Low PH on runoff

Long-story short -- think you just need a few extra water-only irrigations of proper pH. you could give it something like 8ph to triy to balance it out. Because there is little time left, baking soda is fine to use - even 3-4 months probably is okay, but not so much for mothers or other long-term potted plants. ------- what was the runoff pH before? That is essential to know how much to react to this. Due to mechanics of how this is measured, it's more art than science. If there was a major ph issue, which at ~4 would likely occur with P, Ca, Mg, S, Mo, and even N and P might have reduced availability, you'd see numerous issues all over the place of varying sorts. I don't see a plethora of symptoms in your plant that reflect this sort of ~4pH level. Runoff is dirty and there are many reasons why the ph reading can be drastically different than what is in the pot. This is why knowing what it is when things are going well is a good baseline to compare to -- the more it deviates, the bigger the change is occurring... this deviation more important than the actual reading Also, make sure to measure the runoff at the same point each time... if you are measuring it in a runoff basin, if that basin is dirty, it's going to affect the reading etc etc.. maybe let water run out for 5 seconds or 10, then dip strip or probe into stream or anything akin to that.. be anal AF about it, lol, because there's already a ton of error invovled. your plants might be slightly overfed - some curling which can be caused by more than just N-tox. The leaves would be very dark and shiny, if it is a nitrogen-related issue. You look faily close to the end, so i wouldn't do anything too crazy. Give it some water-only irrigations with a little runoff each time. water habits for soil -- always water entire volume of substrate. Do not try to give it a volum of water you choose. That amount of water is determined by pot size, how the soil is constituted and how long you wait between irrigations. A little runoff is good to ensure this, but runoff in soil wastes amendments in the soil. You increase runoff if you think there is a buildup occuring. take note of how it happened, and adjust your frequency/concentration of fertilizer and possibly how many water-only irrigations between fertilization. wait for top 1" to dry, and water entirety. it's that easy. can't fuck it up "overwatering." Adjusting your frequency/concnetration of fertilization after you run into buildups will avoid buildups in future. trial and error until it's smooth from seed to harvest.