Can I mix coco noir to organic potting soil to lower pH

Hey all, fist time grower. Using a grow tent with LED light and temperature/humidity sensor to keep ideal conditions. I bought 1 super lemon haze clone and simply started by planting the rock wool into plain miracle grow potting soil (all I had and due to covid-19 hard to get something else quick enough). I bought just the one clone so I could learn and not destroy many plants at once if I screwed up.

Anyway, the plant is growing really well, it’s been in the tent for 16 days now and is about 10 inches tall with good growth. I am using Fox Farm liquid fertilizer (Big Bloom/Grow Big/Tiger Bloom) following the feeding schedule on their site (bottom foxfarm dot com feeding schedules page). I made a water pH of about 6.2-6.5 that I mix the fertilizer. I am still only feeding Big Bloom so far and I used half of the suggested dose (3tsp per gallon instead of suggested 6tsp).

I have a pH/ppm/moisture sensor that you stick in the soil and use the moisture reading to determine when to water. The pH reading is still 7 even though I am using the more acidic water. I assume that won’t change unless I change the soil, and that’s why I’m here. I’ve read about all these complex recipes for soil which I’m sure I’ll get more into as I learn/experience more, but right now that’s too overwhelming and I’m not in a position during the pandemic to be going back and forth to the nursery and lots of stuff online has high delivery times/out of stock.

So the plant is in a small pot still, but plan to transplant it to a 5-gallon grow bag and that finally brings me to my question. Given my fertilizers that I have and the current setup, what is the best soil for transplanting? I am leaning towards buying coco noir pith and mixing with the organic miracle gro potting soil in order to reduce overall pH. I’ve read that coco is low in nitrates which you need to consider if only using coco (soilless), but should I be concerned about this if I mix with potting soil? Can I simply mix 2/3 potting soil and 1/3 coco noir and transplant?


@PlatoGrow I use a mix of 3 parts FF Ocean Forest (1.5 cu ft), 1 part organic compost (.5 cu ft), 1 block of coco with perlite and dolomite lime. I am told that unbuffered coco can attract calcium and therefore not make it readily available to the plant. To hydrate and buffer the coco before mixing with the soil add 7.5 ml of CalMag or CaliMagic to one gallon of water. I don’t know if adding coco promotes or hinders the plants, but that is what I came up with for a mix I use in fabric pots.

Thanks for the tip, I found an article about unbuffered coco coir.

I have no idea where I read it. Probably some product advertisement. Also, I was going to mention the pronged meters are ok for moisture but don’t rely on them for accurate PH readings. It took me a couple of grows and the forum telling me to check PH or what is PH of water and nutrients. You will need a pen to do that.

I’m wondering if I buy something like “Canna Organic Substrate” which is pre-buffered coco and mix that with organic potting mix if that would work. Do I still need to add perlite if that is already in the potting mix?

Thanks for the tip on the pH pen.

how do you lower the ph in coco, my plants are young. and my ph is 7.5 can I use diatomaceous earth or lime thanks for the help ray

I thought lime increases ph and peat lowers ??
When I had a fish that liked a lower ph I would put peat in the filter seemed to work