pLEASE HELP! Need PH advice ASAP!

Ok this is my first grow, I'm using FFOF soil in 7gal pots. I've been noticing slow growth and decided to check my PH Runoff for the first time. The plant is 3 weeks old, and the runoff read at 4.0! The water i put in was 7.0 ...I'm not sure how to correct this & need prof advise plz. Thnx

ffof is pretty hot. especially some batches over others. I would carefully add in some lime or water with molasses as it can help buffer soil

thx for help, how much lime for a 7 gal pot? & i've been using molasses for the last 2 waterings, 2 tbl per gal

1 tsp per soil gallon but that's premixing with the soil. You might try 2 tsp to the top soil at watering til you achieve 7 tsp..