Ph dropped from 7 to 4.7 in 3 days!

[Lightning182]

I transplanted my 7inch clones from Dixie cups from the club to fox farm soil, I watered them with purified water, until it came out the holes at the bottom, outa a 5 gallon jug bought new at walmart. The waters ph is a perfect 7, my soil still in the bag is a perfect 7 but after only 3 days the ph in both pots has dropped to 4.7! Any ideas?? Anything would help.

My light is a 150watt placed 20in above the tallest plant. My room is good temp at 77f with 40% humidity.

 

[LEDman]

How do you measure your soil pH? Maybe your pH meter needs to be recalibrated...

 

[Lightning182]

A digital one from home depot for 15 bucks. A few of my friends use the same one. I don't think it can be calibrated.

 

[LEDman]

So what's your runoff pH, then? Maybe your pH meter is not equipped for measuring soil pH...

 

[Lightning182]

It says on the box for soil and my buddies use the same one. Anyways it's all good now, time came to water again, the next day after watering everything was good, both pots measured 6.3to6.5. Do u measure water run off with the strips?

 

[quietonthe401]

Dig them back up and add a few handfulls of dolomitic lime to the soil and mix alot,make sure its powder. Your ph problems go out the door.

 

[Lightning182]

Iv read that a lot maybe next time, the ph level are cool now.

 

[Bud Beans]

some time temperature make drop ph