Best way to up soil pH quickly?

Hi guys. I have finally got a soil pH kit and done runoff and soil probe tests and noticed the medium is a bit acidic. I have not the ability to test ppm of runoff sadly.

I'm using scotts premium seeding mix (no other reason than having it on hand) with 20% perlite (mix of coir, peat and bark compost from what I can see). I have one small GG#4 auto at 4wks in a 5 gal pot under terrible lighting (23w) which isn't a concern, and one gg#4 auto going on seven weeks (3rd of flower).

Lights off after weekly foliar feed (yesterday)


The medium is testing 5.0 with the younger plant and 5.5 for the plant in flower using the probe. The slurry test is at 5.5 for the younger plant and 5.8 for the plant in flower. I'm watering with tap water and a weak dose of Canna Terra Flores (6ml to 2L), boost (3ml to 2L) and Cannazym (4ml to 2L) which comes out around 6.6-6.8pH.

I've read that pH of potting mix/soil should be around 6.0-6.5, so I'd assume low 5's is a bit out of whack, and probably due to using slow release soil alongside feeding when flower kicked in. The only way I've ever raised soil pH was top dressing with dolomite lime. Have any of you guys got a more effective method of raising soil pH quickly? Or am I just stressing over nothing at this point?

Cheers.

potassium carbonate will do the job quickly

go go kid said:

potassium carbonate will do the job quickly

Click to expand...

just remember a little goes along way

you can get it from soap makers sites

Cheers.

Ive got a craft shop down the road that sells 99.5 potassium carbonate in 250g tubs for a few bucks so I'll do a bit if research give that a whirl.