Take care when applying SO4

I decided last week that our garden was needing some calcium.  The soil structure had declined considerably since earlier this spring, and it was becoming difficult to till (hoe).  I was also wanting to increase the quality of the potatoes and reduce the onset of blossom end rot in tomatoes(http://blog.calciumproducts.com/posts/blossom-end-rot-.cfm)

Thursday evening I applied SO4.  It was very difficult to get between the rows of potatoes, so I top spread the area, and then turned on the water for 2 hours.  Friday morning, my wife harvested some onions, which were near the potatoes, and was surprised that she couldn't stand to eat them.  She also couldn't stand to cut the tops off of more than 2-3 at a time without tears. 

Conclusion: the sulfur level in the onion had increased significantly.  Link:(http://www.coolquiz.com/trivia/explain/docs/onion.asp)

Lesson learned & a very evident (tearful) demonstration of the solubility of SO4.  In this case, less than 12 hours & 0.4" of water were sufficient for the product to break down & be taken up by the plant.  If you have plants that you don't want to more pungent (radishes, peppers), please take care when applying SO4.