Help! Is this calcium deficiency??

Brought my girl out to inspect her and suddenly she's got this going on with her leaves. I haven't been able to properly look her over in a minute so I'm not sure when this started but it can't have been developing for more than a few days now. Most of her is still very healthy looking but there are a lot of problem areas.
I'm a first time grower doing things very bare-bones. This is bagseed, havent had these spots at all up til now. Growing in miracle grow brand organic soil, haven't given much at all for nutes other than very watered down all purpose plant food by Expert Gardener (24-8-16). I have a bad feeling the nutes may be where I have screwed up.
Any suggestions welcome! I don't have a ton of money to drop though so especially interested in any DIY solutions.

It looks like it could be a calcium deficiency to me. I always recommend picking up one of these inexpensive soil test kits (or something similar) to keep on hand for situations like these. While it won't tell you if you are low on Ca, it will at least rule out N/P/K and pH issues. A lot of new growers who's plants show signs of Ca and/or Mg deficiencies usually have pH issues that are preventing the plant from properly absorbing those minerals.

TreeFarmerCharlie said:

It looks like it could be a calcium deficiency to me. I always recommend picking up one of these inexpensive soil test kits (or something similar) to keep on hand for situations like these. While it won't tell you if you are low on Ca, it will at least rule out N/P/K and pH issues. A lot of new growers who's plants show signs of Ca and/or Mg deficiencies usually have pH issues that are preventing the plant from properly absorbing those minerals.
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I do have an electronic soil tester that has consistently hovered right under 7 for pH, I'll have to scoot to home Depot for something that could test the rest. I had an issue with nitrogen toxicity very recently, is it possible this is stemming from that? I've read that too much of a nutrient could lock out the plants ability to absorb others. Any idea on how to fix this and get her to bounce back? Im very close to flipping her to flower

HighasFrank said:

I do have an electronic soil tester that has consistently hovered right under 7 for pH, I'll have to scoot to home Depot for something that could test the rest. I had an issue with nitrogen toxicity very recently, is it possible this is stemming from that? I've read that too much of a nutrient could lock out the plants ability to absorb others. Any idea on how to fix this and get her to bounce back? Im very close to flipping her to flower

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If the "electronic soil tester" is one of those inexpensive moisture meters that also measure pH then those are 100% useless for pH measurments. Yes, nutrient lockout could also be the issue, and that was one of the reasons I recommended the soil test. If you have excess nutrient levels, and/or the pH is way off, then you can flush your pots with pH'd water until they get closer to what they need to be at. Just prepare a LOT of water if you need to do this. I had some plants one time that were so out of wack, that I had to flush 5 gallon pots with close to 10 gallons of water before they were back where they needed to be. If you have to flush them to that extent then you will want to give them a lower than usual strength feeding when you are done flushing.

TreeFarmerCharlie said:

If the "electronic soil tester" is one of those inexpensive moisture meters that also measure pH then those are 100% useless for pH measurments. Yes, nutrient lockout could also be the issue, and that was one of the reasons I recommended the soil test. If you have excess nutrient levels, and/or the pH is way off, then you can flush your pots with pH'd water until they get closer to what they need to be at. Just prepare a LOT of water if you need to do this. I had some plants one time that were so out of wack, that I had to flush 5 gallon pots with close to 10 gallons of water before they were back where they needed to be. If you have to flush them to that extent then you will want to give them a lower than usual strength feeding when you are done flushing.

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Ugh, yeah, nail on the head - cheapo tester, though it's for pH and "fertility", not moisture. Either way I'll grab some legit testing strips. I think my landlord changed something about our water filtration recently, so that could very well be why this has suddenly started happening.
Thank you for the help!!