I think I'm having PH problems but I'm having difficulty understanding what the proper PH should be. I've read different things. Could a grower who uses Promix HP tell me what they do? To get the soil's pH, I understand I should water with water that has been adjusted to a 7.0 pH. So if I water with 7.0 and the run-off is 6.5, does this mean the soil(less) pH is 6.75? Or is it 6.5? I'm confused So yeah, if someone could tell me how I calculate the soil pH and what the runoff should be with 7.0pH water for pro-mix I'd appreciate, I'm developing mushy brownish spots on my leaves (it's not crispy at all). This is happening to pretty much all the clones I transplanted about 2-3 weeks ago, but it only started in the last few days, They are still in veg. I am guessing it has something to do with pH and phosphorus. I will measure the run off tomorrow, but I need to know how to do it first and what I am aiming for. Last question, what should be the pH of nutrients going IN to the plants if using pro-mix. 6.0-6.5? Or does it depend on the acidity of the soil (i,e, make nute solution more alkaline if the soil is found to be too acidic?) Thanks.
Ph is a fun little bitch to play with 7.0 water is too much for a plant, you want between 5.6 and 6.8 ph (I may be off on my numbers, I'll post a pic) measure the Ph in, and measure the Ph out. Now, you do not want to start 'chasing the ph' this just gets frustrating. If you get 6.5 from 7, I would try to water with a Ph of 6. That would give the plant everything they need.
If you are using organics then you don't need to worry about pH. You need to worry about your microbes, as they will regulate and buffer the pH in the media all on their own. If you are using chemical hydroponic fertilizers then you want to balance your solution to around 5.8pH. The runoff is not a conclusive way to find the pH of your media as some elements are retained and some are rinsed. This changes the solution. Peat tends to become acidic as it breaks down. It is important to be aware of the media pH when using it. An extraction slurry test is probably the best method available to you sans a soil probe. Using a small scoop take a few tablespoons of media from as deep as you can in the peat without damaging the roots (badly). Mix this with distilled/deionized water at about a 1:1 ratio and test the pH of the muddy slurry with your pH pen. Ideally it should be somewhere around 5.8pH.
When someone says "my soil ph is 6", for example, are they simply referring to the run-off following a watering with PH 7 water or would you say you soil pH was 6 if the run-off was 5. Even if I shouldn't normally water with PH 7, aren't I supposed to use neutral water when trying to figure out the soil ph? My understanding is that you use neutral water. The actual soil ph is somewhere between 7 and the run-off you measured. Is this not correct? I really need to get a handle on the fundamentals because I am not clear on this point and it's obviously very important to understanding pH.