2 good articles on pH and Potting Mix

PureHarvest · March 21, 2016

From Promix's website.

Explains what limestone does for the mix and how long it takes to react with the first watering for pH adjust (7 days from initial watering).

http://www.pthorticulture.com/en/tra...growing-media/

And this article explains how the pH of your water source is important in relation to it's alkalinity content.
This information leads me to think that if you are going to re-use potting mix you need to seriously consider adding limestone again the second year to adjust what has been changed by the alkalinity (or lack of) of your water and the nitrogen source you used, as it is reacting with the calcium carbonate in your potting mix:

http://www.pthorticulture.com/en/tra...-to-medium-ph/

March 21, 2016	#1
PureHarvest Tomatovillian™ Join Date: Mar 2014 Location: Mid-Atlantic right on the line of Zone 7a and 7b Posts: 1,369	2 good articles on pH and Potting Mix From Promix's website. Explains what limestone does for the mix and how long it takes to react with the first watering for pH adjust (7 days from initial watering). http://www.pthorticulture.com/en/tra...growing-media/ And this article explains how the pH of your water source is important in relation to it's alkalinity content. This information leads me to think that if you are going to re-use potting mix you need to seriously consider adding limestone again the second year to adjust what has been changed by the alkalinity (or lack of) of your water and the nitrogen source you used, as it is reacting with the calcium carbonate in your potting mix: http://www.pthorticulture.com/en/tra...-to-medium-ph/ Last edited by PureHarvest; March 21, 2016 at 10:14 AM.