Indoor The start of a new mi5 grow.

[Justinsane]

Hiya.

Tomorrow i´m gonna start 12 new mi5 and i have one little question about ph.

Im gonna start them in used soil, and i tested the ph of the soil.

Ph in was 7.3 and run off was 5.9. Should i correct this in anyway or are the numbers good to go?

Love Justin

 

[Villain]

Good question, my tap water is 7, when I add nutes it goes down to 6, then I bring this up to 6.5, my run off is 5.3, i'm waiting for the postman to deliver a soil test kit and see if the 2 match

Is run off water a definite way of testing soil PH?

 

[JM]

It's a definite way of determining if you're anywhere near where you need to be... and you re NOT currently...

https://www.autoflower.org/f42/ph-potential-hydrogen-manual-11586.html

correct to 6.3 - 6.5 and then proceed as normal...

in 6.5 out 5.3 suggests soil ph around 4.9 ish.... this is a dire corrective emergency!

see charts in above link!

 

[Villain]

It's a definite way of determining if you're anywhere near where you need to be... and you re NOT currently...

https://www.autoflower.org/f42/ph-potential-hydrogen-manual-11586.html

correct to 6.3 - 6.5 and then proceed as normal...

in 6.5 out 5.3 suggests soil ph around 4.9 ish.... this is a dire corrective emergency!

see charts in above link!

The run off does surprise me as the soil i'm using is pretty much marketed in the UK for cannabis growing, i've searched the net for raising soil PH and it seems I should have added lime last autumn!

I can get my hands on hydrated lime easily, but wary of adding to my grow

 

[Justinsane]

It's a definite way of determining if you're anywhere near where you need to be... and you re NOT currently...

https://www.autoflower.org/f42/ph-potential-hydrogen-manual-11586.html

correct to 6.3 - 6.5 and then proceed as normal...

in 6.5 out 5.3 suggests soil ph around 4.9 ish.... this is a dire corrective emergency!

see charts in above link!

So if my ph in is 7.3 then my run off should be 6.8 ish to be good, right? So i should raise it almost 1.0. How much dolomite lime is that for 12 liter soil?

Justin

 

[JM]

couldnt tell ya exactly on the lime... but I will say its still fairly sow acting... and ideally in a soil based medium, you want 6.3 - 6.5 as indicated in the charts...

I'd reccomend flushing 2 times the pot's volume with ph up or down solution like for hydro... vinegar works ok for down... and baking soda for up... but I'd reccomend starting with VERY small amounts and waiting at LEAST 1 hour after adding and thoroughly stirring before trusting a ph read of it.

flush first time with something like 7.0 (plain water ph buffered) the volume of the pot...

then....


after that hold 6.5 in your flush solution and flush 2 times more the volume of the pot.

then see if your runoff has returned to the 6.3- 6.5 range

ideally, 6.5 in and 6.5 out,

notice on the first chart that thats where all the nutrients meet on the chart?

 

[Justinsane]

couldnt tell ya exactly on the lime... but I will say its still fairly sow acting... and ideally in a soil based medium, you want 6.3 - 6.5 as indicated in the charts...

I'd reccomend flushing 2 times the pot's volume with ph up or down solution like for hydro... vinegar works ok for down... and baking soda for up... but I'd reccomend starting with VERY small amounts and waiting at LEAST 1 hour after adding and thoroughly stirring before trusting a ph read of it.

flush first time with something like 7.0 (plain water ph buffered) the volume of the pot...

then....


after that hold 6.5 in your flush solution and flush 2 times more the volume of the pot.

then see if your runoff has returned to the 6.3- 6.5 range

ideally, 6.5 in and 6.5 out,

notice on the first chart that thats where all the nutrients meet on the chart?

Sir yes sir!

Im on it right now, be back with result in a few hours.

Many thanks friend.

Love justin