m0useanswered grow question 3 years ago I would aim to have that PH aorund 6.5-6.8 if that is indeed soil. need dirt to be soil.
If it is soiless 5.8-6.2 works best for flower. The lower 5.5 is good in veg. anything mainly composed of coir or peat.
With autos as well they will not be as heavy of a feeder as their photoperiod counterparts.
I would suggest monitoring your EC/PPM of the feeding solution your putting into the soil.
BioBizz nutrients tend to tend downward into the lower PH after sitting for a bit.
If you not letting it sit for 24hrs before watering you may want o try that before ph adjusting.
this is a good feeding reference for auto's, still have to watch your plants, if they are asking for more, give them more.
https://www.autoflower.net/forums/threads/med-man-method-feeding-chart-ppm-ec.47856/
Best Of Luck and Happy Growing!