Why is my Runoff pH Low?
Low runoff pH usually comes from 3 things. One is microbial growth in the substrate. This growth can come from beneficial bacteria and fungi as well as serious problems like root diseases.
If your plants don’t look healthy, have poor drainage or are over-watered, root diseases could be the problem and proper fixes should be implemented quickly.
The second reason for low pH is your plants are favoring cations over anions. Cations are positively charged elements in your nutrient solution and Calcium and Potassium are the major ones. If your low pH is caused by absorption, increasing Nitrogen (Grow) can help with increasing the pH of the root zone.
The third reason relates to amendments and substrate buffers. Depending on what you’re growing in, different substrates can have a strong influence on the pH of the root zone. Something like peat moss is naturally acidic (4-5 pH).
Amendments like dolomite lime are used to increase the pH of the peat and make it much more root zone friendly. Over time these amendments, like dolomite, will break down and the peat moss will become acidic again. Substrate buffers are very strong and in a situation like this, a re-amendment with something like dolomite lime or oyster flour is usually necessary.
