First time grow, suspected spider mites, looking for second opinion and solutions

[Vibesgirl]

Problem: leaves started getting yellow/rust colored splotches on top leaves day 52, flowering stage, assumed a fungus, brought a leaf and pics to local grow store, they said spider mites, sold me SNS 217 all natural spider mite spray, not seeing any improvement, no webs evident

Medium/grow method: soul/

Feed: and supplements used: Gen Organics, Bio thrive and Bio Bloom, light feedings, stopped feeding 2 weeks ago

water source: in beginning, tap water PH balanced, then switched to rain water, gathered in barrel, PH neutral when tested

Strain/age: white lighting and massive cracking autos

light used: optic 6 COB

Climate: temp range 75-80, r approx 50

Additional info: looking for a second opinion, and will any of this be smokable?

 

[GoAuto6]

Is there spider webs all over? How's your pH? A soil probe is needed to check in pot pH.

 

[namvet25]

Check real close under the leaves for bugs and if you don't find any then you have another problem.Let us no what you find.

 

[Vibesgirl]

No webs, don't see bugs under leaves, I read that you can hold a piece of paper under and shake the leaves and you should see some on the paper, I did that and nothing!
I was reading on the deficiency thread and now I'm suspecting a phosphorus deficiency, especially with the timing at flowering. I need to go out and buy a soil probe, but I have read that their accuracy is questionable.
this issue is with plants in my tent, I have 4 outside on a deck in containers and none have this issue, they are doing great.

 

[GoAuto6]

I use the accurate 8. There a little pricey but the best tool in my grow room, well worth it.

Check out eBay

 

[Vibesgirl]

Thanks, but if my water is ph neutral wouldn't my soil be fine?

 

[GoAuto6]

Thanks, but if my water is ph neutral wouldn't my soil be fine?

No, as you add nutrients to the mix the pH can fluctuate. Usually it causes it to rise.
Let's say your water is a pH of 6.5 nutrients will cause it to go up to say 6.8 now as you keep going pH in pot will rise above as it is stored in the medium. If that makes sense.

 

[Vibesgirl]

Gotcha, h2o tests 6.2-6.4, took a soil sample plug at root zone and tested with rapidtest, that was 7. I'll get a probe soon.
Could not having fed them any nutes for the last few weeks been an issue? When we first saw flowers, start GO Bio Bloom and saw burn on the tips of leaves so we stopped after a few light feedings. I have 4 plants outside, same grow bags, soil, water, except for natural rain, only difference is sunlight vs led and natural air. They show no symptoms of anything on their leaves.
used a magnifying glass again last night and still no signs of bugs, eggs, webs, etc.

 

[GoAuto6]

I think it's more of a lock out issue, if your getting 7 on the rapid test I bet your more around 7.5 maybe closer to 8. I be got a chart some where, illI look for it.

 

[GoAuto6]