Well I thought it was but I can't find much on it. Im using promix HP and I'm going to water till I get runoff tonight and check the ph.
Premier Horticulture recommended 5.9 when asked. I used 5.8-6.0 in veg. And, 6.0-6.2 in flower.
For runoff ph, google for "NCSU Pour-Through Runoff Method." That's the most accurate way to measure runoff ph. If you think about the two factors involved in that, you'll realize why casual runoff isn't an accurate reflection of the fertigated soil's ph.
if you really want to to get into soil ph, spend $70 on a Control Wizard Accurate 8 soil probe. You have to use the whetting cloth each time before use (use 0000 steel wool when that wears out). And, leave it for exactly 10 minutes each time before reading. It's handy to see how the ph changes over time (not
just when saturated).
A lot of this is standard-answer stuff. It's too bad we don't have a wiki or something to condense standard info into.
If it needs to either rise or lower can I do that by either raising or lowering the ph of my feedings? Or is it somthing that has to be flushed out to be corrected?
Yes, I sometimes fed higher ph to raise the ph. You can also sprinkle some fine dolomite lime on the top, rake it in to the soil, and let it water in. But, chasing ph is frought with problems.
I strongly advise you to feed enough volume for 20% runoff. Usually the ph problem (for me) was due to overfeeding, salt buildup. 20% runoff can help prevent that from happening. Monitoring your runoff ppm will help you see that condition arise and allow you to dial in your nute strength and runoff volume.
I don't think "no" runoff is ever a good idea. You should mix more volume.
I ended up switching from soilless to soil (but still predominately Pro-Mix HP). See my sig for details. I think it works better than hydro nutes in soilless.
