Ph problems

My run off is measuring 4.5-5.0.I’m using black gold all purpose I think it’s been acidic out of bag.I retested some fresh out of bag its run off was also 5.0 using water with ph of 7.0.My seed mix run off stays at 7.0.
What can I add to water to slowly bring up ph during flowering?What about ashes from cured red oak?
I’m getting sporatic growth.It seems right before I water.I’m not sure if it’s because ph drops when soil is drier??The old growth is dark green while new growth looks great.

I added ag lime to the mix in storage bin.It’s same soil.Will ag lime raise the ph of the soil in my storage bin?Does ag lime just neutralize acidic soil or does it keep raising ph levels if too much is used?

Yes it will be a PH up. Neutralizing acid is raising the PH. If your PH is 4.5 and it is raised to 7.0, it is now neutral or you could say has been neutralized. And yes, excessive amounts will raise PH levels too much. Soil buffers the PH a lot and therefore has a pretty broad range of acceptable ranges, soil can be fine at 6.0 to 7.5 for cannabis in most instances. With the ideal target being about 6.2 - 6.3 PH for very amended organic matter composted soil. A lot of coarse perlite can be a PH stabilizer in a acidic composted soil and won’t turn the soil overly alkali like a garden lime could.

Does using coarse perlite add loamyness to soil?Does adding loamyness help stabilize ph?
I have no idea what is causing the growth spurts.It seems to happen right before watering or adding nutes,but if everyday had growth spurts my plants would be much bigger.

Coarse perlite adds drainage and aeration but is mostly silicon and the acid will interact with it and raise the PH slightly and slowly but this is only for mixing in the soil, well amended into it, not something you can add to the top of soil in a soil that is already inhabited by a live plant, like you can garden lime. Are you sure you are not over watering? The growth spurts may be most significant when there is lots of oxygen available at the roots when the soil is a bit dryer.

I may be over watering.I usually water when containers get light in weight,then water slowly until there is a run off and remove all water in run off dish.
My containers only have holes drilled in bottom so all the excess water may not be escaping.I’ll drill a few holes in sides and see if that might help more water escape after watering.
I may have to get a soil moisture meter.

Also you really need to get your ph above 6.0 ASAP.

Add dolomitci lime to your Black cow.

Any idea how much to add to 3 gallons of soil.The bag says 4-5lbs per 100sq feet.

I disolved a tablespoon in a 1/2 gallon of water and used it for watering in one container.In another I sprinkled it on top soil and watered it in.
I can’t get my head around why my soil meter reads 6.5 but my run off is definitely acidic.The nute I’m using is more alkaline than acidic in pure form.
How long until lime starts to buffer soil?I thought about using water with a ph of 7.5 and see if that may help while soil starts to return to normal.
i also thought about using oak ashes.I read that wood ash has all nutes except nitrogen so it might help plants in bloom?

Approximately the top third of the soil is going to read very different than where most of the roots are. Again, how are you taking the different readings? You never clarified that. If you are mixing a small amount of soil from the top with some purified/distilled water and then reading it, that will not be an accurate reading of what is going on in your root zone and that is where it counts, if you have a metal soil probe you can probably stick it in deep enough that you will get to where most of the roots and their ion exchange is going on and get a more accurate and more similar reading to your run off.

Thanks for the help.
Yes it’s definitely more acidic down by the roots if I bury the meter all the way.It reads 5.5.The wash off a very low 5.0 maybe 4.8.
I lightly limed the top washed it in the soil with water.
I have no idea how long it takes lime to react with soil.The lime has 21% water soluable calcium in it.Hopefully by next watering I might see an increase in ph.

So it sounds like you do have a metal probe, that was what I wasn’t quite sure about. Two other thoughts, some pots have pretty big holes at the bottom, kinda on the side, you could try poking your meter in that area as well and see what kind of reading you get, and don’t forget sometimes you need to kinda buff the metal parts with something like a rough paper towel to make the metal probes tips kinda shiny, less build up on the metal and you’ll get a better reading.

Dissolving it well in the water instead of sprinkling on the surface might be the better way to get your soil to absorb it more evenly.

Yes,a metal probe.
That’s a good idea.My containers didn’t have holes in the sides but a drill fixed that.
So far I think the ph is rising.Next watering will tell more.
I get much better drainage now.

That is the whole point of adding the dolomitic lime. it buffers the soil PH. Sounds to me like all is great. you don’t dissolve the lime; you add it to your soil. Water, and it does the job. 2 TBS per 3 gallons/ 13 liters, of SOIL.

If your soil probe reads 6.5. Forget about the rest. Soil runoff is best used when you do not have a meter. Also; It is a great idea to use ph 7-7.5 water. The lime will buffer it and your runoff will raise.

Relax. It sounds like you will be just fine :mrgreen:

p.s. Changes do not happen overnight when growing plants. Relacx, and be patient; Watch the plant more than the meter! Learn to grow the plants. They will teach you what they need. Peace