Disclaimer: This post was originally posted by Full Member, Eric-02476. This user is located in Zone 6A Eastern MA. This was originally posted on May 19, 2014.
I've learned the hard way that blindly adding "2 cups of dolomite" isn't such a great idea. 2 cups can add up to much more than the recommended 1 pound. Read on:
To save major money, I buy 40-pound bags of pulverized dolomitic limestone for about $5 from my local hardware store, in the lawn section (gasp). The label analysis shows calcium and magnesium in the desired concentrations and proportions. All good for Earthboxes, right? Yes, and so much cheaper than buying small bags of dolomite from the horticultural section.
But I forgot one thing: density.
See, as an avid Earthbox user for 10 years or more, I've long been in the habit of following the "classic" instructions to add 2 cups of dolomite when replanting. This year, when reviewing the latest replanting instructions online, I see the company now says to add one pound. So I got out my kitchen scale, sheathed it in a ziploc bag, and weighed 2 cups of my dolomite. It came to almost 2 pounds!
So, I've been WAY over-liming my EBs for who knows how long. Perhaps not coincidentally, I've had more trouble than usual in recent years with inexplicable signs of nutrient deficiencies in various plants. I wonder if I've been making the potting media too alkaline over the years. That can certainly affect nutrient uptake.
Bottom line: know how much YOUR dolomite weighs, especially if you're going rogue like me and buying it in those 40 pound bags in the "wrong" section of the garden center!
Eric
