I observed something strange in one of my newly built and spring planted wildflower boxes this year. An area of 2 feet x 2 feet was completely bare even though I kept reseeding and reseeding and reseeding till I finally gave up. Nothing would grow there even the most noxious invasive weeds which I saw start to sprout and then kind of whither away. It was very strange. I initially suspected that a couple of bags of dirt I bought from Menards was contaminated with a chemical like Round Up.
When cleaning the garage the other day I noticed a stain on the floor that had been caused by me leaving this Citrus cleaner in a coffee can. The cleaner is that orange liquid stuff that you can get at Home Depot and smells like oranges but the instructions demand that you wear gloves when using it so it must be pretty corrosive. It was corrosive enough to eat through the bottom of the coffee can, get onto the cement floor, and eat into the cement. I kind of forgot about the coffee can for a month last year until I discovered the mess so the chemicals had a long time to change their molecules. Anyway, right next to this little chemical spill were two extra bags of potting soil that I had stored and I think perhaps made contact with this chemical and might have absorbed a lot of it. When tracing back what happened, I think I remember grabbing those two bags to get rid of them not giving a second thought about the contamination. At that time, in the early spring when I installed these boxes, I was hauling a lot of soil. Each wildflower box takes 25 bags of dirt/compost/peat/whatever.
So this blighted area in the box most likely was my fault. My question to anyone who knows: Will this chemical eventually wash out of the box on its own? My boxes have very good drainage systems. In the fall I need to make a decision whether to extract all the dirt in that area and replace it or just hope the fall and winter precipitation will clean out the dirt. This box is located on my main rooftop making getting dirt up there a lot of effort but I'll do it if necessary.
Here's a pic of the box in question: