Plants in Hydro or Soil have a PH range that they uptake nutrients in.
lockout can happen in a soil grow or a hydro grow.
The reason for checking the PH range of your runoff is to see if you have a lockout same as you would in hydro
the only difference is that you can't adjust it in soil as you can with hydro.
This is why I say hydro is so unforgiving. If your soil is out of range, you can correct it at the next watering.
It also like azi said gives you an idea of what the plant is up taking as far as nutrients.
I'm working on my own massive update I know I left you hanging looking for information. But I've had ALOT going on.
You
SHOULD be adjusting your water just before watering whether you're in soil or not if your using bottled nutes you should especially be adjusting.
This is from a local shop owner of 12+ years. If after you mix up your nutes your PH is in range, then no adjustment is necessary (which is what I found I did in previous grows where I didn't PH). But regardless you should always be adjusting for PH.
I took this from a website I found online
Soil
Water going in should be 6-7 pH
If runoff pH is…
- 6-7 pH – in the right range, no changes needed.
- Less than 6 – provide next watering at pH 7
- More than 7 – provide next watering at pH 6
- Continue this formula with each watering.
This would mean that your current practices have been spot on.
Looking at those runoffs your right where you want to be.
I also looked back over your journal. Your water source that's out the tap?
For me those numbers seem very low in ppm practically as low as my R/O water...
I saw someone say Cal/mag. maybe your water source needs to be supplemented a bit?
I usually don't feed this early as like you said the soil should have enough in it based on the ppm of you r runoff.
But as I forgot with my own grow when using R/O (I am, you're not) and LED you should be supplementing Cal/mag
Again, testing the runoff has given you another tool in figuring out what is going on in the soil.
It seems to be NOTHING with what or how you're doing it. But were missing something to tell the entire picture.