry (right before watering) where the meter won’t read accurately and if the meter always reads the same even at various depths and moisture content than the meter isn’t working or moisture is too low or too high.

Your spots could be from splashing your feed mix onto leaves? Or if you foliar spray…

Hope this helps and HAGD

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Thanks I use tiger bloom nutes I believe it is a PH problem I put some soil in a quart of balanced water and tested that it was very high above 8 so i am going to go with the vinegar and egg shell I should be OK on the mag,s since tiger bloom covers that. Even if I somehow splashed the leaves the PH will still need to be adjusted

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