gdogfunkanswered grow question 5 years ago Why only calcium? When I started growing indoors a little more than 2 yrs ago, I did a ton of reading. In my experience, I have found that using a quality Cal-mag each and every watering (I'm using a very intense LED), a potassium silicate supplement for sturdy stalks and using a good humate such as URB organic, and then Hi-Brix Molasses for Plants as 'food' for the soil microbes and my plants are as healthy as can be. "Feed the soil, not the plants" is what I live by and I can see my plants thanking me for my research :) I only feed the URB and Sturdy Stalk supplement every other watering and the MFP on feed days.